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Ng FC, Churilov L, Yassi N, Kleinig TJ, Thijs V, Wu TY, Shah DG, Dewey HM, Sharma G, Desmond PM, Yan B, Parsons MW, Donnan GA, Davis SM, Mitchell PJ, Leigh R, Campbell BCV. Reduced Severity of Tissue Injury Within the Infarct May Partially Mediate the Benefit of Reperfusion in Ischemic Stroke. Stroke 2022; 53:1915-1923. [PMID: 35135319 DOI: 10.1161/strokeaha.121.036670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Emerging data suggest tissue within the infarct lesion is not homogenously damaged following ischemic stroke but has a gradient of injury. Using blood-brain-barrier (BBB) disruption as a marker of tissue injury, we tested whether therapeutic reperfusion improves clinical outcome by reducing the severity of tissue injury within the infarct in patients with ischemic stroke. METHODS In a pooled analysis of patients treated for anterior circulation large vessel occlusion in the EXTEND-IA TNK (Tenecteplase Versus Alteplase Before Endovascular Therapy for Ischemic Stroke) and EXTEND-IA part-2 (Determining the Optimal Dose of Tenecteplase Before Endovascular Therapy for Ischaemic Stroke) trials, post-treatment BBB permeability at 24 hours was calculated based on the extent of T1-brightening by extravascular gadolinium on T2* perfusion-weighted imaging and measured within the diffusion-weighted-imaging lesion. First, to determine the clinical significance of BBB disruption as a marker of severity of tissue injury, we examined the association between post-treatment BBB permeability and functional outcome. Second, we performed an exploratory (reperfusion, BBB permeability, functional outcome) mediation analysis to estimate the proportion of the reperfusion-outcome relationship that is mediated by change in BBB permeability. RESULTS In the 238 patients analyzed, an increased BBB permeability measured within the infarct at 24 hours was associated with a reduced likelihood of favorable outcome (90-day modified Rankin Scale score of ≤2) after adjusting for age, baseline National Institutes of Health Stroke Scale, premorbid modified Rankin Scale, infarct topography, laterality, thrombolytic agent, sex, parenchymal hematoma, and follow-up infarct volume (adjusted odds ratio, 0.86 [95% CI, 0.75-0.98], P=0.023). Mediation analysis suggested reducing the severity of tissue injury (as estimated by BBB permeability) accounts for 18.2% of the association between reperfusion and favorable outcome, as indicated by a reduction in the regression coefficient of reperfusion after addition of BBB permeability as a covariate. CONCLUSIONS In patients with ischemic stroke, reduced severity of tissue injury within the infarct, as determined by assessing the integrity of the BBB, is independently associated with improved functional outcome. In addition to reducing diffusion-weighted imaging-defined infarct volume, reperfusion may also improve clinical outcome by reducing tissue injury severity within the infarct.
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Affiliation(s)
- Felix C Ng
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.).,Department of Neurology, Austin Hospital, Austin Health, Heidelberg, Australia (F.C.N., V.T.)
| | - Leonid Churilov
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.).,The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia. (L.C., V.T., B.C.V.C.).,Melbourne Medical School, The University of Melbourne, Heidelberg, Victoria, Australia (L.C.)
| | - Nawaf Yassi
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.).,Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia (N.Y.)
| | - Timothy J Kleinig
- Department of Neurology, Royal Adelaide Hospital, Australia (T.J.K.)
| | - Vincent Thijs
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia. (L.C., V.T., B.C.V.C.).,Department of Neurology, Austin Hospital, Austin Health, Heidelberg, Australia (F.C.N., V.T.)
| | - Teddy Y Wu
- Department of Neurology, Christchurch Hospital, New Zealand (T.Y.W.)
| | - Darshan G Shah
- Department of Neurology, Princess Alexandra Hospital, Brisbane, Australia (D.G.S.)
| | - Helen M Dewey
- Eastern Health and Eastern Health Clinical School, Department of Neurosciences, Monash University, Clayton, Australia (H.M.D.)
| | - Gagan Sharma
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.)
