51
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Donahue MJ, Achten E, Cogswell PM, De Leeuw FE, Derdeyn CP, Dijkhuizen RM, Fan AP, Ghaznawi R, Heit JJ, Ikram MA, Jezzard P, Jordan LC, Jouvent E, Knutsson L, Leigh R, Liebeskind DS, Lin W, Okell TW, Qureshi AI, Stagg CJ, van Osch MJP, van Zijl PCM, Watchmaker JM, Wintermark M, Wu O, Zaharchuk G, Zhou J, Hendrikse J. Consensus statement on current and emerging methods for the diagnosis and evaluation of cerebrovascular disease. J Cereb Blood Flow Metab 2018; 38:1391-1417. [PMID: 28816594 PMCID: PMC6125970 DOI: 10.1177/0271678x17721830] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/26/2017] [Accepted: 06/10/2017] [Indexed: 01/04/2023]
Abstract
Cerebrovascular disease (CVD) remains a leading cause of death and the leading cause of adult disability in most developed countries. This work summarizes state-of-the-art, and possible future, diagnostic and evaluation approaches in multiple stages of CVD, including (i) visualization of sub-clinical disease processes, (ii) acute stroke theranostics, and (iii) characterization of post-stroke recovery mechanisms. Underlying pathophysiology as it relates to large vessel steno-occlusive disease and the impact of this macrovascular disease on tissue-level viability, hemodynamics (cerebral blood flow, cerebral blood volume, and mean transit time), and metabolism (cerebral metabolic rate of oxygen consumption and pH) are also discussed in the context of emerging neuroimaging protocols with sensitivity to these factors. The overall purpose is to highlight advancements in stroke care and diagnostics and to provide a general overview of emerging research topics that have potential for reducing morbidity in multiple areas of CVD.
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Affiliation(s)
- Manus J Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Eric Achten
- Department of Radiology and Nuclear Medicine, Universiteit Gent, Gent, Belgium
| | - Petrice M Cogswell
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Frank-Erik De Leeuw
- Radboud University, Nijmegen Medical Center, Donders Institute Brain Cognition & Behaviour, Center for Neuroscience, Department of Neurology, Nijmegen, The Netherlands
| | - Colin P Derdeyn
- Department of Radiology and Neurology, University of Iowa, Iowa City, IA, USA
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Audrey P Fan
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Rashid Ghaznawi
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeremy J Heit
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology, Erasmus MC, Rotterdam, The Netherlands
| | - Peter Jezzard
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Lori C Jordan
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Jouvent
- Department of Neurology, AP-HP, Lariboisière Hospital, Paris, France
| | - Linda Knutsson
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Richard Leigh
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | | | - Weili Lin
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Thomas W Okell
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Adnan I Qureshi
- Department of Neurology, Zeenat Qureshi Stroke Institute, St. Cloud, MN, USA
| | - Charlotte J Stagg
- Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK
| | | | - Peter CM van Zijl
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jennifer M Watchmaker
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Max Wintermark
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - Ona Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Greg Zaharchuk
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - Jinyuan Zhou
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
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52
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Lee B, Park JE, Bjørnerud A, Kim JH, Lee JY, Kim HS. Clinical Value of Vascular Permeability Estimates Using Dynamic Susceptibility Contrast MRI: Improved Diagnostic Performance in Distinguishing Hypervascular Primary CNS Lymphoma from Glioblastoma. AJNR Am J Neuroradiol 2018; 39:1415-1422. [PMID: 30026384 DOI: 10.3174/ajnr.a5732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 05/01/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND PURPOSE A small subset of primary central nervous system lymphomas exhibits high cerebral blood volume, which is indistinguishable from that in glioblastoma on dynamic susceptibility contrast MR imaging. Our study aimed to test whether estimates of combined perfusion and vascular permeability metrics derived from DSC-MR imaging can improve the diagnostic performance in differentiating hypervascular primary central nervous system lymphoma from glioblastoma. MATERIALS AND METHODS A total of 119 patients (with 30 primary central nervous system lymphomas and 89 glioblastomas) exhibited hypervascular foci using the reference method of leakage-corrected CBV (reference-normalized CBV). An alternative postprocessing method used the tissue residue function to calculate vascular permeability (extraction fraction), leakage-corrected CBV, cerebral blood flow, and mean transit time. Parameters were compared using Mann-Whitney U tests, and the diagnostic performance to distinguish primary central nervous system lymphoma from glioblastoma was calculated using the area under the curve from the receiver operating characteristic curve and was cross-validated with bootstrapping. RESULTS Hypervascular primary central nervous system lymphoma showed similar leakage-corrected normalized CBV and leakage-corrected CBV compared with glioblastoma (P > .05); however, primary central nervous system lymphoma exhibited a significantly higher extraction fraction (P < .001) and CBF (P = .01) and shorter MTT (P < .001) than glioblastoma. The extraction fraction showed the highest diagnostic performance (the area under the receiver operating characteristic curve [AUC], 0.78; 95% confidence interval, 0.69-0.85) for distinguishing hypervascular primary central nervous system lymphoma from glioblastoma, with a significantly higher performance than both CBV (AUC, 0.53-0.59, largest P = .02) and CBF (AUC, 0.72) and MTT (AUC, 0.71). CONCLUSIONS Estimation of vascular permeability with DSC-MR imaging further characterizes hypervascular primary central nervous system lymphoma and improves diagnostic performance in glioblastoma differentiation.
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Affiliation(s)
- B Lee
- From the Department of Radiology (B.L.), Seoul Metropolitan Government-Seoul National University, Boramae Medical Center, Seoul, Korea
| | - J E Park
- Department of Radiology and Research Institute of Radiology (J.E.P., H.S.K.), University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - A Bjørnerud
- Department of Diagnostic Physics (A.B.), Rikshopitalet University Hospital, Oslo, Norway
| | - J H Kim
- NordicNeuroLab (J.H.K.), Seoul, Korea
| | - J Y Lee
- Department of Radiology (J.Y.L.), Soonchunhyang University Bucheon Hospital, Bucheon, Korea
| | - H S Kim
- Department of Radiology and Research Institute of Radiology (J.E.P., H.S.K.), University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
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53
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Nielsen A, Hansen MB, Tietze A, Mouridsen K. Prediction of Tissue Outcome and Assessment of Treatment Effect in Acute Ischemic Stroke Using Deep Learning. Stroke 2018; 49:1394-1401. [DOI: 10.1161/strokeaha.117.019740] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Treatment options for patients with acute ischemic stroke depend on the volume of salvageable tissue. This volume assessment is currently based on fixed thresholds and single imagine modalities, limiting accuracy. We wish to develop and validate a predictive model capable of automatically identifying and combining acute imaging features to accurately predict final lesion volume.
Methods—
Using acute magnetic resonance imaging, we developed and trained a deep convolutional neural network (CNN
deep
) to predict final imaging outcome. A total of 222 patients were included, of which 187 were treated with rtPA (recombinant tissue-type plasminogen activator). The performance of CNN
deep
was compared with a shallow CNN based on the perfusion-weighted imaging biomarker Tmax (CNN
Tmax
), a shallow CNN based on a combination of 9 different biomarkers (CNN
shallow
), a generalized linear model, and thresholding of the diffusion-weighted imaging biomarker apparent diffusion coefficient (ADC) at 600×10
−6
mm
2
/s (ADC
thres
). To assess whether CNN
deep
is capable of differentiating outcomes of ±intravenous rtPA, patients not receiving intravenous rtPA were included to train CNN
deep,
−rtpa
to access a treatment effect. The networks’ performances were evaluated using visual inspection, area under the receiver operating characteristic curve (AUC), and contrast.
Results—
CNN
deep
yields significantly better performance in predicting final outcome (AUC=0.88±0.12) than generalized linear model (AUC=0.78±0.12;
P
=0.005), CNN
Tmax
(AUC=0.72±0.14;
P
<0.003), and ADC
thres
(AUC=0.66±0.13;
P
<0.0001) and a substantially better performance than CNN
shallow
(AUC=0.85±0.11;
P
=0.063). Measured by contrast, CNN
deep
improves the predictions significantly, showing superiority to all other methods (
P
≤0.003). CNN
deep
also seems to be able to differentiate outcomes based on treatment strategy with the volume of final infarct being significantly different (
P
=0.048).
