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Meng Y, Li CX, Zhang X. Quantitative Evaluation of Oxygen Extraction Fraction Changes in the Monkey Brain during Acute Stroke by Using Quantitative Susceptibility Mapping. Life (Basel) 2023; 13:1008. [PMID: 37109537 PMCID: PMC10146121 DOI: 10.3390/life13041008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND The oxygen extraction fraction (OEF) indicates the brain's oxygen consumption and can be estimated by using the quantitative susceptibility mapping (QSM) MRI technique. Recent studies have suggested that OEF alteration following stroke is associated with the viability of at-risk tissue. In the present study, the temporal evolution of OEF in the monkey brain during acute stroke was investigated using QSM. METHODS Ischemic stroke was induced in adult rhesus monkeys (n = 8) with permanent middle cerebral artery occlusion (pMCAO) by using an interventional approach. Diffusion-, T2-, and T2*-weighted images were conducted on day 0, day 2, and day 4 post-stroke using a clinical 3T scanner. Progressive changes in magnetic susceptibility and OEF, along with their correlations with the transverse relaxation rates and diffusion indices, were examined. RESULTS The magnetic susceptibility and OEF in injured gray matter of the brain significantly increased during the hyperacute phase, and then decreased significantly on day 2 and day 4. Moreover, the temporal changes of OEF in gray matter were moderately correlated with mean diffusivity (MD) (r = 0.52; p = 0.046) from day 0 to day 4. Magnetic susceptibility in white matter progressively increased (from negative values to near zero) during acute stroke, and significant increases were seen on day 2 (p = 0.08) and day 4 (p = 0.003) when white matter was significantly degenerated. However, significant reduction of OEF in white matter was not seen until day 4 post-stroke. CONCLUSION The preliminary results demonstrate that QSM-derived OEF is a robust approach to examine the progressive changes of gray matter in the ischemic brain from the hyperacute phase to the subacute phase of stroke. The changes of OEF in gray matter were more prominent than those in white matter following stroke insult. The findings suggest that QSM-derived OEF may provide complementary information for understanding the neuropathology of the brain tissue following stroke and predicting stroke outcomes.
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Affiliation(s)
- Yuguang Meng
- EPC Imaging Center, Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
| | - Chun-Xia Li
- EPC Imaging Center, Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
| | - Xiaodong Zhang
- EPC Imaging Center, Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, Atlanta, GA 30329, USA
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Nagy SA, Ivic I, Tóth P, Komoly S, Kiss T, Pénzes M, Málnási-Csizmadia A, Dóczi T, Perlaki G, Orsi G. Post-reperfusion acute MR diffusion in stroke is a potential predictor for clinical outcome in rats. Sci Rep 2023; 13:5598. [PMID: 37019923 PMCID: PMC10076321 DOI: 10.1038/s41598-023-32679-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
Middle cerebral artery occlusion (MCAO) models show substantial variability in outcome, introducing uncertainties in the evaluation of treatment effects. Early outcome predictors would be essential for prognostic purposes and variability control. We aimed to compare apparent diffusion coefficient (ADC) MRI data obtained during MCAO and shortly after reperfusion for their potentials in acute-phase outcome prediction. Fifty-nine male rats underwent a 45-min MCAO. Outcome was defined in three ways: 21-day survival; 24 h midline-shift and neurological scores. Animals were divided into two groups: rats surviving 21 days after MCAO (survival group, n = 46) and rats dying prematurely (non-survival/NS group, n = 13). At reperfusion, NS group showed considerably larger lesion volume and lower mean ADC of the initial lesion site (p < 0.0001), while during occlusion there were no significant group differences. At reperfusion, each survival animal showed decreased lesion volume and increased mean ADC of the initial lesion site compared to those during occlusion (p < 10-6), while NS group showed a mixed pattern. At reperfusion, lesion volume and mean ADC of the initial lesion site were significantly associated with 24 h midline-shift and neurological scores. Diffusion MRI performed soon after reperfusion has a great impact in early-phase outcome prediction, and it works better than the measurement during occlusion.
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Affiliation(s)
- Szilvia Anett Nagy
- ELKH-PTE Clinical Neuroscience MR Research Group, Ret Str. 2, 7623, Pecs, Hungary.
- Pecs Diagnostic Centre, Rét Street 2, 7623, Pecs, Hungary.
- Structural Neurobiology Research Group, Szentágothai Research Centre, University of Pecs, Ifjúság Street 20, 7624, Pecs, Hungary.
- Department of Neurology, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary.
| | - Ivan Ivic
- Pecs Diagnostic Centre, Rét Street 2, 7623, Pecs, Hungary
- Selvita d.o.o., Prilaz Baruna Filipovića 29, 10000, Zagreb, Croatia
| | - Péter Tóth
- ELKH-PTE Clinical Neuroscience MR Research Group, Ret Str. 2, 7623, Pecs, Hungary
- Department of Neurosurgery, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
| | - Sámuel Komoly
- Department of Neurology, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
| | - Tamás Kiss
- Szentágothai Research Centre, University of Pecs, Ifjúság Street 20, Pecs, Hungary
| | - Máté Pénzes
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter Sétány 1/C, 1117, Budapest, Hungary
- Motorpharma Ltd., Szilágyi E. Fasor 27, 1026, Budapest, Hungary
| | - András Málnási-Csizmadia
- Motorpharma Ltd., Szilágyi E. Fasor 27, 1026, Budapest, Hungary
- ELKH-ELTE Motor Pharmacology Research Group, Department of Biochemistry, Eötvös Loránd University, Pázmány Péter Sétány 1/C, 1117, Budapest, Hungary
| | - Tamás Dóczi
- Pecs Diagnostic Centre, Rét Street 2, 7623, Pecs, Hungary
- Department of Neurosurgery, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
| | - Gábor Perlaki
- ELKH-PTE Clinical Neuroscience MR Research Group, Ret Str. 2, 7623, Pecs, Hungary
- Pecs Diagnostic Centre, Rét Street 2, 7623, Pecs, Hungary
- Department of Neurology, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
- Department of Neurosurgery, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
| | - Gergely Orsi
- ELKH-PTE Clinical Neuroscience MR Research Group, Ret Str. 2, 7623, Pecs, Hungary
- Pecs Diagnostic Centre, Rét Street 2, 7623, Pecs, Hungary
- Department of Neurology, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
- Department of Neurosurgery, Medical School, University of Pecs, Rét Street 2, 7623, Pecs, Hungary
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Conti E, Piccardi B, Sodero A, Tudisco L, Lombardo I, Fainardi E, Nencini P, Sarti C, Allegra Mascaro AL, Baldereschi M. Translational Stroke Research Review: Using the Mouse to Model Human Futile Recanalization and Reperfusion Injury in Ischemic Brain Tissue. Cells 2021; 10:3308. [PMID: 34943816 PMCID: PMC8699609 DOI: 10.3390/cells10123308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 12/20/2022] Open
Abstract
The approach to reperfusion therapies in stroke patients is rapidly evolving, but there is still no explanation why a substantial proportion of patients have a poor clinical prognosis despite successful flow restoration. This issue of futile recanalization is explained here by three clinical cases, which, despite complete recanalization, have very different outcomes. Preclinical research is particularly suited to characterize the highly dynamic changes in acute ischemic stroke and identify potential treatment targets useful for clinical translation. This review surveys the efforts taken so far to achieve mouse models capable of investigating the neurovascular underpinnings of futile recanalization. We highlight the translational potential of targeting tissue reperfusion in fully recanalized mouse models and of investigating the underlying pathophysiological mechanisms from subcellular to tissue scale. We suggest that stroke preclinical research should increasingly drive forward a continuous and circular dialogue with clinical research. When the preclinical and the clinical stroke research are consistent, translational success will follow.
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Affiliation(s)
- Emilia Conti
- Neuroscience Institute, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; (E.C.); (A.L.A.M.)
- European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Benedetta Piccardi
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Alessandro Sodero
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Laura Tudisco
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Ivano Lombardo
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy; (I.L.); (E.F.)
| | - Enrico Fainardi
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy; (I.L.); (E.F.)
| | - Patrizia Nencini
- Stroke Unit, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy;
| | - Cristina Sarti
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Anna Letizia Allegra Mascaro
- Neuroscience Institute, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; (E.C.); (A.L.A.M.)
- European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Marzia Baldereschi
- Neuroscience Institute, National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy;
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Ospel JM, Menon BK, Qiu W, Kashani N, Mayank A, Singh N, Cimflova P, Marko M, Nogueira RG, McTaggart RA, Demchuk AM, Poppe AY, Zerna C, Joshi M, Almekhlafi MA, Haussen D, Cutting S, Coutts SB, Roy D, Rohr A, Iancu D, Tymianski M, Hill MD, Goyal M. A Detailed Analysis of Infarct Patterns and Volumes at 24-hour Noncontrast CT and Diffusion-weighted MRI in Acute Ischemic Stroke Due to Large Vessel Occlusion: Results from the ESCAPE-NA1 Trial. Radiology 2021; 300:152-159. [PMID: 33973838 DOI: 10.1148/radiol.2021203964] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Background The effect of infarct pattern on functional outcome in acute ischemic stroke is incompletely understood. Purpose To investigate the association of qualitative and quantitative infarct variables at 24-hour follow-up noncontrast CT and diffusion-weighted MRI with 90-day clinical outcome. Materials and Methods The Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke, or ESCAPE-NA1, randomized controlled trial enrolled patients with large-vessel-occlusion stroke undergoing mechanical thrombectomy from March 1, 2017, to August 12, 2019. In this post hoc analysis of the trial, qualitative infarct variables (predominantly gray [vs gray and white] matter involvement, corticospinal tract involvement, infarct structure [scattered vs territorial]) and total infarct volume were assessed at 24-hour follow-up noncontrast CT or diffusion-weighted MRI. White and gray matter infarct volumes were assessed in patients by using follow-up diffusion-weighted MRI. Infarct variables were compared between patients with and those without good outcome, defined as a modified Rankin Scale score of 0-2 at 90 days. The association of infarct variables with good outcome was determined with use of multivariable logistic regression. Separate regression models were used to report effect size estimates with adjustment for total infarct volume. Results Qualitative infarct variables were assessed in 1026 patients (mean age ± standard deviation, 69 years ± 13; 522 men) and quantitative infarct variables were assessed in a subgroup of 358 of 1026 patients (mean age, 67 years ± 13; 190 women). Patients with gray and white matter involvement (odds ratio [OR] after multivariable adjustment, 0.19; 95% CI: 0.14, 0.25; P < .001), corticospinal tract involvement (OR after multivariable adjustment, 0.06; 95% CI: 0.04, 0.10; P < .001), and territorial infarcts (OR after multivariable adjustment, 0.22; 95% CI: 0.14, 0.32; P < .001) were less likely to achieve good outcome, independent of total infarct volume. Conclusion Infarct confinement to the gray matter, corticospinal tract sparing, and scattered infarct structure at 24-hour noncontrast CT and diffusion-weighted MRI were highly predictive of good 90-day clinical outcome, independent of total infarct volume. Clinical trial registration no. NCT02930018 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Mossa-Basha in this issue.
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Affiliation(s)
- Johanna M Ospel
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Bijoy K Menon
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Wu Qiu
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Nima Kashani
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Arnuv Mayank
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Nishita Singh
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Petra Cimflova
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Martha Marko
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Raul G Nogueira
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Ryan A McTaggart
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Andrew M Demchuk
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Alexandre Y Poppe
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Charlotte Zerna
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Manish Joshi
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Mohammed A Almekhlafi
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Diogo Haussen
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Shawna Cutting
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Shelagh B Coutts
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Daniel Roy
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Axel Rohr
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Dana Iancu
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Michael Tymianski
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Michael D Hill
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | - Mayank Goyal
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
| | -
- From the Department of Clinical Neurosciences and Diagnostic Imaging, University of Calgary Cumming School of Medicine, 29th St NW, 1079 A, Calgary, AB, Canada T2N 2T9 (J.M.O., B.K.M., W.Q., N.K., A.M., N.S., P.C., M.M., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Radiology, University Hospital of Basel, Basel, Switzerland (J.M.O.); Department of Radiology, University of Calgary, Calgary, Alberta, Canada (B.K.M., N.K., A.M.D., C.Z., M.J., M.A.A., S.B.C., M.D.H., M.G.); Department of Medical Imaging, St Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic (P.C.); International Clinical Research Center, St Anne's University Hospital Brno, Czech Republic (P.C.); Department of Neurology, Emory University School of Medicine, Atlanta, Ga (R.G.N., D.H.); Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (R.A.M.); Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada (A.Y.P., D.R., D.I.); Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI (S.C.); Department of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada (A.R.); and NoNo, Toronto, Ontario, Canada (M.T.)