| | - Patricia M Desmond
- Department of Radiology, Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (P.M.D., B.Y., P.J.M.)
| | - Bernard Yan
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.).,Department of Radiology, Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (P.M.D., B.Y., P.J.M.)
| | - Mark W Parsons
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.)
| | - Geoffrey A Donnan
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.)
| | - Stephen M Davis
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.)
| | - Peter J Mitchell
- Department of Radiology, Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (P.M.D., B.Y., P.J.M.)
| | - Richard Leigh
- Department of Neurology, John Hopkins University, Baltimore, MD (R.L.)
| | - Bruce C V Campbell
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Parkville, Australia. (F.C.N., L.C., N.Y., G.S., B.Y., M.W.P., G.A.S., S.M.D., B.C.V.C.).,The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia. (L.C., V.T., B.C.V.C.)
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Baudu J, Gerbaud E, Catargi B, Montaudon M, Beauvieux MC, Sagnier S, Debruxelles S, Renou P, Poli M, Olindo S, Couture M, Marnat G, Sibon I. High glycemic variability: An underestimated determinant of stroke functional outcome following large vessel occlusion. Rev Neurol (Paris) 2022; 178:732-740. [DOI: 10.1016/j.neurol.2021.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 12/19/2022]
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3
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Obenaus A, Badaut J. Role of the noninvasive imaging techniques in monitoring and understanding the evolution of brain edema. J Neurosci Res 2021; 100:1191-1200. [PMID: 34048088 DOI: 10.1002/jnr.24837] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 03/13/2021] [Indexed: 12/21/2022]
Abstract
Human brain injury elicits accumulation of water within the brain due to a variety of pathophysiological processes. As our understanding of edema emerged two temporally (and cellular) distinct processes were identified, cytotoxic and vasogenic edema. The emergence of both types of edema is reflected by the temporal evolution and is influenced by the underlying pathology (type and extent). However, this two-edema compartment model does not adequately describe the transition between cytotoxic and vasogenic edema. Hence, a third category has been proposed, termed ionic edema, that is observed in the transition between cytotoxic and vasogenic edema. Magnetic resonance neuroimaging of edema today primarily utilizes T2-weighted (T2WI) and diffusion-weighted imaging (DWI). Clinical diagnostics and translational science studies have clearly demonstrated the temporal ability of both T2WI and DWI to monitor edema content and evolution. DWI measures water mobility within the brain reflecting cytotoxic edema. T2WI at later time points when vasogenic edema develops visualizes increased water content in the brain. Clinically relevant imaging modalities, including ultrasound and positron emission tomography, are not typically used to assess edema. In sum, edema imaging is an important cornerstone of clinical diagnostics and translational studies and can guide effective therapeutics manage edema and improve patient outcomes.
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Affiliation(s)
- Andre Obenaus
- Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.,Department of Pediatrics, University of California, Irvine, Irvine, CA, USA
| | - Jérôme Badaut
- Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.,CNRS UMR5287, INCIA, University of Bordeaux, Bordeaux, France
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4
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Kosior-Jarecka E, Pankowska A, Polit P, Stępniewski A, Symms MR, Kozioł P, Żarnowski T, Pietura R. Volume of Lateral Geniculate Nucleus in Patients with Glaucoma in 7Tesla MRI. J Clin Med 2020; 9:jcm9082382. [PMID: 32722571 PMCID: PMC7466157 DOI: 10.3390/jcm9082382] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 12/19/2022] Open
Abstract