Conclusions—
The considerable prediction improvement accuracy over current state of the art increases the potential for automated decision support in providing recommendations for personalized treatment plans.
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Affiliation(s)
- Anne Nielsen
- From the Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLAB, Aarhus University, Denmark (A.N., M.B.H., A.T., K.M.)
- Cercare Medical ApS, Aarhus, Denmark (A.N.)
| | - Mikkel Bo Hansen
- From the Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLAB, Aarhus University, Denmark (A.N., M.B.H., A.T., K.M.)
| | - Anna Tietze
- From the Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLAB, Aarhus University, Denmark (A.N., M.B.H., A.T., K.M.)
- Institute of Neuroradiology, Charité Universitätsmedizin, Germany (A.T.)
| | - Kim Mouridsen
- From the Department of Clinical Medicine, Center of Functionally Integrative Neuroscience and MINDLAB, Aarhus University, Denmark (A.N., M.B.H., A.T., K.M.)
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Quarles CC, Bell LC, Stokes AM. Imaging vascular and hemodynamic features of the brain using dynamic susceptibility contrast and dynamic contrast enhanced MRI. Neuroimage 2018; 187:32-55. [PMID: 29729392 DOI: 10.1016/j.neuroimage.2018.04.069] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 04/27/2018] [Accepted: 04/29/2018] [Indexed: 12/22/2022] Open
Abstract
In the context of neurologic disorders, dynamic susceptibility contrast (DSC) and dynamic contrast enhanced (DCE) MRI provide valuable insights into cerebral vascular function, integrity, and architecture. Even after two decades of use, these modalities continue to evolve as their biophysical and kinetic basis is better understood, with improvements in pulse sequences and accelerated imaging techniques and through application of more robust and automated data analysis strategies. Here, we systematically review each of these elements, with a focus on how their integration improves kinetic parameter accuracy and the development of new hemodynamic biomarkers that provide sub-voxel sensitivity (e.g., capillary transit time and flow heterogeneity). Regarding contrast mechanisms, we discuss the dipole-dipole interactions and susceptibility effects that give rise to simultaneous T1, T2 and T2∗ relaxation effects, including their quantification, influence on pulse sequence parameter optimization, and use in methods such as vessel size and vessel architectural imaging. The application of technologic advancements, such as parallel imaging, simultaneous multi-slice, undersampled k-space acquisitions, and sliding window strategies, enables improved spatial and/or temporal resolution of DSC and DCE acquisitions. Such acceleration techniques have also enabled the implementation of, clinically feasible, simultaneous multi-echo spin- and gradient echo acquisitions, providing more comprehensive and quantitative interrogation of T1, T2 and T2∗ changes. Characterizing these relaxation rate changes through different post-processing options allows for the quantification of hemodynamics and vascular permeability. The application of different biophysical models provides insight into traditional hemodynamic parameters (e.g., cerebral blood volume) and more advanced parameters (e.g., capillary transit time heterogeneity). We provide insight into the appropriate selection of biophysical models and the necessary post-processing steps to ensure reliable measurements while minimizing potential sources of error. We show representative examples of advanced DSC- and DCE-MRI methods applied to pathologic conditions affecting the cerebral microcirculation, including brain tumors, stroke, aging, and multiple sclerosis. The maturation and standardization of conventional DSC- and DCE-MRI techniques has enabled their increased integration into clinical practice and use in clinical trials, which has, in turn, spurred renewed interest in their technological and biophysical development, paving the way towards a more comprehensive assessment of cerebral hemodynamics.
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Affiliation(s)
- C Chad Quarles
- Division of Neuro imaging Research, Barrow Neurological Institute, 350 W. Thomas Rd, Phoenix, AZ, USA.
| | - Laura C Bell
- Division of Neuro imaging Research, Barrow Neurological Institute, 350 W. Thomas Rd, Phoenix, AZ, USA
| | - Ashley M Stokes
- Division of Neuro imaging Research, Barrow Neurological Institute, 350 W. Thomas Rd, Phoenix, AZ, USA
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55
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Arsava EM, Hansen MB, Kaplan B, Peker A, Gocmen R, Arat A, Oguz KK, Topcuoglu MA, Østergaard L, Dalkara T. The effect of carotid artery stenting on capillary transit time heterogeneity in patients with carotid artery stenosis. Eur Stroke J 2018; 3:263-271. [PMID: 31008357 DOI: 10.1177/2396987318772686] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/01/2018] [Indexed: 11/17/2022] Open
Abstract
Introduction Carotid revascularisation improves haemodynamic compromise in cerebral circulation as an additional benefit to the primary goal of reducing future thromboembolic risk. We determined the effect of carotid artery stenting on cerebral perfusion and oxygenation using a perfusion-weighted MRI algorithm that is based on assessment of capillary transit-time heterogeneity together with other perfusion and metabolism-related metrics. Patients and methods A consecutive series of 33 patients were evaluated by dynamic susceptibility contrast perfusion-weighted MRI prior to and within 24 h of the endovascular procedure. The level of relative change induced by stenting, and relationship of these changes with respect to baseline stenosis degree were analysed. Results Stenting led to significant increase in cerebral blood flow (p < 0.001), and decrease in cerebral blood volume (p = 0.001) and mean transit time (p < 0.001); this was accompanied by reduction in oxygen extraction fraction (p < 0.001) and capillary transit-time heterogeneity (p < 0.001), but an overall increase in relative capillary transit-time heterogeneity (RTH: CTH divided by MTT; p = 0.008). No significant change was observed with respect to cerebral metabolic rate of oxygen. The median volume of tissue with MTT > 2s decreased from 24 ml to 12 ml (p = 0.009), with CTH > 2s from 29 ml to 19 ml (p = 0.041), and with RTH < 0.9 from 61 ml to 39 ml (p = 0.037) following stenting. These changes were correlated with the baseline degree of stenosis.Discussion: Stenting improved the moderate stage of haemodynamic compromise at baseline in our cohort. The decreased relative transit-time heterogeneity, which increases following stenting, is probably a reflection of decreased functional capillary density secondary to chronic hypoperfusion induced by the proximal stenosis.Conclusion: Carotid artery stenting, is not only important for prophylaxis of future vascular events, but also is critical for restoration of microvascular function in the cerebral tissue.
