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Updated: Mar 15, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Prediction of Stroke Onset Is Improved by Relative Fluid-Attenuated Inversion Recovery and Perfusion Imaging Compared
Anke Wouters1, Patrick Dupont2, Bo Norrving2
1From the Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven-University of Leuven, B-3000 Leuven, Belgium (A.W., R. Lemmens); VIB, Vesalius Research Center, Laboratory of Neurobiology, B-3000 Leuven, Belgium (A.W., R. Lemmens); Department of Neurology, University Hospitals Leuven, B-3000 Leuven, Belgium (A.W., R. Lemmens); Laboratory for Cognitive Neurology, KU Leuven, Herestraat 49, 3000 Leuven, Belgium (P.D.); Department of Clinical Sciences, Section of Neurology, Lund University, Sweden (B.N.); Guided Development GmbH, Heidelberg, Germany (R. Laage); Universitätsklinikum Hamburg-Eppendorf, Klinik und Poliklinik für Neurologie, Kopf-und Neurozentrum, Hamburg, Germany (G.T.); Stroke Center, Stanford University, Palo Alto, CA (G.W.A.); and Department of Neurology Austin Health, and Melbourne Brain Center, Florey Institute of Neuroscience and Mental Health, Heidelberg, Australia (V.T.). anke.wouters@med.kuleuven.be.
Background And Purpose:
Acute stroke patients with unknown time of symptom onset are ineligible for thrombolysis. The diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) mismatch is a reasonable predictor of stroke within 4.5 hours of symptom onset, and its clinical usefulness in selecting patients for thrombolysis is currently being investigated. The accuracy of the visual mismatch rating is moderate, and we hypothesized that the predictive value of stroke onset within 4.5 hours could be improved by including various clinical and imaging parameters.
Methods:
In this study, 141 patients in whom magnetic resonance imaging was obtained within 9 hours after symptom onset were included. Relative FLAIR signal intensity was calculated in the region of nonreperfused core. Mean Tmax was calculated in the total region with Tmax >6 s. Mean relative FLAIR, mean Tmax, lesion volume with Tmax >6 s, age, site of arterial stenosis, core volume, and location of infarct were analyzed by logistic regression to predict stroke onset time before or after 4.5 hours.
Results:
Receiver-operating characteristic curve analysis revealed an area under the curve of 0.68 (95% confidence interval 0.59-0.78) for the visual diffusion-weighted imaging/FLAIR mismatch, thereby correctly classifying 69% of patients with an onset time before or after 4.5 hours. Age, relative FLAIR, and Tmax increased the accuracy significantly (P<0.01) to an area under the curve of 0.82 (95% confidence interval 0.74-0.89). This new predictive model correctly categorized 77% of patients according to stroke onset before versus after 4.5 hours.
Conclusions:
In patients with unknown stroke onset, the accuracy of predicting time from symptom onset within 4.5 hours is improved by obtaining relative FLAIR and perfusion imaging.
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