The aim of the study was to assess the volume of the lateral geniculate nucleus (LGN) in patients with open-angle glaucoma in 7Tesla MRI and to evaluate its relation to RNFL thickness and VF indices. Material and methods. The studied group consisted of 20 open-angle glaucoma patients with bilaterally the same stage of glaucoma (11 with early glaucoma and nine with advanced glaucoma) and nine healthy volunteers from the Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Poland. Circumpapillary RNFL-thickness measurements were performed using OCT in all patients and visual fields were performed in the glaucoma group. A 7Tesla MRI was performed to assess the volume of both lateral geniculate bodies. Results. The LGN volume varied significantly between groups from 122.1 ± 14.4 mm3 (right LGN) and 101.6 ± 13.3 mm3 (left LGN) in the control group to 80.2 ± 17.7 mm3 (right LGN) and 71.8 ± 14.2 mm3 (left LGN) in the advanced glaucoma group (right LGN p = 0.003, left LGN p = 0.018). However, volume values from early glaucoma: right LGN = 120.2 ± 26.5 mm3 and left LGN = 103.2 ± 28.0 mm3 differed significantly only from values from the advanced group (right LGN p = 0.006, left LGN p = 0.012), but not from controls (right LGN p = 0.998, left LGN p = 0.986). There were no significant correlations between visual field indices (MD (mean deviation) and VFI (visual field index)) and LGN volumes in both glaucoma groups. Significant correlations between mean RNFL (retinal nerve fiber layers) thickness and corresponding and contralateral LGN were observed for the control group (corresponding LGN: p = 0.064; contralateral LGN: p = 0.031) and early glaucoma (corresponding LGN: p = 0.017; contralateral LGN: p = 0.008), but not advanced glaucoma (corresponding LGN: p = 0.496; contralateral LGN: p = 0.258). Conclusions. The LGN volume decreases in the course of glaucoma. These changes are correlated with RNFL thickness in early stages of glaucoma and are not correlated with visual field indices.
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Affiliation(s)
- Ewa Kosior-Jarecka
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, 20-079 Lublin, Poland; (P.P.); (T.Ż.)
- Correspondence:
| | - Anna Pankowska
- Department of Radiography, Medical University of Lublin, 20-079 Lublin, Poland; (A.P.); (P.K.); (R.P.)
| | - Piotr Polit
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, 20-079 Lublin, Poland; (P.P.); (T.Ż.)
| | - Andrzej Stępniewski
- Centrum ECO-TECH COMPLEX Maria Curie-Skłodowska University in Lublin, 20-612 Lublin, Poland;
| | | | - Paulina Kozioł
- Department of Radiography, Medical University of Lublin, 20-079 Lublin, Poland; (A.P.); (P.K.); (R.P.)
| | - Tomasz Żarnowski
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, 20-079 Lublin, Poland; (P.P.); (T.Ż.)
| | - Radosław Pietura
- Department of Radiography, Medical University of Lublin, 20-079 Lublin, Poland; (A.P.); (P.K.); (R.P.)
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5
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Sagnier S, Sibon I. The new insights into human brain imaging after stroke. J Neurosci Res 2019; 100:1171-1181. [PMID: 31498491 DOI: 10.1002/jnr.24525] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 08/22/2019] [Accepted: 08/28/2019] [Indexed: 12/16/2022]
Abstract
Over the last two decades, developments of human brain stroke imaging have raised several questions about the place of new MRI biomarkers in the acute management of stroke and the prediction of poststroke outcome. Recent studies have demonstrated the main role of perfusion-weighted imaging in the identification of the best cerebral perfusion profile for a better response after reperfusion therapies in acute ischemic stroke. A major issue remains the early prediction of stroke outcome. While voxel-based lesion-symptom mapping emphasized the influence of stroke location, the analysis of the brain parenchyma underpinning the stroke lesion showed the relevance of prestroke cerebral status, including cortical atrophy, white matter integrity, or presence of chronic cortical cerebral microinfarcts. Moreover, besides the evaluation of the visually abnormal brain tissue, the analysis of normal-appearing brain parenchyma using diffusion tensor imaging and magnetization transfer imaging or spectroscopy offered new biomarkers to improve the prediction of the prognosis and new targets to follow in therapeutic trials. The aim of this review was to depict the main new radiological biomarkers reported in the last two decades that will provide a more thorough prediction of functional, motor, and neuropsychological outcome following the stroke. These new developments in neuroimaging might be a cornerstone in the emerging personalized medicine for stroke patients.