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5
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Shi ZF, Fang Q, Chen Y, Xu LX, Wu M, Jia M, Lu Y, Wang XX, Wang YJ, Yan X, Dong LP, Yuan F. Methylene blue ameliorates brain edema in rats with experimental ischemic stroke via inhibiting aquaporin 4 expression. Acta Pharmacol Sin 2021; 42:382-392. [PMID: 32665706 PMCID: PMC8027449 DOI: 10.1038/s41401-020-0468-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/23/2020] [Indexed: 12/23/2022] Open
Abstract
Brain edema is a common and serious complication of ischemic stroke with limited effective treatment. We previously reported that methylene blue (MB) attenuated ischemic brain edema in rats, but the underlying mechanisms remained unknown. Aquaporin 4 (AQP4) in astrocytes plays a key role in brain edema. We also found that extracellular signal-regulated kinase 1/2 (ERK1/2) activation was involved in the regulation of AQP4 expression in astrocytes. In the present study, we investigated whether AQP4 and ERK1/2 were involved in the protective effect of MB against cerebral edema. Rats were subjected to transient middle cerebral artery occlusion (tMCAO), MB (3 mg/kg, for 30 min) was infused intravenously through the tail vein started immediately after reperfusion and again at 3 h after ischemia (1.5 mg/kg, for 15 min). Brain edema was determined by MRI at 0.5, 2.5, and 48 h after tMCAO. The decreases of apparent diffusion coefficient (ADC) values on diffusion-weighted MRI indicated cytotoxic brain edema, whereas the increase of T2 MRI values reflected vasogenic brain edema. We found that MB infusion significantly ameliorated cytotoxic brain edema at 2.5 and 48 h after tMCAO and decreased vasogenic brain edema at 48 h after tMCAO. In addition, MB infusion blocked the AQP4 increases and ERK1/2 activation in the cerebral cortex in ischemic penumbra at 48 h after tMCAO. In a cell swelling model established in cultured rat astrocyte exposed to glutamate (1 mM), we consistently found that MB (10 μM) attenuated cell swelling, AQP4 increases and ERK1/2 activation. Moreover, the ERK1/2 inhibitor U0126 (10 μM) had the similar effects as MB. These results demonstrate that MB improves brain edema and astrocyte swelling, which may be mediated by the inhibition of AQP4 expression via ERK1/2 pathway, suggesting that MB may be a potential choice for the treatment of brain edema.
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Affiliation(s)
- Zhong-Fang Shi
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
- Beijing Key Laboratory of Central Nervous System Injury, Beijing, 100070, China
| | - Qing Fang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Ye Chen
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Li-Xin Xu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Min Wu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Mei Jia
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Yi Lu
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Xiao-Xuan Wang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Yu-Jiao Wang
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Xu Yan
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Li-Ping Dong
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Fang Yuan
- Department of Pathophysiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.
- Beijing Key Laboratory of Central Nervous System Injury, Beijing, 100070, China.
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6
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Li Y, Li R, Liu M, Nie Z, Muir ER, Duong TQ. MRI study of cerebral blood flow, vascular reactivity, and vascular coupling in systemic hypertension. Brain Res 2020; 1753:147224. [PMID: 33358732 DOI: 10.1016/j.brainres.2020.147224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/30/2020] [Accepted: 11/27/2020] [Indexed: 01/14/2023]
Abstract
Chronic hypertension alters cerebrovascular function, which can lead to neurovascular pathologies and increased susceptibility to neurological disorders. The purpose of this study was to utilize in vivo MRI methods with corroborating immunohistology to evaluate neurovascular dysfunction due to progressive chronic hypertension. The spontaneously hypertensive rat (SHR) model at different stages of hypertension was studied to evaluate: i) basal cerebral blood flow (CBF), ii) cerebrovascular reactivity (CVR) assessed by CBF and blood-oxygenation level dependent (BOLD) signal changes to hypercapnia, iii) neurovascular coupling from CBF and BOLD changes to forepaw stimulation, and iv) damage of neurovascular unit (NVU) components (microvascular, astrocyte and neuron densities). Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR (mild hypertension), basal CBF was higher (p < 0.05), CVR trended higher, and neurovascular coupling response was higher (p < 0.05), compared to normotensive rats. In 40-week SHR (severe hypertension), basal CBF, CVR, and neurovascular coupling response were reversed to similar or below normotensive rats, and were significantly different from 10-week SHR (p < 0.05). Immunohistological analysis found significantly reduced microvascular density, increased astrocytes, and reduced neuronal density in SHR at 40 weeks (p < 0.05) but not at 10 weeks (p > 0.05) in comparison to age-matched controls. In conclusion, we observed a bi-phasic basal CBF, CVR and neurovascular coupling response from early to late hypertension using in vivo MRI, with significant changes prior to changes in the NVU components from histology. MRI provides clinically relevant data that might be useful to characterize neurovascular pathogenesis on the brain in hypertension.
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Affiliation(s)
- Yunxia Li
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Renren Li
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Meng Liu
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhiyu Nie
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Eric R Muir
- Department of Radiology, Renaissance School of Medicine, Stony Brook University Hospital, Stony Brook, NY, USA
| | - Tim Q Duong
- Department of Radiology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, USA.
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7
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Huang HT, Tung TH, Lin M, Wang X, Li X, Liang K, Qian Q, Chen PE. Characterizing spatiotemporal progression and prediction of infarct lesion volumes in experimental acute ischemia using quantitative perfusion and diffusion imaging. Appl Radiat Isot 2020; 168:109522. [PMID: 33290998 DOI: 10.1016/j.apradiso.2020.109522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 11/09/2020] [Accepted: 11/15/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE This study was conducted to explore the diagnostic value of arterial spin labeling (ASL) combined with diffusion weighted imaging (DWI) in characterizing the spatiotemporal progression of infarct lesions in a rabbit middle cerebral artery occlusion (MCAO) model and predicting the acute cerebral infarction (ACI) volume. MATERIALS AND METHODS Forty-two male rabbits (2.9 ± 0.2 kg body weight) were used in this experimental study. Animals were initially anesthetized by intravenous injection of uratan. There were seven experimental groups with six rabbits in each group. The apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) thresholds were established in the control group (n = 6), which were sacrificed at 12 h, stained for infarct volume, and imaged at each time point. RESULTS The normal ADC and CBF were estimated as 0.90 ± 0.03 × 10-3 mm2/s and 0.68 ± 0.06 mL g-1 min-1, respectively. The viability thresholds of ADC and CBF yielding the lesion volumes (LVs) at 3 h, which best approximated the 2,3,5-triphenyltetrazolium chloride (TTC) infarct volumes at 12 h, were 0.52 ± 0.02 × 10-3 mm2/s (42.2 ± 3% reduction) and 0.33 ± 0.09 mL g-1 min-1 (51.0 ± 11% reduction), respectively. The temporal evolution of the ADC- and CBF-defined LVs showed a significant perfusion/diffusion mismatch up to 1 h (p = 0.001). CONCLUSION ADC values and ACI volumes were positively correlated, while CBF was negatively correlated, which is supposed to be a reference for predicting ACI volume.
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Affiliation(s)
- Hai-Tao Huang
- Department of MRI, Maoming People's Hospital, Guangdong Province, China.
| | - Tao-Hsin Tung
- Department of Medical Research and Education, Cheng Hsin General Hospital, Taipei, Taiwan, China.
| | - Min Lin
- Department of Radiology, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Zhejiang Province, China.
| | - Xinmin Wang
- Department of MRI, Maoming People's Hospital, Guangdong Province, China.
| | - Xie Li
- Department of Computed Tomography, Maoming People's Hospital, Guangdong Province, China.
| | - Kaimin Liang
- Department of MRI, Maoming People's Hospital, Guangdong Province, China.
| | - Qi Qian
- Department of Radiology, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Zhejiang Province, China.
| | - Pei-En Chen
- Institute of Health Policy and Management, National Taiwan University, Taipei, Taiwan, China; Taiwan association of health industry management and development, Taipei, Taiwan, China.
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8
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Biju KC, Shen Q, Hernandez ET, Mader MJ, Clark RA. Reduced cerebral blood flow in an α-synuclein transgenic mouse model of Parkinson's disease. J Cereb Blood Flow Metab 2020; 40:2441-2453. [PMID: 31856640 PMCID: PMC7820695 DOI: 10.1177/0271678x19895432] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
There is increasing evidence that widespread cortical cerebral blood flow deficits occur early in the course of Parkinson's disease. Although cerebral blood flow measurement has been suggested as a potential biomarker for early diagnosis of Parkinson's disease, as well as a means for tracking response to treatment, the relationship of cerebral blood flow to α-synucleinopathy, a major pathological hallmark of Parkinson's disease, remains unclear. Therefore, we performed arterial spin-labeling magnetic resonance imaging and diffusion tensor imaging on transgenic mice overexpressing human wild-type α-synuclein and age-matched controls to measure cerebral blood flow and degenerative changes. As reported for early-stage Parkinson's disease, α-synuclein mice exhibited a significant reduction in cortical cerebral blood flow, which was accompanied by motor coordination deficits and olfactory dysfunction. Although no overt degenerative changes were apparent in diffusion tensor imaging images, magnetic resonance imaging volumetric analysis revealed a significant reduction in olfactory bulb volume, similar to that seen in Parkinson's disease patients. Our data, representing the first report of cerebral blood flow deficit in an animal model of Parkinson's disease, suggest a causative role for α-synucleinopathy in cerebral blood flow deficits in Parkinson's disease. Thus, α-synuclein transgenic mice comprise a promising model to study Parkinson's disease-related mechanisms of cerebral blood flow deficits and to investigate further its utility as a potential biomarker for Parkinson's disease.
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Affiliation(s)
- K C Biju
- Department of Medicine, UT Health San Antonio, San Antonio, TX, USA
| | - Qiang Shen
- Research Imaging Institute, UT Health San Antonio, San Antonio, TX, USA.,Department of Radiology, UT Health San Antonio, San Antonio, TX, USA
| | | | - Michael J Mader
- South Texas Veterans Health Care System, San Antonio, TX, USA
| | - Robert A Clark
- Department of Medicine, UT Health San Antonio, San Antonio, TX, USA.,South Texas Veterans Health Care System, San Antonio, TX, USA
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9
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Goyal M, Ospel JM, Menon B, Almekhlafi M, Jayaraman M, Fiehler J, Psychogios M, Chapot R, van der Lugt A, Liu J, Yang P, Agid R, Hacke W, Walker M, Fischer U, Asdaghi N, McTaggart R, Srivastava P, Nogueira RG, Moret J, Saver JL, Hill MD, Dippel D, Fisher M. Challenging the Ischemic Core Concept in Acute Ischemic Stroke Imaging. Stroke 2020; 51:3147-3155. [DOI: 10.1161/strokeaha.120.030620] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endovascular treatment is a highly effective therapy for acute ischemic stroke due to large vessel occlusion and has recently revolutionized stroke care. Oftentimes, ischemic core extent on baseline imaging is used to determine endovascular treatment-eligibility. There are, however, 3 fundamental issues with the core concept: First, computed tomography and magnetic resonance imaging, which are mostly used in the acute stroke setting, are not able to precisely determine whether and to what extent brain tissue is infarcted (core) or still viable, due to variability in tissue vulnerability, the phenomenon of selective neuronal loss and lack of a reliable gold standard. Second, treatment decision-making in acute stroke is multifactorial, and as such, the relative importance of single variables, including imaging factors, is reduced. Third, there are often discrepancies between core volume and clinical outcome. This review will address the uncertainty in terminology and proposes a direction towards more clarity. This theoretical exercise needs empirical data that clarify the definitions further and prove its value.
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Affiliation(s)
- Mayank Goyal
- Department of Clinical Neurosciences, University of Calgary, Canada. (M.G., J.M.O., B.M., M.A., M.D.H.)
- Department of Radiology, University of Calgary, Canada. (M.G., B.M., M.A., M.D.H.)
| | - Johanna M. Ospel
- Department of Clinical Neurosciences, University of Calgary, Canada. (M.G., J.M.O., B.M., M.A., M.D.H.)
- Division of Neuroradiology, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, University of Basel, Switzerland (J.M.O., M.P.)
| | - Bijoy Menon
- Department of Clinical Neurosciences, University of Calgary, Canada. (M.G., J.M.O., B.M., M.A., M.D.H.)
- Department of Radiology, University of Calgary, Canada. (M.G., B.M., M.A., M.D.H.)
| | - Mohammed Almekhlafi
- Department of Clinical Neurosciences, University of Calgary, Canada. (M.G., J.M.O., B.M., M.A., M.D.H.)
- Department of Radiology, University of Calgary, Canada. (M.G., B.M., M.A., M.D.H.)
| | - Mahesh Jayaraman
- Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (M.J., R.M.)
| | - Jens Fiehler
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Germany (J.F.)
| | - Marios Psychogios
- Division of Neuroradiology, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, University of Basel, Switzerland (J.M.O., M.P.)
| | - Rene Chapot
- Department of Neuroradiology, Alfred Krupp Krankenhaus, Essen, Germany (R.C.)
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands (A.v.d.L.)
| | - Jianmin Liu
- Department of Neurosurgery, Changhai Hospital, Naval Medical University, Shanghai, China (J.L.)
| | - Pengfei Yang
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (P.Y.)
| | - Ronit Agid
- Department of Medical Imaging, University of Toronto, Canada (R.A.)
| | - Werner Hacke
- Department of Neurology, University Hospital Heidelberg, Germany (W.H.)
| | - Melanie Walker
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle (M.W.)
| | - Urs Fischer
- Department of Neuroradiology, University Hospital Bern, Inselspital, University of Bern, Switzerland (U.F.)
| | - Negar Asdaghi
- Department of Neurology, University of Miami Miller School of Medicine (N.A.)
| | - Ryan McTaggart
- Department of Interventional Radiology, Warren Alpert Medical School of Brown University, Providence, RI (M.J., R.M.)
| | - Padma Srivastava
- Department of Neurology, All India Institute of Medicine, New Delhi, India (P.S.)
| | - Raul G. Nogueira
- Department of Neurology, Emory University School of Medicine, Atlanta (R.G.N.)
| | - Jacques Moret
- The Brain Vascular Center, Baujon University Hospital, Paris, France (J.M.)
| | - Jeffrey L. Saver
- Department of Neurology and Comprehensive Stroke Center, David Geffen School of Medicine, University of California, Los Angeles (J.L.S.)
| | - Michael D. Hill
- Department of Clinical Neurosciences, University of Calgary, Canada. (M.G., J.M.O., B.M., M.A., M.D.H.)