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Affiliation(s)
- Ethem M Arsava
- Department of Neurology, Faculty of Medicine, Hacettepe University, Turkey
| | - Mikkel B Hansen
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
| | - Berkan Kaplan
- Department of Neurology, Faculty of Medicine, Hacettepe University, Turkey
| | - Ahmet Peker
- Department of Radiology, Faculty of Medicine, Hacettepe University, Turkey
| | - Rahsan Gocmen
- Department of Radiology, Faculty of Medicine, Hacettepe University, Turkey
| | - Anil Arat
- Department of Radiology, Faculty of Medicine, Hacettepe University, Turkey
| | - Kader K Oguz
- Department of Radiology, Faculty of Medicine, Hacettepe University, Turkey
| | - Mehmet A Topcuoglu
- Department of Neurology, Faculty of Medicine, Hacettepe University, Turkey
| | - Leif Østergaard
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Denmark
| | - Turgay Dalkara
- Department of Neurology, Faculty of Medicine, Hacettepe University, Turkey.,Institute of Neurological Sciences and Psychiatry, Hacettepe University, Turkey
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56
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Taskiran-Sag A, Yemisci M, Gursoy-Ozdemir Y, Erdener SE, Karatas H, Yuce D, Dalkara T. Improving Microcirculatory Reperfusion Reduces Parenchymal Oxygen Radical Formation and Provides Neuroprotection. Stroke 2018; 49:1267-1275. [PMID: 29669868 DOI: 10.1161/strokeaha.118.020711] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 03/17/2018] [Accepted: 03/20/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE Reperfusion is the most significant determinant of good outcome after ischemic stroke. However, complete reperfusion often cannot be achieved, despite satisfactory recanalization. We hypothesized that microvascular protection was essential for achieving effective reperfusion and, hence, neuroprotection. To test this hypothesis, we have developed an in vivo model to differentially monitor parenchymal and vascular reactive oxygen species (ROS) formation. By comparing the ROS-suppressing effect of N-tert-butyl-α-phenylnitrone (PBN) with its blood-brain barrier impermeable analog 2-sulfo-phenyl-N-tert-butylnitrone (S-PBN), we assessed the impact of vascular ROS suppression alone on reperfusion and stroke outcome after recanalization. METHODS The distal middle cerebral artery was occluded for 1 hour by compressing with a micropipette and then recanalized (n=60 Swiss mice). ROS formation was monitored for 1 hour after recanalization by intravital fluorescence microscopy in pial vasculature and cortical parenchyma with topically applied hydroethidine through a cranial window. PBN (100 mg/kg) or S-PBN (156 mg/kg) was administered shortly before recanalization, and suppression of the vascular and parenchymal hydroethidine fluorescence was examined (n=22). Microcirculatory patency, reperfusion, ischemic tissue size, and neurological outcome were also assessed in a separate group of mice 1 to 72 hours after recanalization (n=30). RESULTS PBN and S-PBN completely suppressed the reperfusion-induced increase in ROS signal within vasculature. PBN readily suppressed ROS produced in parenchyma by 88%. S-PBN also suppressed the parenchymal ROS by 64% but starting 40 minutes later. Intriguingly, PBN and S-PBN comparably reduced the size of ischemic area by 65% and 48% (P>0.05), respectively. S-PBN restored the microvascular patency and perfusion after recanalization, suggesting that its delayed parenchymal antioxidant effect could be secondary to improved microcirculatory reperfusion. CONCLUSIONS Promoting microvascular reperfusion by protecting vasculature can secondarily reduce parenchymal ROS formation and provide neuroprotection. The model presented can be used to directly assess pharmacological end points postulated in brain parenchyma and vasculature in vivo.
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Affiliation(s)
- Aslihan Taskiran-Sag
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.)
| | - Muge Yemisci
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.).,Department of Neurology (M.Y., Y.G.-O., T.D.)
| | - Yasemin Gursoy-Ozdemir
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.).,Department of Neurology (M.Y., Y.G.-O., T.D.)
| | - Sefik Evren Erdener
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.)
| | - Hulya Karatas
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.)
| | - Deniz Yuce
- Institute of Cancer (D.Y.), Hacettepe University, Ankara, Turkey
| | - Turgay Dalkara
- From the Institute of Neurological Sciences and Psychiatry (A.T.-S., M.Y., Y.G.-O., S.E.E., H.K., T.D.) .,Department of Neurology (M.Y., Y.G.-O., T.D.)
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57
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Livne M, Boldsen JK, Mikkelsen IK, Fiebach JB, Sobesky J, Mouridsen K. Boosted Tree Model Reforms Multimodal Magnetic Resonance Imaging Infarct Prediction in Acute Stroke. Stroke 2018. [PMID: 29540608 DOI: 10.1161/strokeaha.117.019440] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Stroke imaging is pivotal for diagnosis and stratification of patients with acute ischemic stroke to treatment. The potential of combining multimodal information into reliable estimates of outcome learning calls for robust machine learning techniques with high flexibility and accuracy. We applied the novel extreme gradient boosting algorithm for multimodal magnetic resonance imaging-based infarct prediction. METHODS In a retrospective analysis of 195 patients with acute ischemic stroke, fluid-attenuated inversion recovery, diffusion-weighted imaging, and 10 perfusion parameters were derived from acute magnetic resonance imaging scans. They were integrated to predict final infarct as seen on follow-up T2-fluid-attenuated inversion recovery using the extreme gradient boosting and compared with a standard generalized linear model approach using cross-validation. Submodels for recanalization and persistent occlusion were calculated and were used to identify the important imaging markers. Performance in infarct prediction was analyzed with receiver operating characteristics. Resulting areas under the curve and accuracy rates were compared using Wilcoxon signed-rank test. RESULTS The extreme gradient boosting model demonstrated significantly higher performance in infarct prediction compared with generalized linear model in both cross-validation approaches: 5-folds (P<10e-16) and leave-one-out (P<0.015). The imaging parameters time-to-peak, mean transit time, time-to-maximum, and diffusion-weighted imaging were indicated as most valuable for infarct prediction by the systematic algorithm rating. Notably, the performance improvement was higher with 5-folds cross-validation approach than leave-one-out. CONCLUSIONS We demonstrate extreme gradient boosting as a state-of-the-art method for clinically applicable multimodal magnetic resonance imaging infarct prediction in acute ischemic stroke. Our findings emphasize the role of perfusion parameters as important biomarkers for infarct prediction. The effect of cross-validation techniques on performance indicates that the intrapatient variability is expressed in nonlinear dynamics of the imaging modalities.
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Affiliation(s)
- Michelle Livne
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.).
| | - Jens K Boldsen
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.)
| | - Irene K Mikkelsen
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.)
| | - Jochen B Fiebach
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.)
| | - Jan Sobesky
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.)
| | - Kim Mouridsen
- From the Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Germany (M.L., J.B.F., J.S.); and Center of Functionally Integrative Neuroscience, Aarhus University, Denmark (J.K.B., I.K.M., K.M.)
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58
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Angleys H, Jespersen SN, Østergaard L. The effects of capillary transit time heterogeneity on the BOLD signal. Hum Brain Mapp 2018; 39:2329-2352. [PMID: 29498762 DOI: 10.1002/hbm.23991] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 12/06/2017] [Accepted: 01/23/2018] [Indexed: 12/18/2022] Open
Abstract
Neurovascular coupling mechanisms give rise to vasodilation and functional hyperemia upon neural activation, thereby altering blood oxygenation. This blood oxygenation level dependent (BOLD) contrast allows studies of activation patterns in the working human brain by functional MRI (fMRI). The BOLD-weighted fMRI signal shows characteristic transients in relation to functional activation, such as the so-called initial dip, overshoot, and post-stimulus undershoot. These transients are modulated by other physiological stimuli and in disease, but the underlying physiological mechanisms remain incompletely understood. Capillary transit time heterogeneity (CTH) has been shown to affect oxygen extraction, and hence blood oxygenation. Here, we examine how recently reported redistributions of capillary blood flow during functional activation would be expected to affect BOLD signal transients. We developed a three-compartment (hemoglobin, plasma, and tissue) model to predict the BOLD signal, incorporating the effects of dynamic changes in CTH. Our model predicts that the BOLD signal represents the superposition of a positive component resulting from increases in cerebral blood flow (CBF), and a negative component, resulting from elevated tissue metabolism and homogenization of capillary flows (reduced CTH). The model reproduces salient features of BOLD signal dynamics under conditions such as hypercapnia, hyperoxia, and caffeine intake, where both brain physiology and BOLD characteristics are altered. Neuroglial signaling and metabolism could affect CBF and capillary flow patterns differently. Further studies of neurovascular and neuro-capillary coupling mechanisms may help us relate BOLD signals to the firing of certain neuronal populations based on their respective BOLD "fingerprints."
