The Effects of DWI-Infarct Lesion Volume on DWI-FLAIR Mismatch: Is There a Need for Size Stratification?

Seyedmehdi Payabvash, Shayandokht Taleb, John C. Benson, Jeffrey B. Rykken, Mark C. Oswood, Alexander M. McKinney, Benjamin Hoffman

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


BACKGROUND: The lack of fluid-attenuated inversion-recovery (FLAIR) hyperintensity in areas of diffusion-weighted imaging (DWI) high signal, or DWI-FLAIR mismatch, is a potential imaging biomarker for timing of stroke onset. We aimed to determine the effects of DWI infarct lesion volume on DWI-FLAIR mismatch and its accuracy for identification of strokes within intravenous (IV) the thrombolytic therapy window. METHODS: Acute ischemic stroke patients with magnetic resonance imaging scan within 12 hours of witnessed stroke were included. Two neuroradiologists independently reviewed DWI and FLAIR sequences for DWI-FLAIR mismatch in areas of restricted diffusion compared to the contralateral normal side. RESULTS: DWI-FLAIR mismatch was identified in 21/82 (26%) patients. Infarct lesions with DWI-FLAIR mismatch were scanned earlier (3.8 ±.3 vs. 7.5 ±.3 hours from onset, P <.001) and were smaller in size (8.9±2.3 vs. 43.1±11.9 mL, P =.007) compared to lesions without mismatch. Multivariate regression analysis showed a significant interaction between lesion volume and time-from-onset in relationship with the presence of DWI-FLAIR mismatch (P =.045). The presence of DWI-FLAIR mismatch had 56% sensitivity, 83% specificity, 48% positive predictive value (PPV), and 87% negative predictive value (NPV) for identification of infarction within 4.5 hours of symptom onset; while for infarct lesions >15 mL, the DWI-FLAIR mismatch had 100% specificity and PPV for acute infarcts within 4.5 hours of onset. CONCLUSION: The effects of stroke onset-to-scan time gap on DWI-FLAIR mismatch are not the same for different DWI lesion volumes. At DWI lesion volumes >15 mL, the DWI-FLAIR mismatch is highly specific for acute infarcts within IV thrombolytic therapy time, and can identify wake-up stroke patients eligible for treatment.

Original languageEnglish (US)
Pages (from-to)392-396
Number of pages5
JournalJournal of Neuroimaging
Issue number4
StatePublished - Jul 1 2017

Bibliographical note

Publisher Copyright:
Copyright © 2016 by the American Society of Neuroimaging


  • Ischemic stroke
  • diffusion-weighted imaging
  • fluid-attenuated inversion recovery
  • thrombolytic therapy
  • wake-up stroke


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