- Department of Radiology, University of Calgary, Canada. (M.G., B.M., M.A., M.D.H.)
| | - Diederik Dippel
- Department of Neurology, Erasmus University Medical Center, Rotterdam, the Netherlands (D.D.)
| | - Marc Fisher
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA (M.F.)
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10
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Effect of Methylene Blue and PI3K-Akt Pathway Inhibitors on the Neurovascular System after Chronic Cerebral Hypoperfusion in Rats. J Mol Neurosci 2020; 70:1797-1807. [PMID: 32507927 DOI: 10.1007/s12031-020-01572-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/23/2020] [Indexed: 10/24/2022]
Abstract
Methylene blue (MB) has a protective effect on cognitive decline caused by chronic hypoperfusion, but the specific mechanism is not clear. This article aims to determine whether MB protects vascular neurons through PI3K/Akt and plays a role in improving cognitive impairment. Molecular biological methods, the hippocampal neuronal density test, the hippocampal vascular network density test, and dynamic enhanced magnetic resonance imaging (MRI) were used to detect the blood-brain barrier permeability and Evans blue leakage rate in the hippocampus. We also observed and evaluated the changes in the above results after administration of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway protein inhibitor LY294002. There were significant differences for cerebral blood flow (CBF) between the chronic cerebral hypoperfusion (CCH) + MB group (100 ml/100 g/min) and the CCH group (60 ml/100 g/min, P < 0.05). After using LY294002, the CBF of the CCH + MB + LY294002 group dropped to 82 ml/100 g/min. The vascular density in the CCH + MB group was 23%, which is significantly higher than that in the CCH group (15.1%) (P < 0.05). The vascular density (17.5%) in the CCH + MB + LY294002 group was significantly higher than that in the CCH group but lower than that in the CCH + MB group. Western blotting results showed that one week after intraperitoneal injection of MB, the expression of t-Akt and p-Akt in the CCH + MB group was increased after CCH, and LY294002 partially blocked this up-regulation effect (CCH + MB + LY294002 group). MB is a potential therapy for the relief of mild cognitive impairment associated with CCH, vascular dementia, and Alzheimer's disease.
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11
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Biose IJ, Dewar D, Macrae IM, McCabe C. Impact of stroke co-morbidities on cortical collateral flow following ischaemic stroke. J Cereb Blood Flow Metab 2020; 40:978-990. [PMID: 31234703 PMCID: PMC7181095 DOI: 10.1177/0271678x19858532] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Acute hyperglycaemia and chronic hypertension worsen stroke outcome but their impact on collateral perfusion, a determinant of penumbral life span, is poorly understood. Laser-speckle contrast imaging (LSCI) was used to determine the influence of these stroke comorbidities on cortical perfusion after permanent middle cerebral artery occlusion (pMCAO) in spontaneously hypertensive stroke prone rats (SHRSP) and normotensive Wistar rats. Four independent studies were conducted. In animals without pMCAO, cortical perfusion remained stable over 180 min. Following pMCAO, cortical perfusion was markedly reduced at 30 min then gradually increased, via cortical collaterals, over the subsequent 3.5 h. In the contralateral non-ischaemic hemisphere, perfusion did not change over time. Acute hyperglycaemia (in normotensive Wistar) and chronic hypertension (SHRSP) attenuated the restoration of cortical perfusion after pMCAO. Inhaled nitric oxide did not influence cortical perfusion in SHRSP following pMCAO. Thus, hyperglycaemia at the time of arterial occlusion or pre-existing hypertension impaired the dynamic recruitment of cortical collaterals after pMCAO. The impairment of collateral recruitment may contribute to the detrimental effects these comorbidities have on stroke outcome.
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Affiliation(s)
- Ifechukwude J Biose
- Stroke and Brain Imaging, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Department of Anatomy and Forensic Anthropology, Cross River University of Technology, Calabar, Nigeria
| | - Deborah Dewar
- Stroke and Brain Imaging, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Stroke and Brain Imaging, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Christopher McCabe
- Stroke and Brain Imaging, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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12
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Leftin A, Rosenberg JT, Yuan X, Ma T, Grant SC, Frydman L. Multiparametric classification of sub-acute ischemic stroke recovery with ultrafast diffusion, 23 Na, and MPIO-labeled stem cell MRI at 21.1 T. NMR IN BIOMEDICINE 2020; 33:e4186. [PMID: 31797472 PMCID: PMC8170591 DOI: 10.1002/nbm.4186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/11/2019] [Accepted: 07/22/2019] [Indexed: 05/05/2023]
Abstract
MRI leverages multiple modes of contrast to characterize stroke. High-magnetic-field systems enhance the performance of these MRI measurements. Previously, we have demonstrated that individually sodium and stem cell tracking metrics are enhanced at ultrahigh field in a rat model of stroke, and we have developed robust single-scan diffusion-weighted imaging approaches that utilize spatiotemporal encoding (SPEN) of the apparent diffusion coefficient (ADC) for these challenging field strengths. Here, we performed a multiparametric study of middle cerebral artery occlusion (MCAO) biomarker evolution focusing on comparison of these MRI biomarkers for stroke assessment during sub-acute recovery in rat MCAO models at 21.1 T. T2 -weighted MRI was used as the benchmark for identification of the ischemic lesion over the course of the study. The number of MPIO-induced voids measured by gradient-recalled echo, the SPEN measurement of ADC, and 23 Na MRI values were determined in the ischemic area and contralateral hemisphere, and relative performances for stroke classification were compared by receiver operator characteristic analysis. These measurements were associated with unique time-dependent trajectories during stroke recovery that changed the sensitivity and specificity for stroke monitoring during its evolution. Advantages and limitations of these contrasts, and the use of ultrahigh field for multiparametric stroke assessment, are discussed.
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Affiliation(s)
- Avigdor Leftin
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- Department of Radiology, Stony Brook Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Jens T Rosenberg
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Xuegang Yuan
- FAMU-FSU Chemical and Biochemical Engineering, Florida State University, Tallahassee, FL, USA
| | - Teng Ma
- FAMU-FSU Chemical and Biochemical Engineering, Florida State University, Tallahassee, FL, USA
| | - Samuel C Grant
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
- FAMU-FSU Chemical and Biochemical Engineering, Florida State University, Tallahassee, FL, USA
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- FAMU-FSU Chemical and Biochemical Engineering, Florida State University, Tallahassee, FL, USA
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13
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Kaiser EE, West FD. Large animal ischemic stroke models: replicating human stroke pathophysiology. Neural Regen Res 2020; 15:1377-1387. [PMID: 31997796 PMCID: PMC7059570 DOI: 10.4103/1673-5374.274324] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The high morbidity and mortality rate of ischemic stroke in humans has led to the development of numerous animal models that replicate human stroke to further understand the underlying pathophysiology and to explore potential therapeutic interventions. Although promising therapeutics have been identified using these animal models, with most undergoing significant testing in rodent models, the vast majority of these interventions have failed in human clinical trials. This failure of preclinical translation highlights the critical need for better therapeutic assessment in more clinically relevant ischemic stroke animal models. Large animal models such as non-human primates, sheep, pigs, and dogs are likely more predictive of human responses and outcomes due to brain anatomy and physiology that are more similar to humans-potentially making large animal testing a key step in the stroke therapy translational pipeline. The objective of this review is to highlight key characteristics that potentially make these gyrencephalic, large animal ischemic stroke models more predictive by comparing pathophysiological responses, tissue-level changes, and model limitations.
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Affiliation(s)
- Erin E Kaiser
- Regenerative Bioscience Center; Neuroscience Program, Biomedical and Health Sciences Institute; Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Franklin D West
- Regenerative Bioscience Center; Neuroscience Program, Biomedical and Health Sciences Institute; Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
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14
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Moderate Traumatic Brain Injury Alters the Gastrointestinal Microbiome in a Time-Dependent Manner. Shock 2019; 52:240-248. [DOI: 10.1097/shk.0000000000001211] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Assessing the effects of Ang-(1-7) therapy following transient middle cerebral artery occlusion. Sci Rep 2019; 9:3154. [PMID: 30816157 PMCID: PMC6395816 DOI: 10.1038/s41598-019-39102-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 01/15/2019] [Indexed: 11/09/2022] Open
Abstract
The counter-regulatory axis, Angiotensin Converting Enzyme 2, Angiotensin-(1-7), Mas receptor (ACE2/Ang-1-7/MasR), of the renin angiotensin system (RAS) is a potential therapeutic target in stroke, with Ang-(1-7) reported to have neuroprotective effects in pre-clinical stroke models. Here, an extensive investigation of the functional and mechanistic effects of Ang-(1-7) was performed in a rodent model of stroke. Using longitudinal magnetic resonance imaging (MRI) it was observed that central administration of Ang-(1-7) following transient middle cerebral artery occlusion (MCAO) increased the amount of tissue salvage compared to reperfusion alone. This protective effect was not due to early changes in blood brain barrier (BBB) permeability, microglia activation or inflammatory gene expression. However, increases in NADPH oxidase 1 (Nox1) mRNA expression were observed in the treatment group compared to control. In order to determine whether Ang-(1-7) has direct cerebrovascular effects, laser speckle contrast imaging (LSCI) was performed to measure dynamic changes in cortical perfusion following reperfusion. Delivery of Ang-(1-7) did not have any effect on cortical perfusion following reperfusion however; it showed an indication to prevent the 'steal phenomenon' within the contralateral hemisphere. The comprehensive series of studies have demonstrated a moderate protective effect of Ang-(1-7) when given alongside reperfusion to increase tissue salvage.
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16
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Park JE, Jung SC, Kim HS, Suh JY, Baek JH, Woo CW, Park B, Woo DC. Amide proton transfer-weighted MRI can detect tissue acidosis and monitor recovery in a transient middle cerebral artery occlusion model compared with a permanent occlusion model in rats. Eur Radiol 2019; 29:4096-4104. [PMID: 30666450 DOI: 10.1007/s00330-018-5964-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To assess whether increases in amide proton transfer (APT)-weighted signal reflect the effects of tissue recovery from acidosis using transient rat middle cerebral artery occlusion (MCAO) models, compared to permanent occlusion models. MATERIALS AND METHODS Twenty-four rats with MCAO (17 transient and seven permanent occlusions) were prepared. APT-weighted signal (APTw), apparent diffusion coefficient (ADC), cerebral blood flow (CBF), and MR spectroscopy were evaluated at three stages in each group (occlusion, reperfusion/1 h post-occlusion, and 3 h post-reperfusion/4 h post-occlusion). Deficit areas showing 30% reduction to the contralateral side were measured. Temporal changes were compared with repeated measures of analysis of variance. Relationship between APTw and lactate concentration was calculated. RESULTS Both APTw and CBF values increased and APTw deficit area reduced at reperfusion (largest p = .002) in transient occlusion models, but this was not demonstrated in permanent occlusion. No significant temporal change was demonstrated with ADC at reperfusion. APTw deficit area was between ADC and CBF deficit areas in transient occlusion model. APTw correlated with lactate concentration at occlusion (r = - 0.49, p = .04) and reperfusion (r = - 0.32, p = .02). CONCLUSIONS APTw values increased after reperfusion and correlated with lactate content, which suggests that APT-weighted MRI could become a useful imaging technique to reflect tissue acidosis and its reversal. KEY POINTS • APT-weighted signal increases in the tissue reperfusion, while remains stable in the permanent occlusion. • APTw deficit area was between ADC and CBF deficit areas in transient occlusion model, possibly demonstrating metabolic penumbra. • APTw correlated with lactate concentration during ischemia and reperfusion, indicating tissue acidosis.