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Affiliation(s)
- Hugo Angleys
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark
| | - Sune N Jespersen
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark.,Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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59
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Stadlbauer A, Mouridsen K, Doerfler A, Bo Hansen M, Oberndorfer S, Zimmermann M, Buchfelder M, Heinz G, Roessler K. Recurrence of glioblastoma is associated with elevated microvascular transit time heterogeneity and increased hypoxia. J Cereb Blood Flow Metab 2018; 38:422-432. [PMID: 28273720 PMCID: PMC5851132 DOI: 10.1177/0271678x17694905] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Dynamic susceptibility contrast (DSC) perfusion MRI provide information about differences in macro- and microvasculature when executed with gradient-echo (GE; sensitive to macrovasculature) and spin-echo (SE; sensitive to microvasculature) contrast. This study investigated whether there are differences between macro- and microvascular transit time heterogeneity (MVTH and µVTH) and tissue oxygen tension (PO2mit) in newly-diagnosed and recurrent glioblastoma. Fifty-seven patients with glioblastoma (25 newly-diagnosed/32 recurrent) were examined with GE- and SE-DSC perfusion sequences, and a quantitative blood-oxygen-level-dependent (qBOLD) approach. Maps of MVTH, µVTH and coefficient of variation (MCOV and µCOV) were calculated from GE- and SE-DSC data, respectively, using an extended flow-diffusion equation. PO2mit maps were calculated from qBOLD data. Newly-diagnosed and recurrent glioblastoma showed significantly lower ( P ≤ 0.001) µCOV values compared to both normal brain and macrovasculature (MCOV) of the lesions. Recurrent glioblastoma had significantly higher µVTH ( P = 0.014) and µCOV ( P = 0.039) as well as significantly lower PO2mit values ( P = 0.008) compared to newly-diagnosed glioblastoma. The macrovasculature, however, showed no significant differences. Our findings provide evidence of microvascular adaption in the disorganized tumor vasculature for retaining the metabolic demands in stress response of therapeutically-uncontrolled glioblastomas. Thus, µVTH and PO2mit mapping gives insight into the tumor microenvironment (vascular and hypoxic niches) responsible for therapy resistance.
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Affiliation(s)
- Andreas Stadlbauer
- 1 Department of Neurosurgery, University of Erlangen-Nürnberg, Erlangen, Germany.,2 Institute of Medical Radiology, University Clinic of St. Pölten, St. Pölten, Austria
| | - Kim Mouridsen
- 3 Center of Functionally Integrative Neuroscience and MIND Lab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Arnd Doerfler
- 4 Department of Neuroradiology, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Mikkel Bo Hansen
- 3 Center of Functionally Integrative Neuroscience and MIND Lab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Stefan Oberndorfer
- 5 Department of Neurology, University Clinic of St. Pölten, St. Pölten, Austria
| | - Max Zimmermann
- 1 Department of Neurosurgery, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Buchfelder
- 1 Department of Neurosurgery, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Gertraud Heinz
- 2 Institute of Medical Radiology, University Clinic of St. Pölten, St. Pölten, Austria
| | - Karl Roessler
- 1 Department of Neurosurgery, University of Erlangen-Nürnberg, Erlangen, Germany
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60
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Lauer A, Da X, Hansen MB, Boulouis G, Ou Y, Cai X, Liberato Celso Pedrotti A, Kalpathy-Cramer J, Caruso P, Hayden DL, Rost N, Mouridsen K, Eichler FS, Rosen B, Musolino PL. ABCD1 dysfunction alters white matter microvascular perfusion. Brain 2017; 140:3139-3152. [PMID: 29136088 PMCID: PMC5841142 DOI: 10.1093/brain/awx262] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022] Open
Abstract
Cerebral X-linked adrenoleukodystrophy is a devastating neurodegenerative disorder caused by mutations in the ABCD1 gene, which lead to a rapidly progressive cerebral inflammatory demyelination in up to 60% of affected males. Selective brain endothelial dysfunction and increased permeability of the blood–brain barrier suggest that white matter microvascular dysfunction contributes to the conversion to cerebral disease. Applying a vascular model to conventional dynamic susceptibility contrast magnetic resonance perfusion imaging, we demonstrate that lack of ABCD1 function causes increased capillary flow heterogeneity in asymptomatic hemizygotes predominantly in the white matter regions and developmental stages with the highest probability for conversion to cerebral disease. In subjects with ongoing inflammatory demyelination we observed a sequence of increased capillary flow heterogeneity followed by blood–brain barrier permeability changes in the perilesional white matter, which predicts lesion progression. These white matter microvascular alterations normalize within 1 year after treatment with haematopoietic stem cell transplantation. For the first time in vivo, our studies unveil a model to assess how ABCD1 alters white matter microvascular function and explores its potential as an earlier biomarker for monitoring disease progression and response to treatment.
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Affiliation(s)
- Arne Lauer
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Department of Neuroradiology, Goethe University, Frankfurt a.M., Germany
| | - Xiao Da
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | | | - Gregoire Boulouis
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Department of Neuroradiology, Université Paris-Descartes, INSERM UMR 894, Centre Hospitalier Sainte-Anne, Paris, France
| | - Yangming Ou
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Boston, MA, USA
| | - Xuezhu Cai
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | | | | | - Paul Caruso
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Douglas L Hayden
- Department of Biostatistics, Massachusetts General Hospital, Boston, MA, USA
| | - Natalia Rost
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Kim Mouridsen
- Department of Clinical Medicine, Aarhus University, Denmark
| | - Florian S Eichler
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | - Bruce Rosen
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Patricia L Musolino
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
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61
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Koch KU, Tietze A, Aanerud J, Öettingen GV, Juul N, Sørensen JCH, Nikolajsen L, Østergaard L, Rasmussen M. Effect of ephedrine and phenylephrine on brain oxygenation and microcirculation in anaesthetised patients with cerebral tumours: study protocol for a randomised controlled trial. BMJ Open 2017; 7:e018560. [PMID: 29151054 PMCID: PMC5701991 DOI: 10.1136/bmjopen-2017-018560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION During brain tumour surgery, vasopressor drugs are commonly administered to increase mean arterial blood pressure with the aim of maintaining sufficient cerebral perfusion pressure. Studies of the commonly used vasopressors show that brain oxygen saturation is reduced after phenylephrine administration, but unaltered by ephedrine administration. These findings may be explained by different effects of phenylephrine and ephedrine on the cerebral microcirculation, in particular the capillary transit-time heterogeneity, which determines oxygen extraction efficacy. We hypothesised that phenylephrine is associated with an increase in capillary transit-time heterogeneity and a reduction in cerebral metabolic rate of oxygen compared with ephedrine. Using MRI and positron emission tomography (PET) as measurements in anaesthetised patients with brain tumours, this study will examine whether phenylephrine administration elevates capillary transit-time heterogeneity more than ephedrine, thereby reducing brain oxygenation. METHODS AND ANALYSIS This is a double-blind, randomised clinical trial including 48 patients scheduled for surgical brain tumour removal. Prior to imaging and surgery, anaesthetised patients will be randomised to receive either phenylephrine or ephedrine infusion until mean arterial blood pressure increases to above 60 mm Hg or 20% above baseline. Twenty-four patients were allocated to MRI and another 24 patients to PET examination. MRI measurements include cerebral blood flow, capillary transit-time heterogeneity, cerebral blood volume, blood mean transit time, and calculated oxygen extraction fraction and cerebral metabolic rate of oxygen for negligible tissue oxygen extraction. PET measurements include cerebral metabolic rate of oxygen, cerebral blood flow and oxygen extraction fraction. Surgery is initiated after MRI/PET measurements and subdural intracranial pressure is measured. ETHICS AND DISSEMINATION This study was approved by the Central Denmark Region Committee on Health Research Ethics (12 June 2015; 1-10-72-116-15). Results will be disseminated via peer-reviewed publication and presentation at international conferences. TRIAL REGISTRATION NUMBER NCT02713087; Pre-results. 2015-001359-60; Pre-results.