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Affiliation(s)
- Sharmila Sagnier
- UMR-5287 CNRS, Université de Bordeaux, EPHE PSL Research University, Bordeaux, France.,CHU de Bordeaux, Unité Neuro-vasculaire, Bordeaux, France
| | - Igor Sibon
- UMR-5287 CNRS, Université de Bordeaux, EPHE PSL Research University, Bordeaux, France.,CHU de Bordeaux, Unité Neuro-vasculaire, Bordeaux, France
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6
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Li C, Lan C, Zhang X, Yin L, Hao X, Tian J, Lin L, Sun H, Yao Z, Feng X, Jia J, Yang Y. Evaluation of Diffusional Kurtosis Imaging in Sub-acute Ischemic Stroke: Comparison with Rehabilitation Treatment Effect. Cell Transplant 2019; 28:1053-1061. [PMID: 30907127 PMCID: PMC6728709 DOI: 10.1177/0963689719837919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Stroke is a serious worldwide medical condition that causes neurological function disability. Diffusional kurtosis imaging, which measures the non-Gaussianity of water diffusion, has been demonstrated to be a sensitive biomarker in many neuro-pathologies. This study explores the relationship between neural function recovery and transformation of the ischemic lesion and/or corticospinal tract during the sub-acute phase after stroke by using diffusional kurtosis imaging. We performed a prospective study of function recovery and K metrics of 43 patients with sub-acute ischemic stroke in the middle cerebral artery territory. The effect of rehabilitation treatment was evaluated using both the Fugl-Meyer motor function score and modified Barthel index score at post-treatment compared with admission, and patients were allocated to two groups: good and poor rehabilitation effect (GRE and PRE). Metrics of diffusional kurtosis imaging within ischemic lesion and along the corticospinal tract were acquired, respectively. All three relative axial diffusional kurtoses (rKas) along the corticospinal tract in the GRE group ( n = 21) were significantly larger than those of the PRE group ( n = 22), including rKa in the posterior limb of internal capsule, rKa in the cerebral peduncle, and rKa in the basal part of the pons ( p = 0.014, 0.005, and 0.021, respectively). This multi-parametric magnetic resonance imaging study showed that diffusional kurtosis imaging has the potential to complement existing stroke imaging techniques and revealed its own advantages in elucidating the possible biophysical mechanism of functional restoration underlying ischemic stroke.
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Affiliation(s)
- C. Li
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - C. Lan
- Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, China
- Department of Rehabilitation, Shanxi Dayi Hospital, Taiyuan, China
| | - X. Zhang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- Department of Radiotherapy, Shanghai Eastern Hepatobiliary Surgery Hospital, Shanghai, China
| | - L. Yin
- Department of Radiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, China
| | - X. Hao
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - J. Tian
- Department of Radiology, Renji Hospital, Shanghai Jiao Tong University, China
| | - L. Lin
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - H. Sun
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Z. Yao
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - X. Feng
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - J. Jia
- Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, China
- Both the authors contributed equally to this article
| | - Y. Yang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- Both the authors contributed equally to this article
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7
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Khodanovich MY, Kisel AA, Akulov AE, Atochin DN, Kudabaeva MS, Glazacheva VY, Svetlik MV, Medvednikova YA, Mustafina LR, Yarnykh VL. Quantitative assessment of demyelination in ischemic stroke in vivo using macromolecular proton fraction mapping. J Cereb Blood Flow Metab 2018; 38:919-931. [PMID: 29372644 PMCID: PMC5987939 DOI: 10.1177/0271678x18755203] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A recent MRI method, fast macromolecular proton fraction (MPF) mapping, was used to quantify demyelination in the transient middle cerebral artery occlusion (MCAO) rat stroke model. MPF and other quantitative MRI parameters (T1, T2, proton density, and apparent diffusion coefficient) were compared with histological and immunohistochemical markers of demyelination (Luxol Fast Blue stain, (LFB)), neuronal loss (NeuN immunofluorescence), axonal loss (Bielschowsky stain), and inflammation (Iba1 immunofluorescence) in three animal groups ( n = 5 per group) on the 1st, 3rd, and 10th day after MCAO. MPF and LFB optical density (OD) were significantly reduced in the ischemic lesion on all days after MCAO relative to the symmetrical regions of the contralateral hemisphere. Percentage changes in MPF and LFB OD in the ischemic lesion relative to the contralateral hemisphere significantly differed on the first day only. Percentage changes in LFB OD and MPF were strongly correlated (R = 0.81, P < 0.001) and did not correlate with other MRI parameters. MPF also did not correlate with other histological variables. Addition of T2 into multivariate regression further improved agreement between MPF and LFB OD (R = 0.89, P < 0.001) due to correction of the edema effect. This study provides histological validation of MPF as an imaging biomarker of demyelination in ischemic stroke.