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Affiliation(s)
- Ji Eun Park
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Seung Chai Jung
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Ho Sung Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea.
| | - Ji-Yeon Suh
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Jin Hee Baek
- University of Ulsan College of Medicine, Asan Medical Center, Seoul, 05505, South Korea
| | - Chul-Woong Woo
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Bumwoo Park
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Dong-Cheol Woo
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
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17
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Chiu FY, Kuo DP, Chen YC, Kao YC, Chung HW, Chen CY. Diffusion Tensor-Derived Properties of Benign Oligemia, True "at Risk" Penumbra, and Infarct Core during the First Three Hours of Stroke Onset: A Rat Model. Korean J Radiol 2018; 19:1161-1171. [PMID: 30386147 PMCID: PMC6201972 DOI: 10.3348/kjr.2018.19.6.1161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/27/2018] [Indexed: 11/15/2022] Open
Abstract
Objective The aim of this study was to investigate diffusion tensor (DT) imaging-derived properties of benign oligemia, true “at risk” penumbra (TP), and the infarct core (IC) during the first 3 hours of stroke onset. Materials and Methods The study was approved by the local animal care and use committee. DT imaging data were obtained from 14 rats after permanent middle cerebral artery occlusion (pMCAO) using a 7T magnetic resonance scanner (Bruker) in room air. Relative cerebral blood flow and apparent diffusion coefficient (ADC) maps were generated to define oligemia, TP, IC, and normal tissue (NT) every 30 minutes up to 3 hours. Relative fractional anisotropy (rFA), pure anisotropy (rq), diffusion magnitude (rL), ADC (rADC), axial diffusivity (rAD), and radial diffusivity (rRD) values were derived by comparison with the contralateral normal brain. Results The mean volume of oligemia was 24.7 ± 14.1 mm3, that of TP was 81.3 ± 62.6 mm3, and that of IC was 123.0 ± 85.2 mm3 at 30 minutes after pMCAO. rFA showed an initial paradoxical 10% increase in IC and TP, and declined afterward. The rq, rL, rADC, rAD, and rRD showed an initial discrepant decrease in IC (from −24% to −36%) as compared with TP (from −7% to −13%). Significant differences (p < 0.05) in metrics, except rFA, were found between tissue subtypes in the first 2.5 hours. The rq demonstrated the best overall performance in discriminating TP from IC (accuracy = 92.6%, area under curve = 0.93) and the optimal cutoff value was −33.90%. The metric values for oligemia and NT remained similar at all time points. Conclusion Benign oligemia is small and remains microstructurally normal under pMCAO. TP and IC show a distinct evolution of DT-derived properties within the first 3 hours of stroke onset, and are thus potentially useful in predicting the fate of ischemic brain.
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Affiliation(s)
- Fang-Ying Chiu
- Department of Medical Imaging and Radiological Sciences, College of Medicine, I-Shou University, Kaohsiung 82445, Taiwan
| | - Duen-Pang Kuo
- Department of Radiology, Taoyuan Armed Forces General Hospital, Taoyuan 32551, Taiwan
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan.,Translational Imaging Research Center, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Yu-Chieh Kao
- Translational Imaging Research Center, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electrics and Bioinformatics, National Taiwan. University, Taipei 10617, Taiwan
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan.,Translational Imaging Research Center, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.,Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.,Department of Radiology, Tri-Service General Hospital, Taipei 11490, Taiwan.,Department of Radiology, National Defense Medical Center, Taipei 11490, Taiwan
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18
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Thow LA, MacDonald K, Holmes WM, Muir KW, Macrae IM, Dewar D. Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats. Brain Neurosci Adv 2018; 2:2398212818794820. [PMID: 32166145 PMCID: PMC7058243 DOI: 10.1177/2398212818794820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Background: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. Methods: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. Results: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. Conclusions: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear.
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Affiliation(s)
- Lisa A Thow
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Kathleen MacDonald
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Keith W Muir
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Deborah Dewar
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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19
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Choi CH, Yi KS, Lee SR, Lee Y, Jeon CY, Hwang J, Lee C, Choi SS, Lee HJ, Cha SH. A novel voxel-wise lesion segmentation technique on 3.0-T diffusion MRI of hyperacute focal cerebral ischemia at 1 h after permanent MCAO in rats. J Cereb Blood Flow Metab 2018; 38:1371-1383. [PMID: 28598225 PMCID: PMC6092770 DOI: 10.1177/0271678x17714179] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To assess hyperacute focal cerebral ischemia in rats on 3.0-Tesla diffusion-weighted imaging (DWI), we developed a novel voxel-wise lesion segmentation technique that overcomes intra- and inter-subject variation in apparent diffusion coefficient (ADC) distribution. Our novel technique involves the following: (1) intensity normalization including determination of the optimal type of region of interest (ROI) and its intra- and inter-subject validation, (2) verification of focal cerebral ischemic lesions at 1 h with gross and high-magnification light microscopy of hematoxylin-eosin (H&E) pathology, (3) voxel-wise segmentation on ADC with various thresholds, and (4) calculation of dice indices (DIs) to compare focal cerebral ischemic lesions at 1 h defined by ADC and matching H&E pathology. The best coefficient of variation was the mode of the left hemisphere after normalization using whole left hemispheric ROI, which showed lower intra- (2.54 ± 0.72%) and inter-subject (2.67 ± 0.70%) values than the original. Focal ischemic lesion at 1 h after middle cerebral artery occlusion (MCAO) was confirmed on both gross and microscopic H&E pathology. The 83 relative threshold of normalized ADC showed the highest mean DI (DI = 0.820 ± 0.075). We could evaluate hyperacute ischemic lesions at 1 h more reliably on 3-Tesla DWI in rat brains.
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Affiliation(s)
- Chi-Hoon Choi
- 1 Department of Radiology, Chungbuk National University Hospital, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Kyung Sik Yi
- 1 Department of Radiology, Chungbuk National University Hospital, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Sang-Rae Lee
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Youngjeon Lee
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Chang-Yeop Jeon
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Jinwoo Hwang
- 3 Clinical Science, Philips Healthcare, Seoul, Republic of Korea
| | - Chulhyun Lee
- 4 Bioimaging Research Team, Korea Basic Science Institute, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Sung Sik Choi
- 5 Medical Research Institute, Chung-Ang University, Seoul, Republic of Korea
| | - Hong Jun Lee
- 5 Medical Research Institute, Chung-Ang University, Seoul, Republic of Korea
| | - Sang-Hoon Cha
- 1 Department of Radiology, Chungbuk National University Hospital, Cheongju-si, Chungcheongbuk-do, Republic of Korea.,6 College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju-si, Chungcheongbuk-do, Republic of Korea
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20
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Animal models of ischaemic stroke and characterisation of the ischaemic penumbra. Neuropharmacology 2017; 134:169-177. [PMID: 28923277 DOI: 10.1016/j.neuropharm.2017.09.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/08/2017] [Accepted: 09/13/2017] [Indexed: 02/07/2023]
Abstract
Over the past forty years, animal models of focal cerebral ischaemia have allowed us to identify the critical cerebral blood flow thresholds responsible for irreversible cell death, electrical failure, inhibition of protein synthesis, energy depletion and thereby the lifespan of the potentially salvageable penumbra. They have allowed us to understand the intricate biochemical and molecular mechanisms within the 'ischaemic cascade' that initiate cell death in the first minutes, hours and days following stroke. Models of permanent, transient middle cerebral artery occlusion and embolic stroke have been developed each with advantages and limitations when trying to model the complex heterogeneous nature of stroke in humans. Yet despite these advances in understanding the pathophysiological mechanisms of stroke-induced cell death with numerous targets identified and drugs tested, a lack of translation to the clinic has hampered pre-clinical stroke research. With recent positive clinical trials of endovascular thrombectomy in acute ischaemic stroke the stroke community has been reinvigorated, opening up the potential for future translation of adjunctive treatments that can be given alongside thrombectomy/thrombolysis. This review discusses the major animal models of focal cerebral ischaemia highlighting their advantages and limitations. Acute imaging is crucial in longitudinal pre-clinical stroke studies in order to identify the influence of acute therapies on tissue salvage over time. Therefore, the methods of identifying potentially salvageable ischaemic penumbra are discussed. This article is part of the Special Issue entitled 'Cerebral Ischemia'.
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21
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Tiwari YV, Lu J, Shen Q, Cerqueira B, Duong TQ. Magnetic resonance imaging of blood-brain barrier permeability in ischemic stroke using diffusion-weighted arterial spin labeling in rats. J Cereb Blood Flow Metab 2017; 37:2706-2715. [PMID: 27742887 PMCID: PMC5536782 DOI: 10.1177/0271678x16673385] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 09/02/2016] [Accepted: 09/13/2016] [Indexed: 12/25/2022]
Abstract
Diffusion-weighted arterial spin labeling magnetic resonance imaging has recently been proposed to quantify the rate of water exchange (Kw) across the blood-brain barrier in humans. This study aimed to evaluate the blood-brain barrier disruption in transient (60 min) ischemic stroke using Kw magnetic resonance imaging with cross-validation by dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology in the same rats. The major findings were: (i) at 90 min after stroke (30 min after reperfusion), group Kw magnetic resonance imaging data showed no significant blood-brain barrier permeability changes, although a few animals showed slightly abnormal Kw. Dynamic contrast-enhanced magnetic resonance imaging confirmed this finding in the same animals. (ii) At two days after stroke, Kw magnetic resonance imaging revealed significant blood-brain barrier disruption. Regions with abnormal Kw showed substantial overlap with regions of hyperintense T2 (vasogenic edema) and hyperperfusion. Dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology confirmed these findings in the same animals. The Kw values in the normal contralesional hemisphere and the ipsilesional ischemic core two days after stroke were: 363 ± 17 and 261 ± 18 min-1, respectively (P < 0.05, n = 9). Kw magnetic resonance imaging is sensitive to blood-brain barrier permeability changes in stroke, consistent with dynamic contrast-enhanced magnetic resonance imaging and Evans blue extravasation. Kw magnetic resonance imaging offers advantages over existing techniques because contrast agent is not needed and repeated measurements can be made for longitudinal monitoring or averaging.
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Affiliation(s)
- Yash V Tiwari
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Biomedical Engineering, University of Texas at San Antonio, TX, USA
| | - Jianfei Lu
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Bianca Cerqueira
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Biomedical Engineering, University of Texas at San Antonio, TX, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
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22
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Yi KS, Choi CH, Lee SR, Lee HJ, Lee Y, Jeong KJ, Hwang J, Chang KT, Cha SH. Sustained diffusion reversal with in-bore reperfusion in monkey stroke models: Confirmed by prospective magnetic resonance imaging. J Cereb Blood Flow Metab 2017; 37:2002-2012. [PMID: 27401804 PMCID: PMC5464696 DOI: 10.1177/0271678x16659302] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Although early diffusion lesion reversal after recanalization treatment of acute ischaemic stroke has been observed in clinical settings, the reversibility of lesions observed by diffusion-weighted imaging remains controversial. Here, we present consistent observations of sustained diffusion lesion reversal after transient middle cerebral artery occlusion in a monkey stroke model. Seven rhesus macaques were subjected to endovascular transient middle cerebral artery occlusion with in-bore reperfusion confirmed by repeated prospective diffusion-weighted imaging. Early diffusion lesion reversal was defined as lesion reversal at 3 h after reperfusion. Sustained diffusion lesion reversal was defined as the difference between the ADC-derived pre-reperfusion maximal ischemic lesion volume (ADCD-P Match) and the lesion on 4-week follow-up FLAIR magnetic resonance imaging. Diffusion lesions were spatiotemporally assessed using a 3-D voxel-based quantitative technique. The ADCD-P Match was 9.7 ± 6.0% (mean ± SD) and the final infarct was 1.2-6.0% of the volume of the ipsilateral hemisphere. Early diffusion lesion reversal and sustained diffusion lesion reversal were observed in all seven animals, and the calculated percentages compared with their ADCD-P Match ranged from 8.3 to 51.9% (mean ± SD, 26.9 ± 15.3%) and 41.7-77.8% (mean ± SD, 65.4 ± 12.2%), respectively. Substantial sustained diffusion lesion reversal and early reversal were observed in all animals in this monkey model of transient focal cerebral ischaemia.
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Affiliation(s)
- Kyung Sik Yi
- 1 Department of Radiology, Chungbuk National University Hospital, Chungbuk, Republic of Korea
| | - Chi-Hoon Choi
- 1 Department of Radiology, Chungbuk National University Hospital, Chungbuk, Republic of Korea
| | - Sang-Rae Lee
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, Republic of Korea
| | - Hong Jun Lee
- 3 Medical Research Institute, Chung-Ang University, Seoul, Korea
| | - Youngjeon Lee
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, Republic of Korea
| | - Kang-Jin Jeong
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, Republic of Korea
| | - Jinwoo Hwang
- 4 Clinical Science, Philips Healthcare, Seoul, Republic of Korea
| | - Kyu-Tae Chang
- 2 National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, Republic of Korea
| | - Sang-Hoon Cha
- 1 Department of Radiology, Chungbuk National University Hospital, Chungbuk, Republic of Korea.,5 College of Medicine, Chungbuk National University, Chungbuk, Republic of Korea
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23
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Cuccione E, Versace A, Cho TH, Carone D, Berner LP, Ong E, Rousseau D, Cai R, Monza L, Ferrarese C, Sganzerla EP, Berthezène Y, Nighoghossian N, Wiart M, Beretta S, Chauveau F. Multi-site laser Doppler flowmetry for assessing collateral flow in experimental ischemic stroke: Validation of outcome prediction with acute MRI. J Cereb Blood Flow Metab 2017; 37:2159-2170. [PMID: 27466372 PMCID: PMC5464709 DOI: 10.1177/0271678x16661567] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
High variability in infarct size is common in experimental stroke models and affects statistical power and validity of neuroprotection trials. The aim of this study was to explore cerebral collateral flow as a stratification factor for the prediction of ischemic outcome. Transient intraluminal occlusion of the middle cerebral artery was induced for 90 min in 18 Wistar rats. Cerebral collateral flow was assessed intra-procedurally using multi-site laser Doppler flowmetry monitoring in both the lateral middle cerebral artery territory and the borderzone territory between middle cerebral artery and anterior cerebral artery. Multi-modal magnetic resonance imaging was used to assess acute ischemic lesion (diffusion-weighted imaging, DWI), acute perfusion deficit (time-to-peak, TTP), and final ischemic lesion at 24 h. Infarct volumes and typology at 24 h (large hemispheric versus basal ganglia infarcts) were predicted by both intra-ischemic collateral perfusion and acute DWI lesion volume. Collateral flow assessed by multi-site laser Doppler flowmetry correlated with the corresponding acute perfusion deficit using TTP maps. Multi-site laser Doppler flowmetry monitoring was able to predict ischemic outcome and perfusion deficit in good agreement with acute MRI. Our results support the additional value of cerebral collateral flow monitoring for outcome prediction in experimental ischemic stroke, especially when acute MRI facilities are not available.
