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Updated: May 11, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Can diffusion-weighted imaging-fluid-attenuated inversion recovery mismatch (positive diffusion-weighted
Samuel Emeriau1, Isabelle Serre, Olivier Toubas
1Department of Neuroradiology, Hôpital Maison-Blanche, CHU de Reims, 45, rue Cognacq-Jay, 51092 Reims cedex, France.
Background And Purpose:
At 1.5 T, diffusion-weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch helps identify strokes within 4.5 hours of onset. However, at 3T, studies have found divergent results. The goal of this study was to determine whether DWI-FLAIR mismatch at 3T would also be helpful for identifying patients within 4.5 hours of symptom onset.
Methods:
All patients presenting with an ischemic stroke in the middle cerebral artery territory and explored with 3T MRI within 12 hours between November 2007 and April 2012 were included in this retrospective study. Two readers analyzed the DWI and FLAIR images. Logistic regression was performed to determine independent predictors of FLAIR visibility. Also, the predictive values of a mismatch for identifying patients with stroke onset ≤4.5 hours were estimated.
Results:
The study included 194 patients. The only predictive factor of FLAIR visibility was delayed MRI acquisition. The DWI-FLAIR mismatch was able to identify patients within 4.5 hours of stroke onset with relatively low sensitivity (0.55; 95% confidence interval, 0.48-0.63), low specificity (0.60; 95% confidence interval, 0.42-0.77), high positive predictive value (0.88; 95% confidence interval, 0.82-0.94), and very low negative predictive value (0.19; 95% confidence interval, 0.11-0.28). In addition, 44.5% of patients had a positive FLAIR sequence within 4.5 hours.
Conclusions:
This study improves our understanding of DWI-FLAIR mismatch as an imaging biomarker for wake-up management of patients with stroke. At 3T, the presence of a DWI-FLAIR mismatch was able to identify stroke onset of <4.5 hours. However, 44.5% of such stroke cases demonstrated FLAIR signal changes.
Insights
Diffusion-weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch at 3T MRI shows potential for identifying early stroke. However, its low sensitivity and specificity suggest caution when using this biomarker for acute ischemic stroke management.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Diffusion-weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch is established for identifying early strokes at 1.5T MRI.
- Previous studies at 3T MRI have yielded conflicting results regarding the utility of DWI-FLAIR mismatch.
Purpose of the Study:
- To evaluate the effectiveness of DWI-FLAIR mismatch at 3T MRI for identifying ischemic stroke patients within 4.5 hours of symptom onset.
- To determine predictors of FLAIR visibility and assess the predictive values of DWI-FLAIR mismatch in this context.
Main Methods:
- Retrospective analysis of 194 ischemic stroke patients who underwent 3T MRI within 12 hours of symptom onset.
- Two readers assessed DWI and FLAIR images for mismatch.
- Logistic regression identified predictors of FLAIR visibility; predictive values for early stroke identification were calculated.
Main Results:
- Delayed MRI acquisition was the sole predictor of FLAIR visibility.
- DWI-FLAIR mismatch showed low sensitivity (0.55) and specificity (0.60) for identifying strokes within 4.5 hours.
- Positive predictive value was high (0.88), but negative predictive value was very low (0.19).
- FLAIR signal changes were present in 44.5% of patients within 4.5 hours of stroke onset.
Conclusions:
- DWI-FLAIR mismatch at 3T MRI can indicate stroke onset within 4.5 hours.
- The presence of FLAIR signal changes in nearly half of early stroke cases warrants consideration.
- Findings enhance understanding of DWI-FLAIR mismatch as a biomarker for wake-up stroke management.
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