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Affiliation(s)
- Klaus Ulrik Koch
- Department of Anesthesiology and Intensive Care-North, Section of Neuroanesthesia, Aarhus University Hospital, Aarhus, Denmark
| | - Anna Tietze
- Department of Neuroradiology and Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark
- Institute of Neuroradiology, Charite Universitatsmedizin, Berlin, Germany
| | - Joel Aanerud
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | | | - Niels Juul
- Department of Anesthesiology and Intensive Care-North, Section of Neuroanesthesia, Aarhus University Hospital, Aarhus, Denmark
| | | | - Lone Nikolajsen
- Department of Anesthesiology and Intensive Care-North, Section of Neuroanesthesia, Aarhus University Hospital, Aarhus, Denmark
| | - Leif Østergaard
- Department of Neuroradiology and Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark
| | - Mads Rasmussen
- Department of Anesthesiology and Intensive Care-North, Section of Neuroanesthesia, Aarhus University Hospital, Aarhus, Denmark
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Disturbances in the control of capillary flow in an aged APP swe/PS1ΔE9 model of Alzheimer's disease. Neurobiol Aging 2017; 62:82-94. [PMID: 29131981 DOI: 10.1016/j.neurobiolaging.2017.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 02/08/2023]
Abstract
Vascular changes are thought to contribute to the development of Alzheimer's disease, and both cerebral blood flow and its responses during neural activation are reduced before Alzheimer's disease symptoms onset. One hypothetical explanation is that capillary dysfunction reduces oxygen extraction efficacy. This study compares the morphology and hemodynamics of the microvasculature in the somatosensory cortex of 18-month-old APPSWE/PS1ΔE9 (transgenic [Tg]) mice and wild-type (WT) littermates. In particular, the extent to which their capillary transit times homogenize during functional activation was measured and compared. Capillary length density was similar in both groups but capillary blood flow during rest was lower in the Tg mice, indicating that cortical oxygen availability is reduced. The capillary hemodynamic response to functional activation was larger, and lasted longer in Tg mice than in WT mice. The homogenization of capillary transit times during functional activation, which we previously demonstrated in young mice, was absent in the Tg mice. This study demonstrates that both neurovascular coupling and capillary function are profoundly disturbed in aged Tg and WT mice.
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63
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Digernes I, Bjørnerud A, Vatnehol SAS, Løvland G, Courivaud F, Vik-Mo E, Meling TR, Emblem KE. A theoretical framework for determining cerebral vascular function and heterogeneity from dynamic susceptibility contrast MRI. J Cereb Blood Flow Metab 2017; 37:2237-2248. [PMID: 28273722 PMCID: PMC5444554 DOI: 10.1177/0271678x17694187] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mapping the complex heterogeneity of vascular tissue in the brain is important for understanding cerebrovascular disease. In this translational study, we build on previous work using vessel architectural imaging (VAI) and present a theoretical framework for determining cerebral vascular function and heterogeneity from dynamic susceptibility contrast magnetic resonance imaging (MRI). Our tissue model covers realistic structural architectures for vessel branching and orientations, as well as a range of hemodynamic scenarios for blood flow, capillary transit times and oxygenation. In a typical image voxel, our findings show that the apparent MRI relaxation rates are independent of the mean vessel orientation and that the vortex area, a VAI-based parameter, is determined by the relative oxygen saturation level and the vessel branching of the tissue. Finally, in both simulated and patient data, we show that the relative distributions of the vortex area parameter as a function of capillary transit times show unique characteristics in normal-appearing white and gray matter tissue, whereas tumour-voxels in comparison display a heterogeneous distribution. Collectively, our study presents a comprehensive framework that may serve as a roadmap for in vivo and per-voxel determination of vascular status and heterogeneity in cerebral tissue.
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Affiliation(s)
- Ingrid Digernes
- 1 Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
| | - Atle Bjørnerud
- 1 Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.,2 Department of Physics, University of Oslo, Oslo, Norway
| | | | - Grete Løvland
- 1 Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
| | - Frédéric Courivaud
- 1 Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
| | - Einar Vik-Mo
- 3 Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
| | - Torstein R Meling
- 3 Department of Neurosurgery, Oslo University Hospital, Oslo, Norway.,4 Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kyrre E Emblem
- 1 Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway
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64
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Nielsen RB, Egefjord L, Angleys H, Mouridsen K, Gejl M, Møller A, Brock B, Brændgaard H, Gottrup H, Rungby J, Eskildsen SF, Østergaard L. Capillary dysfunction is associated with symptom severity and neurodegeneration in Alzheimer's disease. Alzheimers Dement 2017; 13:1143-1153. [PMID: 28343848 DOI: 10.1016/j.jalz.2017.02.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/13/2017] [Accepted: 02/13/2017] [Indexed: 01/18/2023]
Abstract
INTRODUCTION We examined whether cortical microvascular blood volume and hemodynamics in Alzheimer's disease (AD) are consistent with tissue hypoxia and whether they correlate with cognitive performance and the degree of cortical thinning. METHODS Thirty-two AD patients underwent cognitive testing, structural magnetic resonance imaging (MRI), and perfusion MRI at baseline and after 6 months. We measured cortical thickness, microvascular cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and capillary transit time heterogeneity (CTH) and estimated tissue oxygen tension (PtO2). RESULTS At baseline, poor cognitive performance and regional cortical thinning correlated with lower CBF and CBV, with higher MTT and CTH and with low PtO2 across the cortex. Cognitive decline over time was associated with increasing whole brain relative transit time heterogeneity (RTH = CTH/MTT). DISCUSSION Our results confirm the importance of microvascular pathology in AD. Deteriorating microvascular hemodynamics may cause hypoxia, which is known to precipitate amyloid retention.
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Affiliation(s)
- Rune B Nielsen
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark.
| | - Lærke Egefjord
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Hugo Angleys
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark
| | - Michael Gejl
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Arne Møller
- PET-Center, Department of Nuclear Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Birgitte Brock
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Hans Brændgaard
- Dementia Clinic, Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Hanne Gottrup
- Dementia Clinic, Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Jørgen Rungby
- Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Simon F Eskildsen
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark; Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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65
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Increased cortical capillary transit time heterogeneity in Alzheimer's disease: a DSC-MRI perfusion study. Neurobiol Aging 2017; 50:107-118. [DOI: 10.1016/j.neurobiolaging.2016.11.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/17/2016] [Accepted: 11/11/2016] [Indexed: 01/18/2023]
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66
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Bonekamp D, Mouridsen K, Radbruch A, Kurz FT, Eidel O, Wick A, Schlemmer HP, Wick W, Bendszus M, Østergaard L, Kickingereder P. Assessment of tumor oxygenation and its impact on treatment response in bevacizumab-treated recurrent glioblastoma. J Cereb Blood Flow Metab 2017; 37:485-494. [PMID: 26861817 PMCID: PMC5381446 DOI: 10.1177/0271678x16630322] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antiantiogenic therapy with bevacizumab in recurrent glioblastoma is currently understood to both reduce microvascular density and to prune abnormal tumor microvessels. Microvascular pruning and the resulting vascular normalization are hypothesized to reduce tumor hypoxia and increase supply of systemic therapy to the tumor; however, the underlying pathophysiological changes and their timing after treatment initiation remain controversial. Here, we use a novel dynamic susceptibility contrast MRI-based method, which allows simultaneous assessment of tumor net oxygenation changes reflected by the tumor metabolic rate of oxygen and vascular normalization represented by the capillary transit time heterogeneity. We find that capillary transit time heterogeneity, and hence the oxygen extraction fraction combine with the tumoral blood flow (cerebral blood flow) in such a way that the overall tumor oxygenation appears to be worsened despite vascular normalization. Accordingly, hazards for both progression and death are found elevated in patients with a greater reduction of tumor metabolic rate of oxygen in response to bevacizumab and patients with higher intratumoral tumor metabolic rate of oxygen at baseline. This implies that tumors with a higher degree of angiogenesis prior to bevacizumab-treatment retain a higher level of angiogenesis during therapy despite a greater antiangiogenic effect of bevacizumab, hinting at evasive mechanisms limiting bevacizumab efficacy in that a reversal of their biological behavior and relative prognosis does not occur.