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Affiliation(s)
- Elisa Cuccione
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy.,2 PhD Program in Neuroscience, University of Milano-Bicocca, Monza, Italy
| | - Alessandro Versace
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy
| | - Tae-Hee Cho
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France.,4 Hospices Civils de Lyon, France
| | - Davide Carone
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy
| | - Lise-Prune Berner
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France.,4 Hospices Civils de Lyon, France
| | - Elodie Ong
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France.,4 Hospices Civils de Lyon, France
| | - David Rousseau
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France
| | - Ruiyao Cai
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy
| | - Laura Monza
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy
| | - Carlo Ferrarese
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy.,5 Milan Center for Neuroscience (NeuroMi), Milan, Italy
| | - Erik P Sganzerla
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy.,5 Milan Center for Neuroscience (NeuroMi), Milan, Italy
| | - Yves Berthezène
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France.,4 Hospices Civils de Lyon, France
| | - Norbert Nighoghossian
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France.,4 Hospices Civils de Lyon, France
| | - Marlène Wiart
- 3 Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1, Lyon, France
| | - Simone Beretta
- 1 Department of Medicine and Surgery, Laboratory of Experimental Stroke Research, University of Milano-Bicocca, Monza, Italy.,5 Milan Center for Neuroscience (NeuroMi), Milan, Italy
| | - Fabien Chauveau
- 6 Université de Lyon, Lyon Neuroscience Research Center, BioRaN team; CNRS UMR5292; Inserm U1028; Université Lyon 1, Lyon, France
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24
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Boisserand LSB, Lemasson B, Hirschler L, Moisan A, Hubert V, Barbier EL, Rémy C, Detante O. Multiparametric magnetic resonance imaging including oxygenation mapping of experimental ischaemic stroke. J Cereb Blood Flow Metab 2017; 37:2196-2207. [PMID: 27466373 PMCID: PMC5464712 DOI: 10.1177/0271678x16662044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent advances in MRI methodology, such as microvascular and brain oxygenation (StO2) imaging, may prove useful in obtaining information about the severity of the acute stroke. We assessed the potential of StO2 to detect the ischaemic core in the acute phase compared to apparent diffusion coefficient and to predict the final necrosis. Sprague-Dawley rats (n = 38) were imaged during acute stroke (D0) and 21 days after (D21). A multiparametric MRI protocol was performed at 4.7T to characterize brain damage within three region of interest: 'LesionD0' (diffusion), 'Mismatch' representing penumbra (perfusion/diffusion) and 'Hypoxia' (voxels < 40% of StO2 within the region of interest LesionD0). Voxel-based analysis of stroke revealed heterogeneity of the region of interest LesionD0, which included voxels with different degrees of oxygenation decrease. This finding was supported by a dramatic decrease of vascular and perfusion parameters within the region of interest hypoxia. This zone presented the lowest values of almost all parameters analysed, indicating a higher severity. Our study demonstrates the potential of StO2 magnetic resonance imaging to more accurately detect the ischaemic core without the inclusion of any reversible ischaemic damage. Our follow-up study indicates that apparent diffusion coefficient imaging overestimated the final necrosis while StO2 imaging did not.
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Affiliation(s)
- Ligia Simões Braga Boisserand
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,3 CAPES Foundation, Ministry of Education of Brazil, Brasilia, Brazil
| | - Benjamin Lemasson
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Lydiane Hirschler
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,4 Bruker Biospin, Ettlingen, Germany
| | - Anaïck Moisan
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,5 Cell Therapy and Engineering Unit, EFS Rhône Alpes, Saint Ismier, France
| | - Violaine Hubert
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France
| | - Emmanuel L Barbier
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Chantal Rémy
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Olivier Detante
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,6 CHU Grenoble Alpes, Grenoble, France
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25
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Wang S, Gu X, Paudyal R, Wei L, Dix TA, Yu SP, Zhang X. Longitudinal MRI evaluation of neuroprotective effects of pharmacologically induced hypothermia in experimental ischemic stroke. Magn Reson Imaging 2017; 40:24-30. [PMID: 28377304 DOI: 10.1016/j.mri.2017.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/07/2017] [Accepted: 03/30/2017] [Indexed: 01/21/2023]
Abstract
Pharmacologically induced hypothermia (PIH) shows promising neuroprotective effects after stroke insult. However, the dynamic evolution of stroke infarct during the hypothermic therapy has not been understood very well. In the present study, MRI was utilized to longitudinally characterize the infarct evolution in a mouse model of ischemic stroke treated by PIH using the neurotensin agonist HPI201. Adult male C57BL/6 mice underwent permanent occlusion of the right middle cerebra artery (MCA). Each animal received a vehicle or HPI201 intraperitoneal injection. The temporal changes of stroke lesion were examined using T2-weighted imaging and diffusion-weighted imaging (DWI) in the acute phase (1-3h) and 24h post stroke. Significantly reduced infarct and edema volumes were observed in PIH treated stroke mice, in agreement with TTC staining findings. Also, the TUNEL staining results indicated apoptotic cells were widely distributed among the ischemic cortex in control group but limited in PIH treated mice. Dramatically reduced growth rate of infarction was seen in PIH treated stroke mice. These results demonstrate HPI201 has strong neuroprotection effects during acute stroke. In particular, MRI with the numerical modelling of temporal infarct evolution could provide a unique means to examine and predict the dynamic response of the PIH treatment on infarct evolution.
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Affiliation(s)
- Silun Wang
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Xiaohuan Gu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Ramesh Paudyal
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, United States
| | - Ling Wei
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Thomas A Dix
- Department of Drug Discovery Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, United States; JT Pharmaceuticals Inc., Mt. Pleasant, SC 29464, United States
| | - Shan P Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA 30322, United States; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA 30033, United States.
| | - Xiaodong Zhang
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States.
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26
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Kuo DP, Lu CF, Liou M, Chen YC, Chung HW, Chen CY. Differentiation of the Infarct Core from Ischemic Penumbra within the First 4.5 Hours, Using Diffusion Tensor Imaging-Derived Metrics: A Rat Model. Korean J Radiol 2017; 18:269-278. [PMID: 28246507 PMCID: PMC5313515 DOI: 10.3348/kjr.2017.18.2.269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 09/02/2016] [Indexed: 12/21/2022] Open
Abstract
Objective To investigate whether the diffusion tensor imaging-derived metrics are capable of differentiating the ischemic penumbra (IP) from the infarct core (IC), and determining stroke onset within the first 4.5 hours. Materials and Methods All procedures were approved by the local animal care committee. Eight of the eleven rats having permanent middle cerebral artery occlusion were included for analyses. Using a 7 tesla magnetic resonance system, the relative cerebral blood flow and apparent diffusion coefficient maps were generated to define IP and IC, half hour after surgery and then every hour, up to 6.5 hours. Relative fractional anisotropy, pure anisotropy (rq) and diffusion magnitude (rL) maps were obtained. One-way analysis of variance, receiver operating characteristic curve and nonlinear regression analyses were performed. Results The evolutions of tensor metrics were different in ischemic regions (IC and IP) and topographic subtypes (cortical, subcortical gray matter, and white matter). The rL had a significant drop of 40% at 0.5 hour, and remained stagnant up to 6.5 hours. Significant differences (p < 0.05) in rL values were found between IP, IC, and normal tissue for all topographic subtypes. Optimal rL threshold in discriminating IP from IC was about -29%. The evolution of rq showed an exponential decrease in cortical IC, from -26.9% to -47.6%; an rq reduction smaller than 44.6% can be used to predict an acute stroke onset in less than 4.5 hours. Conclusion Diffusion tensor metrics may potentially help discriminate IP from IC and determine the acute stroke age within the therapeutic time window.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan.; Department of Radiology, Taoyuan Armed Forces General Hospital, Taoyuan 32551, Taiwan
| | - Chia-Feng Lu
- Research Center of Translational Imaging, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan.; Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei 112, Taiwan
| | - Michelle Liou
- Institute of Statistical Science, Academia Sinica, Taipei 11529, Taiwan
| | - Yung-Chieh Chen
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electrics and Bioinformatics, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Yu Chen
- Research Center of Translational Imaging, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.; Department of Medical Imaging and Imaging Research Center, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan.; Department of Radiology, Tri-Service General Hospital, Taipei 114, Taiwan.; Department of Radiology, National Defense Medical Center, Taipei 114, Taiwan
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27
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Cardenas DP, Muir ER, Duong TQ. MRI of cerebral blood flow under hyperbaric conditions in rats. NMR IN BIOMEDICINE 2016; 29:961-968. [PMID: 27192391 PMCID: PMC4998963 DOI: 10.1002/nbm.3555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/03/2016] [Accepted: 04/11/2016] [Indexed: 06/05/2023]
Abstract
Hyperbaric oxygen (HBO) therapy has a number of clinical applications. However, the effects of acute HBO on basal cerebral blood flow (CBF) and neurovascular coupling are not well understood. This study explored the use of arterial spin labeling MRI to evaluate changes in baseline and forepaw stimulus-evoked CBF responses in rats (n = 8) during normobaric air (NB), normobaric oxygen (NBO) (100% O2 ), 3 atm absolute (ATA) hyperbaric air (HB) and 3 ATA HBO conditions. T1 was also measured, and the effects of changes in T1 caused by increasing oxygen on the CBF calculation were investigated. The major findings were as follows: (i) increased inhaled oxygen concentrations led to a reduced respiration rate; (ii) increased dissolved paramagnetic oxygen had significant effects on blood and tissue T1 , which affected the CBF calculation using the arterial spin labeling method; (iii) the differences in blood T1 had a larger effect than the differences in tissue T1 on CBF calculation; (iv) if oxygen-induced changes in blood and tissue T1 were not taken into account, CBF was underestimated by 33% at 3 ATA HBO, 10% at NBO and <5% at HB; (v) with correction, CBF values under HBO, HB and NBO were similar (p > 0.05) and all were higher than CBF under NB by ~40% (p < 0.05), indicating that hypercapnia from the reduced respiration rate masks oxygen-induced vasoconstriction, although blood gas was not measured; and (vi) substantial stimulus-evoked CBF increases were detected under HBO, similar to NB, supporting the notion that activation-induced CBF regulation in the brain does not operate through an oxygen-sensing mechanism. CBF MRI provides valuable insights into the effects of oxygen on basal CBF and neurovascular coupling under hyperbaric conditions. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Damon P. Cardenas
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Graduate School of Biomedical Science, University of Texas at San Antonio, San Antonio, TX, USA
| | - Eric R. Muir
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Timothy Q. Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, TX, USA
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28
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Rodriguez P, Zhao J, Milman B, Tiwari YV, Duong TQ. Methylene blue and normobaric hyperoxia combination therapy in experimental ischemic stroke. Brain Behav 2016; 6:e00478. [PMID: 27458543 PMCID: PMC4951618 DOI: 10.1002/brb3.478] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/11/2016] [Accepted: 03/18/2016] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Ischemic stroke is a global burden that contributes to the disability and mortality of millions of patients. This study aimed to evaluate the efficacy of combined MB (methylene blue) and NBO (normobaric hyperoxia) therapy in experimental ischemic stroke. METHODS Rats with transient (60 min) MCAO (middle cerebral artery occlusion) were treated with: (1) air + vehicle (N = 8), (2) air + MB (N = 8), (3) NBO + vehicle (N = 7), and (4) NBO + MB (N = 9). MB (1 mg/kg) was administered at 30 min, again on days 2, 7, and 14 after stroke. NBO was given during MRI (30-150 min) on day 0, and again 1 h each during MRI on subsequent days. Serial diffusion, perfusion and T2 MRI were performed to evaluate lesion volumes. Foot-fault and cylinder tests were performed to evaluate sensorimotor function. RESULTS The major findings were: (1) NBO + MB therapy showed a greater decrease in infarct volume compared to NBO alone, but similar infarct volume compared to MB alone, (2) NBO + MB therapy accelerated sensorimotor functional recovery compared to NBO or MB alone, (3) Infarct volumes on day 2 did not change significantly from those on day 28 for all four groups, but behavioral function continued to show improved recovery in the NBO + MB group. CONCLUSIONS These findings support the hypothesis that combined NBO + MB further improves functional outcome and reduces infarct volume compared to either treatment alone and these improvements extended up to 28 days.