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Affiliation(s)
| | - Alena A Kisel
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation
| | - Andrey E Akulov
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation.,2 Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Dmitriy N Atochin
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation.,3 Cardiovascular Research Center, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA.,4 RASA Center in Tomsk, Tomsk Polytechnic University, Tomsk, Russian Federation
| | - Marina S Kudabaeva
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation
| | | | - Michael V Svetlik
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation
| | - Yana A Medvednikova
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation
| | - Lilia R Mustafina
- 5 Department of Histology, Embryology and Cytology, Siberian State Medical University, Tomsk, Russian Federation
| | - Vasily L Yarnykh
- 1 Laboratory of Neurobiology, Tomsk State University, Tomsk, Russian Federation.,6 Department of Radiology, University of Washington, Seattle, WA, USA
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8
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Imaging the Transformation of Ipsilateral Internal Capsule Following Focal Cerebral Ischemia in Rat by Diffusion Kurtosis Imaging. J Stroke Cerebrovasc Dis 2017; 26:42-48. [DOI: 10.1016/j.jstrokecerebrovasdis.2016.08.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/05/2016] [Accepted: 08/17/2016] [Indexed: 12/13/2022] Open
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9
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Tummala S, Roy B, Park B, Kang DW, Woo MA, Harper RM, Kumar R. Associations between brain white matter integrity and disease severity in obstructive sleep apnea. J Neurosci Res 2016; 94:915-923. [PMID: 27315771 PMCID: PMC4990476 DOI: 10.1002/jnr.23788] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/18/2016] [Accepted: 05/20/2016] [Indexed: 12/27/2022]
Abstract
Obstructive sleep apnea (OSA) is characterized by recurrent upper airway blockage, with continued diaphragmatic efforts to breathe during sleep. Brain structural changes in OSA appear in various regions, including white matter sites that mediate autonomic, mood, cognitive, and respiratory control. However, the relationships between brain white matter changes and disease severity in OSA are unclear. This study examines associations between an index of tissue integrity, magnetization transfer (MT) ratio values (which show MT between free and proton pools associated with tissue membranes and macromolecules), and disease severity (apnea-hypopnea index [AHI]) in OSA subjects. We collected whole-brain MT imaging data from 19 newly diagnosed, treatment-naïve OSA subjects (50.4 ± 8.6 years of age, 13 males, AHI 39.7 ± 24.3 events/hr], using a 3.0-Tesla MRI scanner. With these data, whole-brain MT ratio maps were calculated, normalized to common space, smoothed, and correlated with AHI scores by using partial correlation analyses (covariates, age and gender; P < 0.005). Multiple brain sites in OSA subjects, including superior and inferior frontal regions, ventral medial prefrontal cortex and nearby white matter, midfrontal white matter, insula, cingulate and cingulum bundle, internal and external capsules, caudate nuclei and putamen, basal forebrain, hypothalamus, corpus callosum, and temporal regions, showed principally lateralized negative correlations (P < 0.005). These regions showed significant correlations even with correction for multiple comparisons (cluster-level, family-wise error, P < 0.05), except for a few superior frontal areas. Predominantly negative correlations emerged between local MT values and OSA disease severity, indicating potential usefulness of MT imaging for examining the OSA condition. These findings indicate that OSA severity plays a significant role in white matter injury. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sudhakar Tummala
- Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Bhaswati Roy
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Bumhee Park
- Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Daniel W. Kang
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Mary A. Woo
- UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Ronald M. Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Brain Research Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Rajesh Kumar
- Department of Anesthesiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Brain Research Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Department of Radiological Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
- Department of Bioengineering, University of California at Los Angeles, Los Angeles, CA 90095, USA
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