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Affiliation(s)
- David Bonekamp
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.,2 Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kim Mouridsen
- 3 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University Hospital, Aarhus, Denmark
| | - Alexander Radbruch
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.,2 Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felix T Kurz
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Oliver Eidel
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Antje Wick
- 4 Neurology Clinic, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- 2 Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Wolfgang Wick
- 4 Neurology Clinic, University of Heidelberg Medical Center, Heidelberg, Germany.,5 Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Bendszus
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
| | - Leif Østergaard
- 3 Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University Hospital, Aarhus, Denmark.,6 Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Philipp Kickingereder
- 1 Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany
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Gutiérrez-Jiménez E, Cai C, Mikkelsen IK, Rasmussen PM, Angleys H, Merrild M, Mouridsen K, Jespersen SN, Lee J, Iversen NK, Sakadzic S, Østergaard L. Effect of electrical forepaw stimulation on capillary transit-time heterogeneity (CTH). J Cereb Blood Flow Metab 2016; 36:2072-2086. [PMID: 26858243 PMCID: PMC5363666 DOI: 10.1177/0271678x16631560] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/26/2015] [Accepted: 12/23/2015] [Indexed: 11/16/2022]
Abstract
Functional hyperemia reduces oxygen extraction efficacy unless counteracted by a reduction of capillary transit-time heterogeneity of blood. We adapted a bolus tracking approach to capillary transit-time heterogeneity estimation for two-photon microscopy and then quantified changes in plasma mean transit time and capillary transit-time heterogeneity during forepaw stimulation in anesthetized mice (C57BL/6NTac). In addition, we analyzed transit time coefficient of variance = capillary transit-time heterogeneity/mean transit time, which we expect to remain constant in passive, compliant microvascular networks. Electrical forepaw stimulation reduced, both mean transit time (11.3% ± 1.3%) and capillary transit-time heterogeneity (24.1% ± 3.3%), consistent with earlier literature and model predictions. We observed a coefficient of variance reduction (14.3% ± 3.5%) during functional activation, especially for the arteriolar-to-venular passage. Such coefficient of variance reduction during functional activation suggests homogenization of capillary flows beyond that expected as a passive response to increased blood flow by other stimuli. This finding is consistent with an active neurocapillary coupling mechanism, for example via pericyte dilation. Mean transit time and capillary transit-time heterogeneity reductions were consistent with the relative change inferred from capillary hemodynamics (cell velocity and flux). Our findings support the important role of capillary transit-time heterogeneity in flow-metabolism coupling during functional activation.
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Affiliation(s)
| | - Changsi Cai
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | | | - Hugo Angleys
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Mads Merrild
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Kim Mouridsen
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Sune Nørhøj Jespersen
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Jonghwan Lee
- Department of Radiology, Harvard Medical School, Boston, USA
| | | | - Sava Sakadzic
- Department of Radiology, Harvard Medical School, Boston, USA
| | - Leif Østergaard
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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68
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Hansen MB, Tietze A, Kalpathy-Cramer J, Gerstner ER, Batchelor TT, Østergaard L, Mouridsen K. Reliable estimation of microvascular flow patterns in patients with disrupted blood-brain barrier using dynamic susceptibility contrast MRI. J Magn Reson Imaging 2016; 46:537-549. [PMID: 27902858 DOI: 10.1002/jmri.25549] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 10/27/2016] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To present and quantify the performance of a method to compute tissue hemodynamic parameters from dynamic susceptibility contrast (DSC) MRI data in brain tissue with possible nonintact blood-brain barrier. THEORY AND MATERIALS AND METHODS We propose a Bayesian scheme to obtain perfusion metrics, including capillary transit-time heterogeneity (CTH), from DSC-MRI data in the presence of contrast agent extravasation. Initial performance assessment is performed through simulations. Next, we assessed possible over- or under correction for tracer extravasation in two patients receiving contrast agent preloading and two patients not receiving preloading. Perfusion metrics for N = 60 patients diagnosed with either grade III (N = 14) or grade IV gliomas (N = 46) were analyzed across tissue types to evaluate the ability to distinguish regions with different hemodynamic patterns. Finally, N = 4 patient cases undergoing anti-angiogenic treatment are evaluated qualitatively for treatment effects. All patient data were acquired at 3.0 Tesla. RESULTS The simulation studies showed good robustness against low signal-to-noise ratios, exemplified with Pearson correlations of R = 0.833 (mean transit time) and R = 0.738 (CTH) at signal-to-noise ratio = 20. Region-of-interest analysis of the N = 60 glioma patients showed that cerebral blood volume (CBV) significantly separated enhancing core from edema (grade IV: P < 10-8 , grade III: P < 0.05) and enhancing core from normal appearing ipsilateral white matter (NAWM) (grade IV: P < 10-8 , grade III: P < 0.05). The microvascular parameters were particularly good in separating edematous tissue from NAWM tissue in grade IV gliomas (P < 0.001). Finally, CTH separated grade III and grade IV core tissue (P < 0.05). CONCLUSION We have demonstrated robustness of the proposed Bayesian algorithm against experimental noise and demonstrated complementary value in microvascular parameters to the CBV parameter in separating tissue types in gliomas. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:537-549.
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Affiliation(s)
- Mikkel Bo Hansen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anna Tietze
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark.,Institute of Neuroradiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117, Berlin
| | - Jayashree Kalpathy-Cramer
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Elizabeth R Gerstner
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Tracy T Batchelor
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
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69
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Kunze KP, Rischpler C, Hayes C, Ibrahim T, Laugwitz KL, Haase A, Schwaiger M, Nekolla SG. Measurement of extracellular volume and transit time heterogeneity using contrast-enhanced myocardial perfusion MRI in patients after acute myocardial infarction. Magn Reson Med 2016; 77:2320-2330. [PMID: 27364875 DOI: 10.1002/mrm.26320] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/17/2016] [Accepted: 05/31/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE To assess the ability of dynamic contrast-enhanced myocardial perfusion MRI to measure extracellular volume (ECV) and to investigate the possibility of estimating capillary transit time heterogeneity (CTH) in patients after myocardial infarction and successful revascularization. METHODS Twenty-four perfusion data sets were acquired on a 3 Tesla positron emission tomography (PET)/MRI scanner. Three perfusion models of different complexity were implemented in a hierarchical fashion with an Akaike information criterion being used to determine the number of fit parameters supported by the data. Results were compared sector-wise to ECV from an equilibrium T1 mapping method (modified look-locker inversion recovery (MOLLI)). RESULTS ECV derived from the perfusion analysis correlated well with equilibrium measurements (R² = 0.76). Estimation of CTH was supported in 16% of sectors (mostly remote). Inclusion of a nonzero CTH parameter usually led to lower estimates of first-pass extraction and slightly higher estimates of blood volume and flow. Estimation of the capillary permeability-surface area product was feasible in 81% of sectors. CONCLUSION Transit time heterogeneity has a measurable effect on the kinetic analysis of myocardial perfusion MRI data, and Gd-DTPA extravasation in the myocardium is usually not flow-limited in infarct-related pathology. Measurement of myocardial ECV using perfusion imaging could provide a scan-time efficient alternative to methods based on T1 mapping. Magn Reson Med 77:2320-2330, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Karl P Kunze
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany
| | - Christoph Rischpler
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | | | - Tareq Ibrahim
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Karl-Ludwig Laugwitz
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Axel Haase
- Zentralinstitut für Medizintechnik (IMETUM) der TU München, Garching, Germany
| | - Markus Schwaiger
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | - Stephan G Nekolla
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
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70
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Mundiyanapurath S, Ringleb PA, Diatschuk S, Hansen MB, Mouridsen K, Østergaard L, Wick W, Bendszus M, Radbruch A. Capillary Transit Time Heterogeneity Is Associated with Modified Rankin Scale Score at Discharge in Patients with Bilateral High Grade Internal Carotid Artery Stenosis. PLoS One 2016; 11:e0158148. [PMID: 27336668 PMCID: PMC4919050 DOI: 10.1371/journal.pone.0158148] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/11/2016] [Indexed: 11/18/2022] Open
Abstract
Background and Purpose Perfusion weighted imaging (PWI) is inherently unreliable in patients with severe perfusion abnormalities. We compared the diagnostic accuracy of a novel index of microvascular flow-patterns, so-called capillary transit time heterogeneity (CTH) to that of the commonly used delay parameter Tmax in patients with bilateral high grade internal carotid artery stenosis (ICAS). Methods Consecutive patients with bilateral ICAS ≥ 70%NASCET who underwent PWI were retrospectively examined. Maps of CTH and Tmax were analyzed with a volumetric approach using several thresholds. Predictors of favorable outcome (modified Rankin scale at discharge 0–2) were identified using univariate and receiver operating characteristic (ROC) curve analysis. Results Eighteen patients were included. CTH ≥ 30s differentiated best between patients with favorable and unfavorable outcome when both hemispheres were taken into account (sensitivity 83%, specificity 73%, area under the curve [AUC] 0.833 [confidence interval (CI) 0.635; 1.000]; p = 0.027). The best discrimination using Tmax was achieved with a threshold of ≥ 4s (sensitivity 83%, specificity 64%, AUC 0.803 [CI 0.585;1.000]; p = 0.044). The highest AUC was found for left sided volume with CTH ≥ 15s (sensitivity 83%, specificity 91%, AUC 0.924 [CI 0.791;1.000]; p = 0.005). Conclusion The study suggests that CTH is superior to Tmax in discriminating ICAS patients with favorable from non-favorable outcome. This finding may reflect the simultaneous involvement of large vessels and microvessels in ICAS and underscore the need to diagnose and manage both aspects of the disease.