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Affiliation(s)
- Pavel Rodriguez
- Research Imaging InstituteUniversity of Texas Health Science CenterSan AntonioTexas
- Department of RadiologyUniversity of Texas Health Science CenterSan AntonioTexas
| | - Jiang Zhao
- Research Imaging InstituteUniversity of Texas Health Science CenterSan AntonioTexas
- Department of Anatomy and EmbryologyPeking University Health Science CenterBeijingChina
| | - Brian Milman
- Research Imaging InstituteUniversity of Texas Health Science CenterSan AntonioTexas
| | - Yash Vardhan Tiwari
- Research Imaging InstituteUniversity of Texas Health Science CenterSan AntonioTexas
- Department of Biomedical EngineeringUniversity of TexasSan AntonioTexas
| | - Timothy Q. Duong
- Research Imaging InstituteUniversity of Texas Health Science CenterSan AntonioTexas
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29
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Chandra SB, Mohan S, Ford BM, Huang L, Janardhanan P, Deo KS, Cong L, Muir ER, Duong TQ. Targeted overexpression of endothelial nitric oxide synthase in endothelial cells improves cerebrovascular reactivity in Ins2Akita-type-1 diabetic mice. J Cereb Blood Flow Metab 2016; 36:1135-42. [PMID: 26661212 PMCID: PMC4908624 DOI: 10.1177/0271678x15612098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/23/2015] [Indexed: 11/16/2022]
Abstract
Reduced bioavailability of nitric oxide due to impaired endothelial nitric oxide synthase (eNOS) activity is a leading cause of endothelial dysfunction in diabetes. Enhancing eNOS activity in diabetes is a potential therapeutic target. This study investigated basal cerebral blood flow and cerebrovascular reactivity in wild-type mice, diabetic mice (Ins2(Akita+/-)), nondiabetic eNOS-overexpressing mice (TgeNOS), and the cross of two transgenic mice (TgeNOS-Ins2(Akita+/-)) at six months of age. The cross was aimed at improving eNOS expression in diabetic mice. The major findings were: (i) Body weights of Ins2(Akita+/-) and TgeNOS-Ins2(Akita+/-) were significantly different from wild-type and TgeNOS mice. Blood pressure of TgeNOS mice was lower than wild-type. (ii) Basal cerebral blood flow of the TgeNOS group was significantly higher than cerebral blood flow of the other three groups. (iii) The cerebrovascular reactivity in the Ins2(Akita+/-) mice was significantly lower compared with wild-type, whereas that in the TgeNOS-Ins2(Akita+/-) was significantly higher compared with the Ins2(Akita+/-) and TgeNOS groups. Overexpression of eNOS rescued cerebrovascular dysfunction in diabetic animals, resulting in improved cerebrovascular reactivity. These results underscore the possible role of eNOS in vascular dysfunction in the brain of diabetic mice and support the notion that enhancing eNOS activity in diabetes is a potential therapeutic target.
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Affiliation(s)
- Saurav B Chandra
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Sumathy Mohan
- Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Bridget M Ford
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Lei Huang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Preethi Janardhanan
- Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Kaiwalya S Deo
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Linlin Cong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Eric R Muir
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
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Li W, Watts L, Long J, Zhou W, Shen Q, Jiang Z, Li Y, Duong TQ. Spatiotemporal changes in blood-brain barrier permeability, cerebral blood flow, T2 and diffusion following mild traumatic brain injury. Brain Res 2016; 1646:53-61. [PMID: 27208495 DOI: 10.1016/j.brainres.2016.05.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/12/2016] [Accepted: 05/18/2016] [Indexed: 12/21/2022]
Abstract
The blood-brain barrier (BBB) can be impaired following traumatic brain injury (TBI), however the spatiotemporal dynamics of BBB leakage remain incompletely understood. In this study, we evaluated the spatiotemporal evolution of BBB permeability using dynamic contrast-enhanced MRI and measured the volume transfer coefficient (K(trans)), a quantitative measure of contrast agent leakage across the blood and extravascular compartment. Measurements were made in a controlled cortical impact (CCI) model of mild TBI in rats from 1h to 7 days following TBI. The results were compared with cerebral blood flow, T2 and diffusion MRI from the same animal. Spatially, K(trans) changes were localized to superficial cortical layers within a 1mm thickness, which was dramatically different from the changes in cerebral blood flow, T2 and diffusion, which were localized to not only the superficial layers but also to brain regions up to 2.2mm from the cortical surface. Temporally, K(trans) changes peaked at day 3, similar to CBF and ADC changes, but differed from T2 and FA, whose changes peaked on day 2. The pattern of superficial cortical layer localization of K(trans) was consistent with patterns revealed by Evans Blue extravasation. Collectively, these results suggest that BBB disruption, edema formation, blood flow disturbance and diffusion changes are related to different components of the mechanical impact, and may play different roles in determining injury progression and tissue fate processes following TBI.
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Affiliation(s)
- Wei Li
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Lora Watts
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Neurology, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Justin Long
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Wei Zhou
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Zhao Jiang
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Yunxia Li
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX 78229, USA; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, TX 78229, USA.
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31
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Tiwari YV, Jiang Z, Sun Y, Du F, Rodriguez P, Shen Q, Duong TQ. Effects of stroke severity and treatment duration in normobaric hyperoxia treatment of ischemic stroke. Brain Res 2016; 1635:121-9. [PMID: 26826010 PMCID: PMC4779399 DOI: 10.1016/j.brainres.2016.01.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 11/26/2022]
Abstract
In order to improve clinical trial design and translation of normobaric oxygen (NBO) treatment of ischemic stroke, NBO treatment parameters need to be better understood. This study investigated NBO treatment efficacy at two different stroke severities and two NBO treatment durations in rats. For the 60-min middle cerebral artery occlusion (MCAO), NBO treatment for 25 min and 150 min were studied. For the 90-min MCAO, NBO treatment for 55 min and 150 min were studied. Cerebral blood flow (CBF), apparent diffusion coefficients (ADC) and T2 MRI were acquired during occlusion prior to treatment, after reperfusion, and 48h after MCAO. The effects of NBO treatment on lesion volumes, and CBF, ADC and T2 of ischemic core, perfusion-diffusion mismatch and normal tissue were analyzed longitudinally. The major findings were: i) NBO treatment was effective in both groups of stroke severities, salvaging similar percentage of initial abnormal ADC tissue, and ii) NBO treatments continued after reperfusion were more beneficial than NBO treatment during occlusion alone for both MCAO groups. These findings underscore the importance of the effects of NBO duration and stroke severity on treatment outcomes.
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Affiliation(s)
- Yash Vardhan Tiwari
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA; Department of Biomedical Engineering, University of Texas, San Antonio, TX, USA
| | - Zhao Jiang
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Yuhao Sun
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Fang Du
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Pavel Rodriguez
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX 78229, USA.
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Abstract
Perfusion could provide useful information on the metabolic status and functional status of tissues and organs. This review summarizes the most commonly used perfusion measurement methods: Dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) and their applications in experimental stroke. Some new developments of cerebral blood flow (CBF) techniques in animal models are also discussed.
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Affiliation(s)
- Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA; Department of Ophthalmology, University of Texas Health Science Center, San Antonio, Texas, USA; Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA; Department of Ophthalmology, University of Texas Health Science Center, San Antonio, Texas, USA; Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, Texas, USA
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33
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Sun Y, Shen Q, Watts LT, Muir ER, Huang S, Yang GY, Suarez JI, Duong TQ. Multimodal MRI characterization of experimental subarachnoid hemorrhage. Neuroscience 2016; 316:53-62. [PMID: 26708744 PMCID: PMC4724533 DOI: 10.1016/j.neuroscience.2015.12.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/10/2015] [Accepted: 12/14/2015] [Indexed: 01/01/2023]
Abstract
Subarachnoid hemorrhage (SAH) is associated with significant morbidity and mortality. We implemented an in-scanner rat model of mild SAH in which blood or vehicle was injected into the cistern magna, and applied multimodal MRI to study the brain prior to, immediately after (5min to 4h), and upto 7days after SAH. Vehicle injection did not change arterial lumen diameter, apparent diffusion coefficient (ADC), T2, venous signal, vascular reactivity to hypercapnia, or foot-fault scores, but mildly reduce cerebral blood flow (CBF) up to 4h, and open-field activity up to 7days post injection. By contrast, blood injection caused: (i) vasospasm 30min after SAH but not thereafter, (ii) venous abnormalities at 3h and 2days, delayed relative to vasospasm, (iii) reduced basal CBF and to hypercapnia 1-4h but not thereafter, (iv) reduced ADC immediately after SAH but no ADC and T2 changes on days 2 and 7, and (v) reduced open-field activities in both SAH and vehicle animals, but no significant differences in open-field activities and foot-fault tests between groups. Mild SAH exhibited transient and mild hemodynamic disturbances and diffusion changes, but did not show apparent ischemic brain injury nor functional deficits.
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Affiliation(s)
- Y Sun
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Department of Stereotactic and Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Q Shen
- Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - L T Watts
- Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Neurology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - E R Muir
- Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - S Huang
- Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - G-Y Yang
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Department of Stereotactic and Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Neuroscience and Neuroengineering Research Center, Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - J I Suarez
- Division of Vascular Neurology and Neurocritical Care, Department of Neurology, Baylor College of Medicine, Baylor St Luke's Medical Center, Houston, TX 77027, USA
| | - T Q Duong
- Research Imaging Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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Baskerville TA, Macrae IM, Holmes WM, McCabe C. The influence of gender on 'tissue at risk' in acute stroke: A diffusion-weighted magnetic resonance imaging study in a rat model of focal cerebral ischaemia. J Cereb Blood Flow Metab 2016; 36:381-6. [PMID: 26661149 PMCID: PMC4759665 DOI: 10.1177/0271678x15606137] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/31/2015] [Indexed: 11/17/2022]
Abstract
This is the first study to assess the influence of sex on the evolution of ischaemic injury and penumbra. Permanent middle cerebral artery occlusion was induced in male (n = 9) and female (n = 10) Sprague-Dawley rats. Diffusion-weighted imaging was acquired over 4 h and infarct determined from T2 images at 24 h post-permanent middle cerebral artery occlusion. Penumbra was determined retrospectively from serial apparent diffusion coefficient lesions and T2-defined infarct. Apparent diffusion coefficient lesion volume was significantly smaller in females from 0.5 to 4 h post permanent middle cerebral artery occlusion as was infarct volume. Penumbral volume, and its loss over time, was not significantly different despite the sex difference in acute and final lesion volumes.
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Affiliation(s)
- Tracey A Baskerville
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - Christopher McCabe
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
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Shen Q, Huang S, Duong TQ. T2*-weighted fMRI time-to-peak of oxygen challenge in ischemic stroke. J Cereb Blood Flow Metab 2016; 36:283-91. [PMID: 26661164 PMCID: PMC4759668 DOI: 10.1177/0271678x15606461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/11/2015] [Indexed: 11/16/2022]
Abstract
T2 (*)-weighted MRI of transient oxygen challenge (OC) showed exaggerated OC percent changes in the ischemic tissue at risk compared to normal tissue. One ambiguity is that regions with high vascular density also showed exaggerated OC percent changes. This study explored time-to-peak (TTP) of the OC percent changes to improve the utility of T2 (*)-weighted OC MRI. Experiments were performed longitudinally at 30 min, 150 min and 24 h after transient (60-min) stroke in rats. Ischemic core, normal, and mismatch tissue were classified pixel-by-pixel based on apparent diffusion coefficient and cerebral blood flow. Major findings were: (i) Delayed OC TTP was localized to and corresponded well with the perfusion-diffusion mismatch. (ii) By contrast, the exaggerated OC percent changes were less localized, with changes not only in the at-risk tissue but also in some areas of the contralesional hemisphere with venous vessel origins. (iii) The OC time-course of the mismatch tissue was biphasic, with a faster initial increase followed by a slower increase. (iv) At-risk tissue with delayed TTP and exaggerated OC was normal after reperfusion and the at-risk tissue was mostly (83 ± 18%) rescued by reperfusion as indicated by normal 24-h T2. OC TTP offers unique information toward better characterization of at-risk tissue in ischemic stroke.
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Affiliation(s)
- Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA Department of Radiology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA Department of Radiology, University of Texas Health Science Center, San Antonio, TX, USA South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, TX, USA
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36
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Shen Q, Watts LT, Li W, Duong TQ. Magnetic Resonance Imaging in Experimental Traumatic Brain Injury. Methods Mol Biol 2016; 1462:645-58. [PMID: 27604743 DOI: 10.1007/978-1-4939-3816-2_35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability in the USA. Common causes of TBI include falls, violence, injuries from wars, and vehicular and sporting accidents. The initial direct mechanical damage in TBI is followed by progressive secondary injuries such as brain swelling, perturbed cerebral blood flow (CBF), abnormal cerebrovascular reactivity (CR), metabolic dysfunction, blood-brain-barrier disruption, inflammation, oxidative stress, and excitotoxicity, among others. Magnetic resonance imaging (MRI) offers the means to noninvasively probe many of these secondary injuries. MRI has been used to image anatomical, physiological, and functional changes associated with TBI in a longitudinal manner. This chapter describes controlled cortical impact (CCI) TBI surgical procedures, a few common MRI protocols used in TBI imaging, and, finally, image analysis pertaining to experimental TBI imaging in rats.
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Affiliation(s)
- Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX, 78229, USA. .,Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA. .,Department of Radiology, University of Texas Health Science Center, San Antonio, TX, USA.
| | - Lora Tally Watts
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX, 78229, USA.,Departments of Cellular and Structure Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Wei Li
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX, 78229, USA.,Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, 8403 Floyd Curl Dr, San Antonio, TX, 78229, USA. .,Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA. .,Department of Radiology, University of Texas Health Science Center, San Antonio, TX, USA. .,Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, TX, USA.
