Elevated brain oxygen extraction fraction measured by MRI susceptibility relates to perfusion status in acute ischemic stroke

Recent clinical trials of new revascularization therapies in acute ischemic stroke have highlighted the importance of physiological imaging to identify optimal treatments for patients. Oxygen extraction fraction (OEF) is a hallmark of at-risk tissue in stroke, and can be quantified from the suscepti...

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Bibliographic Details
Published in:Journal of cerebral blood flow and metabolism 2020-03, Vol.40 (3), p.539-551
Main Authors: Fan, Audrey P, Khalil, Ahmed A, Fiebach, Jochen B, Zaharchuk, Greg, Villringer, Arno, Villringer, Kersten, Gauthier, Claudine J
Format: Article
Language:English
Subjects:
Aged
Aged, 80 and over
Disease Susceptibility
Female
Humans
Hypoxia, Brain - blood
Hypoxia, Brain - diagnostic imaging
Longitudinal Studies
Magnetic Resonance Imaging
Male
Middle Aged
Original
Oxygen - blood
Perfusion
Stroke - blood
Stroke - diagnostic imaging
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Summary:Recent clinical trials of new revascularization therapies in acute ischemic stroke have highlighted the importance of physiological imaging to identify optimal treatments for patients. Oxygen extraction fraction (OEF) is a hallmark of at-risk tissue in stroke, and can be quantified from the susceptibility effect of deoxyhemoglobin molecules in venous blood on MRI phase scans. We measured OEF within cerebral veins using advanced quantitative susceptibility mapping (QSM) MRI reconstructions in 20 acute stroke patients. Absolute OEF was elevated in the affected (29.3 ± 3.4%) versus the contralateral hemisphere (25.5 ± 3.1%) of patients with large diffusion–perfusion lesion mismatch (P = 0.032). In these patients, OEF negatively correlated with relative CBF measured by dynamic susceptibility contrast MRI (P = 0.004), suggesting compensation for reduced flow. Patients with perfusion–diffusion match or no hypo-perfusion showed less OEF difference between hemispheres. Nine patients received longitudinal assessment and showed OEF ratio (affected to contralateral) of 1.2 ± 0.1 at baseline that normalized (decreased) to 1.0 ± 0.1 at follow-up three days later (P = 0.03). Our feasibility study demonstrates that QSM MRI can non-invasively quantify OEF in stroke patients, relates to perfusion status, and is sensitive to OEF changes over time. Clinical trial registration: Longitudinal MRI examinations of patients with brain ischemia and blood brain barrier permeability; clinicaltrials.org: NCT02077582
ISSN:0271-678X
1559-7016
DOI:10.1177/0271678X19827944