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Affiliation(s)
| | | | - Sascha Diatschuk
- German Cancer Research Center, Department of Radiology, Heidelberg, Germany
| | - Mikkel Bo Hansen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Neuroradiology, Aarhus Univesity Hospital, Aarhus, Denmark
| | - Wolfgang Wick
- Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
- CCU Neurooncology, German Cancer Consortium (DKTK) & German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Alexander Radbruch
- German Cancer Research Center, Department of Radiology, Heidelberg, Germany
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail:
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71
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Østergaard L, Engedal TS, Moreton F, Hansen MB, Wardlaw JM, Dalkara T, Markus HS, Muir KW. Cerebral small vessel disease: Capillary pathways to stroke and cognitive decline. J Cereb Blood Flow Metab 2016; 36:302-25. [PMID: 26661176 PMCID: PMC4759673 DOI: 10.1177/0271678x15606723] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 07/30/2015] [Indexed: 01/18/2023]
Abstract
Cerebral small vessel disease (SVD) gives rise to one in five strokes worldwide and constitutes a major source of cognitive decline in the elderly. SVD is known to occur in relation to hypertension, diabetes, smoking, radiation therapy and in a range of inherited and genetic disorders, autoimmune disorders, connective tissue disorders, and infections. Until recently, changes in capillary patency and blood viscosity have received little attention in the aetiopathogenesis of SVD and the high risk of subsequent stroke and cognitive decline. Capillary flow patterns were, however, recently shown to limit the extraction efficacy of oxygen in tissue and capillary dysfunction therefore proposed as a source of stroke-like symptoms and neurodegeneration, even in the absence of physical flow-limiting vascular pathology. In this review, we examine whether capillary flow disturbances may be a shared feature of conditions that represent risk factors for SVD. We then discuss aspects of capillary dysfunction that could be prevented or alleviated and therefore might be of general benefit to patients at risk of SVD, stroke or cognitive decline.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Thorbjørn S Engedal
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Fiona Moreton
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Mikkel B Hansen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Joanna M Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Turgay Dalkara
- Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Hugh S Markus
- Department of Clinical Neuroscience, University of Cambridge, Cambridge, UK
| | - Keith W Muir
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
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72
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Østergaard L, Granfeldt A, Secher N, Tietze A, Iversen NK, Jensen MS, Andersen KK, Nagenthiraja K, Gutiérrez‐Lizardi P, Mouridsen K, Jespersen SN, Tønnesen EK. Microcirculatory dysfunction and tissue oxygenation in critical illness. Acta Anaesthesiol Scand 2015; 59:1246-59. [PMID: 26149711 PMCID: PMC4758388 DOI: 10.1111/aas.12581] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/19/2015] [Accepted: 06/14/2015] [Indexed: 12/19/2022]
Abstract
Severe sepsis is defined by organ failure, often of the kidneys, heart, and brain. It has been proposed that inadequate delivery of oxygen, or insufficient extraction of oxygen in tissue, may explain organ failure. Despite adequate maintenance of systemic oxygen delivery in septic patients, their morbidity and mortality remain high. The assumption that tissue oxygenation can be preserved by maintaining its blood supply follows from physiological models that only apply to tissue with uniformly perfused capillaries. In sepsis, the microcirculation is profoundly disturbed, and the blood supply of individual organs may therefore no longer reflect their access to oxygen. We review how capillary flow patterns affect oxygen extraction efficacy in tissue, and how the regulation of tissue blood flow must be adjusted to meet the metabolic needs of the tissue as capillary flows become disturbed as observed in critical illness. Using the brain, heart, and kidney as examples, we discuss whether disturbed capillary flow patterns might explain the apparent mismatch between organ blood flow and organ function in sepsis. Finally, we discuss diagnostic means of detecting capillary flow disturbance in animal models and in critically ill patients, and address therapeutic strategies that might improve tissue oxygenation by modifying capillary flow patterns.
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Affiliation(s)
- L. Østergaard
- Department of Neuroradiology Aarhus University Hospital Aarhus Denmark
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - A. Granfeldt
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - N. Secher
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - A. Tietze
- Department of Neuroradiology Aarhus University Hospital Aarhus Denmark
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - N. K. Iversen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - M. S. Jensen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - K. K. Andersen
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
| | - K. Nagenthiraja
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - P. Gutiérrez‐Lizardi
- Faculty of Dentistry University of Monterrey Monterrey Mexico
- Critical Care College of Nuevo León Monterrey Mexico
| | - K. Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
| | - S. N. Jespersen
- Center of Functionally Integrative Neuroscience and MINDLab Aarhus University Aarhus Denmark
- Department of Physics and Astronomy Aarhus University Aarhus Denmark
| | - E. K. Tønnesen
- Department of Anaesthesia and Intensive Care Medicine Aarhus University Hospital Aarhus Denmark
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73
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Østergaard L, Jespersen SN, Engedahl T, Gutiérrez Jiménez E, Ashkanian M, Hansen MB, Eskildsen S, Mouridsen K. Capillary dysfunction: its detection and causative role in dementias and stroke. Curr Neurol Neurosci Rep 2015; 15:37. [PMID: 25956993 PMCID: PMC4441906 DOI: 10.1007/s11910-015-0557-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In acute ischemic stroke, critical hypoperfusion is a frequent cause of hypoxic tissue injury: As cerebral blood flow (CBF) falls below the ischemic threshold of 20 mL/100 mL/min, neurological symptoms develop and hypoxic tissue injury evolves within minutes or hours unless the oxygen supply is restored. But is ischemia the only hemodynamic source of hypoxic tissue injury? Reanalyses of the equations we traditionally use to describe the relation between CBF and tissue oxygenation suggest that capillary flow patterns are crucial for the efficient extraction of oxygen: without close capillary flow control, "functional shunts" tend to form and some of the blood's oxygen content in effect becomes inaccessible to tissue. This phenomenon raises several questions: Are there in fact two hemodynamic causes of tissue hypoxia: Limited blood supply (ischemia) and limited oxygen extraction due to capillary dysfunction? If so, how do we distinguish the two, experimentally and in patients? Do flow-metabolism coupling mechanisms adjust CBF to optimize tissue oxygenation when capillary dysfunction impairs oxygen extraction downstream? Cardiovascular risk factors such as age, hypertension, diabetes, hypercholesterolemia, and smoking increase the risk of both stroke and dementia. The capillary dysfunction phenomenon therefore forces us to consider whether changes in capillary morphology or blood rheology may play a role in the etiology of some stroke subtypes and in Alzheimer's disease. Here, we discuss whether certain disease characteristics suggest capillary dysfunction rather than primary flow-limiting vascular pathology and how capillary dysfunction may be imaged and managed.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark,
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74
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Blicher JU, Tietze A, Donahue MJ, Smith SA, Østergaard L. Perfusion and pH MRI in familial hemiplegic migraine with prolonged aura. Cephalalgia 2015; 36:279-83. [DOI: 10.1177/0333102415586064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 04/08/2015] [Indexed: 11/15/2022]
Abstract
Introduction To investigate tissue flow disturbance and hypoxia during migraine aura, we studied a case of familial hemiplegic migraine (FHM) using novel magnetic resonance imaging (MRI) techniques. Case results A 44-year-old male was admitted with suspected stroke because of confusion and aphasia. Initial gadolinium-based perfusion MRI showed a decrease in cerebral blood flow and an increase in capillary flow disturbances within the left hemisphere. Later during the prolonged aura phase, chemical exchange saturation transfer MRI indicated a drop in pH in the affected area. The patient was diagnosed with an R908Q mutation in the ATP1A2 gene causing FHM type 2. Discussion During prolonged aura in FHM, MRI shows reduced CBF, capillary flow disturbances and a possible pH drop that could indicate tissue hypoxia.