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Long JA, Watts LT, Li W, Shen Q, Muir ER, Huang S, Boggs RC, Suri A, Duong TQ. The effects of perturbed cerebral blood flow and cerebrovascular reactivity on structural MRI and behavioral readouts in mild traumatic brain injury. J Cereb Blood Flow Metab 2015; 35:1852-61. [PMID: 26104285 PMCID: PMC4635242 DOI: 10.1038/jcbfm.2015.143] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 05/11/2015] [Accepted: 05/22/2015] [Indexed: 12/22/2022]
Abstract
This study investigated the effects of perturbed cerebral blood flow (CBF) and cerebrovascular reactivity (CR) on relaxation time constant (T2), apparent diffusion coefficient (ADC), fractional anisotropy (FA), and behavioral scores at 1 and 3 hours, 2, 7, and 14 days after traumatic brain injury (TBI) in rats. Open-skull TBI was induced over the left primary forelimb somatosensory cortex (N=8 and 3 sham). We found the abnormal areas of CBF and CR on days 0 and 2 were larger than those of the T2, ADC, and FA abnormalities. In the impact core, CBF was reduced on day 0, increased to 2.5 times of normal on day 2, and returned toward normal by day 14, whereas in the tissue surrounding the impact, hypoperfusion was observed on days 0 and 2. CR in the impact core was negative, most severe on day 2 but gradually returned toward normal. T2, ADC, and FA abnormalities in the impact core were detected on day 0, peaked on day 2, and pseudonormalized by day 14. Lesion volumes peaked on day 2 and were temporally correlated with forelimb asymmetry and foot-fault scores. This study quantified the effects of perturbed CBF and CR on structural magnetic resonance imaging and behavioral readouts.
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Affiliation(s)
- Justin A Long
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Lora T Watts
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA.,Departments of Cellular and Structure Biology, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Neurology, University of Texas Health Science Center, Houston, Texas, USA
| | - Wei Li
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Eric R Muir
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Robert C Boggs
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Abhinav Suri
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Neurology, University of Texas Health Science Center, Houston, Texas, USA.,Department of Opthalmology, University of Texas Health Science Center, San Antonio, Texas, USA.,South Texas Veterans Health Care System, San Antonio, Texas, USA
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38
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Cardenas DP, Muir ER, Huang S, Boley A, Lodge D, Duong TQ. Functional MRI during hyperbaric oxygen: Effects of oxygen on neurovascular coupling and BOLD fMRI signals. Neuroimage 2015; 119:382-9. [PMID: 26143203 DOI: 10.1016/j.neuroimage.2015.06.082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/12/2015] [Accepted: 06/27/2015] [Indexed: 11/28/2022] Open
Abstract
Hyperbaric oxygen (HBO) therapy is used to treat a number of ailments. Improved understanding of how HBO affects neuronal activity, cerebral blood flow (CBF) and blood-oxygenation-level dependent (BOLD) changes could shed light on the role of oxygen in neurovascular coupling and help guide HBO treatments. The goal of this study was to test two hypotheses: i) activation-induced CBF fMRI response is not dependent on hemoglobin deoxygenation, and ii) activation-induced BOLD fMRI is markedly attenuated under HBO. CBF and BOLD fMRI of forepaw stimulation in anesthetized rats under HBO at 3 atmospheres absolute (ATA) were compared with normobaric air. Robust BOLD and CBF fMRI were detected under HBO. Inflow effects and spin-density changes did not contribute significantly to the BOLD fMRI signal under HBO. Analysis of the T2(⁎)-weighted signal at normobaric air and 1, 2 and 3ATA oxygen in the tissue and the superior sagittal sinus showed a strong dependence on increasing inhaled [O2]. Spontaneous electrophysiological activity and evoked local-field potentials were reduced under HBO. The differences between normobaric air and HBO in basal and evoked electrical activity could not fully account for the strong BOLD responses under HBO. We concluded that activation-induced CBF regulation in the brain does not operate through an oxygen-sensing mechanism and that stimulus-evoked BOLD responses and the venous T2(⁎)-weighted signals still have room to increase under 3ATA HBO. To our knowledge, this is the first fMRI study under HBO, providing insights into the effects of HBO on neural activity, neurovascular coupling, tissue oxygenation, and the BOLD signal.
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Affiliation(s)
- Damon P Cardenas
- Graduate School of Biomedical Engineering, University of Texas at San Antonio, USA
| | - Eric R Muir
- Department of Ophthalmology, University of Texas Health Science Center, USA; Research Imaging Institute, University of Texas Health Science Center, USA
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center, USA
| | - Angela Boley
- Department of Pharmacology, University of Texas Health Science Center, USA
| | - Daniel Lodge
- Department of Pharmacology, University of Texas Health Science Center, USA
| | - Timothy Q Duong
- Graduate School of Biomedical Engineering, University of Texas at San Antonio, USA; Department of Ophthalmology, University of Texas Health Science Center, USA; Research Imaging Institute, University of Texas Health Science Center, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, TX, USA.
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39
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Normobaric oxygen worsens outcome after a moderate traumatic brain injury. J Cereb Blood Flow Metab 2015; 35:1137-44. [PMID: 25690469 PMCID: PMC4640244 DOI: 10.1038/jcbfm.2015.18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/12/2015] [Accepted: 01/16/2015] [Indexed: 11/08/2022]
Abstract
Traumatic brain injury (TBI) is a multifaceted injury and a leading cause of death in children, young adults, and increasingly in Veterans. However, there are no neuroprotective agents clinically available to counteract damage or promote repair after brain trauma. This study investigated the neuroprotective effects of normobaric oxygen (NBO) after a controlled cortical impact in rats. The central hypothesis was that NBO treatment would reduce lesion volume and functional deficits compared with air-treated animals after TBI by increasing brain oxygenation thereby minimizing ischemic injury. In a randomized double-blinded design, animals received either NBO (n = 8) or normal air (n = 8) after TBI. Magnetic resonance imaging (MRI) was performed 0 to 3 hours, and 1, 2, 7, and 14 days after an impact to the primary forelimb somatosensory cortex. Behavioral assessments were performed before injury induction and before MRI scans on days 2, 7, and 14. Nissl staining was performed on day 14 to corroborate the lesion volume detected from MRI. Contrary to our hypothesis, we found that NBO treatment increased lesion volume in a rat model of moderate TBI and had no positive effect on behavioral measures. Our results do not promote the acute use of NBO in patients with moderate TBI.
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40
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Jiang Z, Watts LT, Huang S, Shen Q, Rodriguez P, Chen C, Zhou C, Duong TQ. The Effects of Methylene Blue on Autophagy and Apoptosis in MRI-Defined Normal Tissue, Ischemic Penumbra and Ischemic Core. PLoS One 2015; 10:e0131929. [PMID: 26121129 PMCID: PMC4488003 DOI: 10.1371/journal.pone.0131929] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 06/09/2015] [Indexed: 12/11/2022] Open
Abstract
Methylene blue (MB) USP, which has energy-enhancing and antioxidant properties, is currently used to treat methemoglobinemia and cyanide poisoning in humans. We recently showed that MB administration reduces infarct volume and behavioral deficits in rat models of ischemic stroke and traumatic brain injury. This study reports the underlying molecular mechanisms of MB neuroprotection following transient ischemic stroke in rats. Rats were subjected to transient (60-mins) ischemic stroke. Multimodal MRI during the acute phase and at 24 hrs were used to define three regions of interest (ROIs): i) the perfusion-diffusion mismatch salvaged by reperfusion, ii) the perfusion-diffusion mismatch not salvaged by reperfusion, and iii) the ischemic core. The tissues from these ROIs were extracted for western blot analyses of autophagic and apoptotic markers. The major findings were: 1) MB treatment reduced infarct volume and behavioral deficits, 2) MB improved cerebral blood flow to the perfusion-diffusion mismatch tissue after reperfusion and minimized harmful hyperperfusion 24 hrs after stroke, 3) MB inhibited apoptosis and enhanced autophagy in the perfusion-diffusion mismatch, 4) MB inhibited apoptotic signaling cascades (p53-Bax-Bcl2-Caspase3), and 5) MB enhanced autophagic signaling cascades (p53-AMPK-TSC2-mTOR). MB induced neuroprotection, at least in part, by enhancing autophagy and reducing apoptosis in the perfusion-diffusion mismatch tissue following ischemic stroke.
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Affiliation(s)
- Zhao Jiang
- Department of Anatomy and Embryology, Peking University Health Science Center, Beijing, China
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Lora Talley Watts
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Pavel Rodriguez
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Chunhua Chen
- Department of Anatomy and Embryology, Peking University Health Science Center, Beijing, China
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Changman Zhou
- Department of Anatomy and Embryology, Peking University Health Science Center, Beijing, China
| | - Timothy Q. Duong
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
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41
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Talley Watts L, Shen Q, Deng S, Chemello J, Duong TQ. Manganese-Enhanced Magnetic Resonance Imaging of Traumatic Brain Injury. J Neurotrauma 2015; 32:1001-10. [PMID: 25531419 DOI: 10.1089/neu.2014.3737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Calcium dysfunction is involved in secondary traumatic brain injury (TBI). Manganese-enhanced MRI (MEMRI), in which the manganese ion acts as a calcium analog and a MRI contrast agent, was used to study rats subjected to a controlled cortical impact. Comparisons were made with conventional T2 MRI, sensorimotor behavior, and immunohistology. The major findings were: (1) Low-dose manganese (29 mg/kg) yielded excellent contrast with no negative effects on behavior scores relative to vehicle; (2) T1-weighted MEMRI was hyperintense in the impact area at 1-3 h, hypointense on day 2, and markedly hypointense with a hyperintense area surrounding the core on days 7 and/or 14, in contrast to the vehicle group, which did not show a biphasic profile; (3) in the hyperacute phase, the area of hyperintense T1-weighted MEMRI was larger than that of T2 MRI; (4) glial fibrillary acidic protein staining revealed that the MEMRI signal void in the impact core and the hyperintense area surrounding the core on day 7 and/or 14 corresponded to tissue cavitation and reactive gliosis, respectively; (5) T2 MRI showed little contrast in the impact core at 2 h, hyperintense on day 2 (indicative of vasogenic edema), hyperintense in some animals but pseudonormalized in others on day 7 and/or 14; (6) behavioral deficit peaked on day 2. We concluded that MEMRI detected early excitotoxic injury in the hyperacute phase, preceding vasogenic edema. In the subacute phase, MEMRI detected contrast consistent with tissue cavitation and reactive gliosis. MEMRI offers novel contrasts of biological processes that complement conventional MRI in TBI.
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Affiliation(s)
- Lora Talley Watts
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas.,2 Department of Cellular and Structure Biology, University of Texas Health Science Center , San Antonio, Texas.,3 Department of Neurology, University of Texas Health Science Center , San Antonio, Texas
| | - Qiang Shen
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas.,4 Department of Ophthalmology, University of Texas Health Science Center , San Antonio, Texas
| | - Shengwen Deng
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas
| | - Jonathan Chemello
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas
| | - Timothy Q Duong
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas.,4 Department of Ophthalmology, University of Texas Health Science Center , San Antonio, Texas.,5 South Texas Veterans Health Care System , San Antonio, Texas
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42
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Cerebral angiography, blood flow and vascular reactivity in progressive hypertension. Neuroimage 2015; 111:329-37. [PMID: 25731987 DOI: 10.1016/j.neuroimage.2015.02.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/18/2015] [Accepted: 02/22/2015] [Indexed: 11/23/2022] Open
Abstract
Chronic hypertension alters cerebral vascular morphology, cerebral blood flow (CBF), cerebrovascular reactivity, and increses susceptibility to neurological disorders. This study evaluated: i) the lumen diameters of major cerebral and downstream arteries using magnetic resonance angiography, ii) basal CBF, and iii) cerebrovascular reactivity to hypercapnia of multiple brain regions using arterial-spin-labeling technique in spontaneously hypertensive rats (SHR) at different stages. Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR, lumen diameter started to reduce, basal CBF, and hypercapnic CBF response were higher from elevated arterial blood pressure, but there was no evidence of stenosis, compared to age-matched WKY. In 20-week SHR, lumen diameter remained reduced, CBF returned toward normal from vasoconstriction, hypercapnic CBF response reversed and became smaller, but without apparent stenosis. In 40-week SHR, lumen diameter remained reduced and basal CBF further decreased, resulting in larger differences compared to WKY. There was significant stenosis in main supplying cerebral vessels. Hypercapnic CBF response further decreased, with some animals showing negative hypercapnic CBF responses in some brain regions, indicative of compromised cerebrovascular reserve. The territory with negative hypercapnia CBF responses corresponded with the severity of stenosis in arteries that supplied those territories. We also found enlargement of downstream vessels and formation of collateral vessels as compensatory responses to stenosis of upstream vessels. The middle cerebral and azygos arteries were amongst the most susceptible to hypertension-induced changes. Multimodal MRI provides clinically relevant data that might be useful to characterize disease pathogenesis, stage disease progression, and monitor treatment effects in hypertension.