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Affiliation(s)
- Jakob Udby Blicher
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
- Department of Neurology, Aarhus University Hospital, Denmark
| | - Anna Tietze
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
| | - Manus J Donahue
- Department of Radiology, Vanderbilt University School of Medicine, USA
- Department of Physics and Astronomy, Vanderbilt University School of Medicine, USA
| | - Seth A Smith
- Department of Radiology, Vanderbilt University School of Medicine, USA
- Department of Physics and Astronomy, Vanderbilt University School of Medicine, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark
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The effects of capillary transit time heterogeneity (CTH) on brain oxygenation. J Cereb Blood Flow Metab 2015; 35:806-17. [PMID: 25669911 PMCID: PMC4420854 DOI: 10.1038/jcbfm.2014.254] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/11/2014] [Accepted: 12/10/2014] [Indexed: 11/09/2022]
Abstract
We recently extended the classic flow-diffusion equation, which relates blood flow to tissue oxygenation, to take capillary transit time heterogeneity (CTH) into account. Realizing that cerebral oxygen availability depends on both cerebral blood flow (CBF) and capillary flow patterns, we have speculated that CTH may be actively regulated and that changes in the capillary morphology and function, as well as in blood rheology, may be involved in the pathogenesis of conditions such as dementia and ischemia-reperfusion injury. The first extended flow-diffusion equation involved simplifying assumptions which may not hold in tissue. Here, we explicitly incorporate the effects of oxygen metabolism on tissue oxygen tension and extraction efficacy, and assess the extent to which the type of capillary transit time distribution affects the overall effects of CTH on flow-metabolism coupling reported earlier. After incorporating tissue oxygen metabolism, our model predicts changes in oxygen consumption and tissue oxygen tension during functional activation in accordance with literature reports. We find that, for large CTH values, a blood flow increase fails to cause significant improvements in oxygen delivery, and can even decrease it; a condition of malignant CTH. These results are found to be largely insensitive to the choice of the transit time distribution.
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76
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Østergaard L, Dreier JP, Hadjikhani N, Jespersen SN, Dirnagl U, Dalkara T. Neurovascular coupling during cortical spreading depolarization and -depression. Stroke 2015; 46:1392-401. [PMID: 25882051 DOI: 10.1161/strokeaha.114.008077] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/17/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Leif Østergaard
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.).
| | - Jens Peter Dreier
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.)
| | - Nouchine Hadjikhani
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.)
| | - Sune Nørhøj Jespersen
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.)
| | - Ulrich Dirnagl
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.)
| | - Turgay Dalkara
- From the Center of Functionally Integrative Neuroscience and MINDLab, Department of Clinical Medicine, Aarhus University, Denmark (L.Ø., S.N.J.); Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark (L.Ø.); Center for Stroke Research and Departments of Experimental Neurology and Neurology, Charité Universitätsmedizin, Berlin, Germany (J.P.D., U.D.); Pathophysiology and Cognition Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Department of Radiology, Harvard Medical School (N.H.); Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark (S.N.J.); and Institute of Neurological Sciences and Psychiatry and Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey (T.D.)
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Perfusion MRI derived indices of microvascular shunting and flow control correlate with tumor grade and outcome in patients with cerebral glioma. PLoS One 2015; 10:e0123044. [PMID: 25875182 PMCID: PMC4395250 DOI: 10.1371/journal.pone.0123044] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 02/20/2015] [Indexed: 01/21/2023] Open
Abstract
Objectives Deficient microvascular blood flow control is thought to cause tumor hypoxia and increase resistance to therapy. In glioma patients, we tested whether perfusion-weighted MRI (PWI) based indices of microvascular flow control provide more information on tumor grade and patient outcome than does the established PWI angiogenesis marker, cerebral blood volume (CBV). Material and Methods Seventy-two glioma patients (sixty high-grade, twelve low-grade gliomas) were included. Capillary transit time heterogeneity (CTH) and the coefficient of variation (COV), its ratio to blood mean transit time, provide indices of microvascular flow control and the extent to which oxygen can be extracted by tumor tissue. The ability of these parameters and CBV to differentiate tumor grade were assessed by receiver operating characteristic curves and logistic regression. Their ability to predict time to progression and overall survival was examined by the Cox proportional-hazards regression model, and by survival curves using log-rank tests. Results The best prediction of grade (AUC = 0.876; p < 0.05) was achieved by combining knowledge of CBV and CTH in the enhancing tumor and peri-focal edema, and patients with glioblastoma multiforme were identified best by CTH (AUC = 0.763; p<0.001). CTH outperformed CBV and COV in predicting time to progression and survival in all gliomas and in a subgroup consisting of only high-grade gliomas. Conclusion Our study confirms the importance of microvascular flow control in tumor growth by demonstrating that determining CTH improves tumor grading and outcome prediction in glioma patients compared to CBV alone.
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78
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Østergaard L, Finnerup NB, Terkelsen AJ, Olesen RA, Drasbek KR, Knudsen L, Jespersen SN, Frystyk J, Charles M, Thomsen RW, Christiansen JS, Beck-Nielsen H, Jensen TS, Andersen H. The effects of capillary dysfunction on oxygen and glucose extraction in diabetic neuropathy. Diabetologia 2015; 58:666-77. [PMID: 25512003 PMCID: PMC4351434 DOI: 10.1007/s00125-014-3461-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 11/06/2014] [Indexed: 12/14/2022]
Abstract
Diabetic neuropathy is associated with disturbances in endoneurial metabolism and microvascular morphology, but the roles of these factors in the aetiopathogenesis of diabetic neuropathy remain unclear. Changes in endoneurial capillary morphology and vascular reactivity apparently predate the development of diabetic neuropathy in humans, and in manifest neuropathy, reductions in nerve conduction velocity correlate with the level of endoneurial hypoxia. The idea that microvascular changes cause diabetic neuropathy is contradicted, however, by reports of elevated endoneurial blood flow in early experimental diabetes, and of unaffected blood flow when early histological signs of neuropathy first develop in humans. We recently showed that disturbances in capillary flow patterns, so-called capillary dysfunction, can reduce the amount of oxygen and glucose that can be extracted by the tissue for a given blood flow. In fact, tissue blood flow must be adjusted to ensure sufficient oxygen extraction as capillary dysfunction becomes more severe, thereby changing the normal relationship between tissue oxygenation and blood flow. This review examines the evidence of capillary dysfunction in diabetic neuropathy, and whether the observed relation between endoneurial blood flow and nerve function is consistent with increasingly disturbed capillary flow patterns. The analysis suggests testable relations between capillary dysfunction, tissue hypoxia, aldose reductase activity, oxidative stress, tissue inflammation and glucose clearance from blood. We discuss the implications of these predictions in relation to the prevention and management of diabetic complications in type 1 and type 2 diabetes, and suggest ways of testing these hypotheses in experimental and clinical settings.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University Hospital, Building 10G, Nørrebrogade 44, DK-8000, Aarhus C, Denmark,
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79
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Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury. J Cereb Blood Flow Metab 2014; 34:1585-98. [PMID: 25052556 PMCID: PMC4269727 DOI: 10.1038/jcbfm.2014.131] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 06/10/2014] [Accepted: 06/20/2014] [Indexed: 12/26/2022]
Abstract
Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of 'classic' ischemia. We discuss diagnostic and therapeutic consequences of these predictions.
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