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43
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Long JA, Watts LT, Chemello J, Huang S, Shen Q, Duong TQ. Multiparametric and longitudinal MRI characterization of mild traumatic brain injury in rats. J Neurotrauma 2015; 32:598-607. [PMID: 25203249 DOI: 10.1089/neu.2014.3563] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
This study reports T2 and diffusion-tensor magnetic resonance imaging (MRI) studies of a mild open-skull, controlled cortical impact injury in rats (n=6) from 3 h to up to 14 d after traumatic brain injury (TBI). Comparison was made with longitudinal behavioral measurements and end-point histology. The impact was applied over the left primary forelimb somatosensory cortex (S1FL). The major findings were: 1) In the S1FL, T2 increased and fractional anisotropy (FA) decreased at 3 h after TBI and gradually returned toward normal by Day 14; 2) in the S1FL, the apparent diffusion coefficient (ADC) increased at 3 h, peaked on Day 2, and gradually returned toward normal at Day 14; 3) in the corpus callosum underneath the S1FL, FA decreased at 3 h to Day 2 but returned to normal at Day 7 and 14, whereas T2 and ADC were normal throughout; 4) heterogeneous hyperintense and hypointense T2 map intensities likely indicated the presence of hemorrhage but were not independently verified; 5) lesion volumes defined by abnormal T2, ADC, and FA showed similar temporal patterns, peaking around Day 2 and returning toward normal on Day 14; 6) the temporal profiles of lesion volumes were consistent with behavioral scores assessed by forelimb placement and forelimb foot fault tests; and 7) at 14 d post-TBI, there was substantial tissue recovery by MRI, which could either reflect true tissue recovery or reabsorption of edema. Histology performed 14 d post-TBI, however, showed a small cavitation and significant neuronal degeneration surrounding the cavitation in S1FL. Thus, the observed improvement of behavioral scores likely involves both functional recovery and functional compensation.
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Affiliation(s)
- Justin Alexander Long
- 1 Research Imaging Institute, University of Texas Health Science Center at San Antonio , San Antonio, Texas
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44
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Shen Q, Huang S, Duong TQ. Ultra-high spatial resolution basal and evoked cerebral blood flow MRI of the rat brain. Brain Res 2014; 1599:126-36. [PMID: 25557404 DOI: 10.1016/j.brainres.2014.12.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/19/2014] [Accepted: 12/23/2014] [Indexed: 11/18/2022]
Abstract
Cerebral blood flow (CBF) is tightly coupled to metabolism and neural activity under normal physiological conditions, and is often perturbed in disease states. The goals of this study were to implement a high-resolution (up to 50×38μm(2)) CBF MRI protocol of the rat brain, create a digital CBF atlas, report CBF values for 30+ brain structures based on the atlas, and explore applications of high-resolution CBF fMRI of forepaw stimulation. Excellent blood-flow contrasts were observed among different cortical and subcortical structures. CBF MRI showed column-like alternating bright and dark bands in the neocortices, reflecting the layout of descending arterioles and ascending venules, respectively. CBF MRI also showed lamina-like alternating bright and dark layers across the cortical thicknesses, consistent with the underlying vascular density. CBF profiles across the cortical thickness showed two peaks in layers IV and VI and a shallow trough in layer V. Whole-brain CBF was about 0.89ml/g/min, with the highest CBF values found amongst the neocortical structures (1ml/g/min, range: 0.89-1.16ml/g/min) and the lowest CBF values in the corpus callosum (0.32ml/g/min), yielding a gray:white matter CBF ratio of 3.1. CBF fMRI responses peaked across layers IV-V, whereas the BOLD fMRI responses showed a peak in the superficial layers II-III. High-resolution basal CBF MRI, evoked CBF fMRI, and CBF brain atlas can be used to study neurological disorders (such as ischemic stroke).
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Affiliation(s)
- Qiang Shen
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, 8403 Floyd Curl Dr, TX 78229, United States; Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, 8403 Floyd Curl Dr, TX 78229, United States
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, 8403 Floyd Curl Dr, TX 78229, United States; Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, United States; Department of Radiology, University of Texas Health Science Center, San Antonio, TX, United States; Department of Physiology, University of Texas Health Science Center, San Antonio, TX, United States; South Texas Veterans Health Care System, San Antonio, TX, United States.
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45
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Dynamic perfusion and diffusion MRI of cortical spreading depolarization in photothrombotic ischemia. Neurobiol Dis 2014; 71:131-9. [PMID: 25066776 DOI: 10.1016/j.nbd.2014.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/15/2014] [Accepted: 07/16/2014] [Indexed: 11/21/2022] Open
Abstract
Cortical spreading depolarization (CSD) is known to exacerbate ischemic damage, as the number of CSDs correlates with the final infarct volumes and suppressing CSDs improves functional outcomes. To investigate the role of CSD in ischemic damage, we developed a novel rat model of photothrombotic ischemia using a miniature implantable optic fiber that allows lesion induction inside the magnetic resonance imaging (MRI) scanner. We were able to precisely control the location and the size of the ischemic lesion, and continuously monitor dynamic perfusion and diffusion MRI signal changes at high temporal resolution before, during and after the onset of focal ischemia. Our model showed that apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) in the ischemic core dropped immediately after lesion onset by 20±6 and 41±23%, respectively, and continually declined over the next 5h. Meanwhile, CSDs were observed in all animals (n=36) and displayed either a transient decrease of ADC by 17±3% or an increase of CBF by 104±15%. All CSDs were initiated from the rim of the ischemic core, propagated outward, and confined to the ipsilesional cortex. Additionally, we demonstrated that by controlling the size of perfusion-diffusion mismatch (which approximates the penumbra) in our model, the number of CSDs correlated with the mismatch area rather than the final infarct volume. This study introduces a novel platform to study CSDs in real-time with high reproducibility using MRI.
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46
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Kauppinen RA. Multiparametric magnetic resonance imaging of acute experimental brain ischaemia. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 80:12-25. [PMID: 24924265 DOI: 10.1016/j.pnmrs.2014.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/07/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
Ischaemia is a condition in which blood flow either drops to zero or proceeds at severely decreased levels that cannot supply sufficient oxidizable substrates to maintain energy metabolism in vivo. Brain, a highly oxidative organ, is particularly susceptible to ischaemia. Ischaemia leads to loss of consciousness in seconds and, if prolonged, permanent tissue damage is inevitable. Ischaemia primarily results in a collapse of cerebral energy state, followed by a series of subtle changes in anaerobic metabolism, ion and water homeostasis that eventually initiate destructive internal and external processes in brain tissue. (31)P and (1)H NMR spectroscopy were initially used to evaluate anaerobic metabolism in brain. However, since the early 1990s (1)H Magnetic Resonance Imaging (MRI), exploiting the nuclear magnetism of tissue water, has become the key method for assessment of ischaemic brain tissue. This article summarises multi-parametric (1)H MRI work that has exploited diffusion, relaxation and magnetisation transfer as 'contrasts' to image ischaemic brain in preclinical models for the first few hours, with a view to assessing evolution of ischaemia and tissue viability in a non-invasive manner.
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Affiliation(s)
- Risto A Kauppinen
- School of Experimental Psychology and Clinical Research and Imaging Centre, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK.
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47
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Zhang X, Tong F, Li CX, Yan Y, Nair G, Nagaoka T, Tanaka Y, Zola S, Howell L. A fast multiparameter MRI approach for acute stroke assessment on a 3T clinical scanner: preliminary results in a non-human primate model with transient ischemic occlusion. Quant Imaging Med Surg 2014; 4:112-22. [PMID: 24834423 DOI: 10.3978/j.issn.2223-4292.2014.04.06] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/21/2014] [Indexed: 11/14/2022]
Abstract
Many MRI parameters have been explored and demonstrated the capability or potential to evaluate acute stroke injury, providing anatomical, microstructural, functional, or neurochemical information for diagnostic purposes and therapeutic development. However, the application of multiparameter MRI approach is hindered in clinic due to the very limited time window after stroke insult. Parallel imaging technique can accelerate MRI data acquisition dramatically and has been incorporated in modern clinical scanners and increasingly applied for various diagnostic purposes. In the present study, a fast multiparameter MRI approach including structural T1-weighted imaging (T1W), T2-weighted imaging (T2W), diffusion tensor imaging (DTI), T2-mapping, proton magnetic resonance spectroscopy, cerebral blood flow (CBF), and magnetization transfer (MT) imaging, was implemented and optimized for assessing acute stroke injury on a 3T clinical scanner. A macaque model of transient ischemic stroke induced by a minimal interventional approach was utilized for evaluating the multiparameter MRI approach. The preliminary results indicate the surgical procedure successfully induced ischemic occlusion in the cortex and/or subcortex in adult macaque monkeys (n=4). Application of parallel imaging technique substantially reduced the scanning duration of most MRI data acquisitions, allowing for fast and repeated evaluation of acute stroke injury. Hence, the use of the multiparameter MRI approach with up to five quantitative measures can provide significant advantages in preclinical or clinical studies of stroke disease.
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Affiliation(s)
- Xiaodong Zhang
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Frank Tong
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Chun-Xia Li
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Yumei Yan
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Govind Nair
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Tsukasa Nagaoka
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Yoji Tanaka
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Stuart Zola
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Leonard Howell
- 1 Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA ; 2 Department of Radiology, School of Medicine, Emory University, Atlanta, GA 30322, USA ; 3 the Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA 30322, USA ; 4 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA ; 5 Sony Corporation, Tokyo, Japan ; 6 Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan ; 7 Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA 30322, USA
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Talley Watts L, Long JA, Chemello J, Van Koughnet S, Fernandez A, Huang S, Shen Q, Duong TQ. Methylene blue is neuroprotective against mild traumatic brain injury. J Neurotrauma 2014; 31:1063-71. [PMID: 24479842 DOI: 10.1089/neu.2013.3193] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Methylene blue (MB) has known energy-enhancing and antioxidant properties. This study tested the hypothesis that MB treatment reduces lesion volume and behavioral deficits in a rat model of mild TBI. In a randomized double-blinded design, animals received either MB (n=5) or vehicle (n=6) after TBI. Studies were performed on 0, 1, 2, 7, and 14 days following an impact to the primary forelimb somatosensory cortex. MRI lesion was not apparent 1 h after TBI, became apparent 3 h after TBI, and peaked at 2 days for both groups. The MB-treated animals showed significantly smaller MRI lesion volume than the vehicle-treated animals at all time points studied. The MB-treated animals exhibited significantly improved scores on forelimb placement asymmetry and foot fault tests than did the vehicle-treated animals at all time points studied. Smaller numbers of dark-stained Nissl cells and Fluoro-Jade(®) positive cells were observed in the MB-treated group than in vehicle-treated animals 14 days post-TBI. In conclusion, MB treatment minimized lesion volume, behavioral deficits, and neuronal degeneration following mild TBI. MB is already approved by the United States Food and Drug Administration (FDA) to treat a number of indications, likely expediting future clinical trials in TBI.
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Affiliation(s)
- Lora Talley Watts
- 1 Research Imaging Institute, University of Texas Health Science Center , San Antonio, Texas
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49
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Shen Q, Du F, Huang S, Duong TQ. Effects of cerebral ischemic and reperfusion on T2*-weighted MRI responses to brief oxygen challenge. J Cereb Blood Flow Metab 2014; 34:169-75. [PMID: 24129750 PMCID: PMC3887355 DOI: 10.1038/jcbfm.2013.179] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 08/19/2013] [Accepted: 09/19/2013] [Indexed: 11/09/2022]
Abstract
This study characterized the effects of cerebral ischemia and reperfusion on T2*-weighted magnetic resonance image (MRI) responses to brief oxygen challenge (OC) in transient (60 minutes) cerebral ischemia in rats. During occlusion, the ischemic core tissue showed no significant OC response, whereas the perfusion-diffusion mismatch tissue showed markedly higher percent changes relative to normal tissue. After reperfusion, much of the pixels with initial exaggerated OC responses showed normal OC responses, and the majority of these tissues were salvaged as defined by endpoint T2 MRI. The initial core pixels showed exaggerated OC responses after reperfusion, but the majority of the core pixels eventually became infarct, suggesting exaggerated OC responses do not necessarily reflect salvageable tissue. Twenty-four hours after stroke, basal T1 increased in the ischemic core. Oxygen challenge decreased T1 significantly in the core, indicative of the substantial increases in dissolved oxygen in the core as the result of hyperperfusion. We concluded that exaggerated T2*-weighted MRI responses to OC offer useful insight in ischemic tissue fates. However, exaggerated OC pixels are not all salvageable, and they exhibited complex dynamics depending on reperfusion status, hyperperfusion, and edema effects.
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Affiliation(s)
- Qiang Shen
- 1] Department of Research Imaging Institute, San Antonio, Texas, USA [2] Department of Ophthalmology, San Antonio, Texas, USA [3] Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Fang Du
- Department of Research Imaging Institute, San Antonio, Texas, USA
| | - Shiliang Huang
- Department of Research Imaging Institute, San Antonio, Texas, USA
| | - Timothy Q Duong
- 1] Department of Research Imaging Institute, San Antonio, Texas, USA [2] Department of Ophthalmology, San Antonio, Texas, USA [3] Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA [4] South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, Texas, USA
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50
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Muir ER, Watts LT, Tiwari YV, Bresnen A, Shen Q, Duong TQ. Quantitative cerebral blood flow measurements using MRI. Methods Mol Biol 2014; 1135:205-11. [PMID: 24510866 DOI: 10.1007/978-1-4939-0320-7_17] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Magnetic resonance imaging can be utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.
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Affiliation(s)
- Eric R Muir
- Department of Ophthalmology, Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
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