Difficulty of MRI based identification of lesion age by acute infra-tentorial ischemic stroke.

Florian Grosse-Dresselhaus,Ivana Galinovic,Heinrich J Audebert,Jochen B Fiebach,Kersten Villringer

doi:10.1371/journal.pone.0092868

Florian Grosse-Dresselhaus, Ivana Galinovic + Show 3 more

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https://doi.org/10.1371/journal.pone.0092868

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Journal: PloS one	Publication Date: Mar 20, 2014
Citations: 11	License type: CC BY 4.0

Affiliation: Charité - Universitätsmedizin Berlin

Abstract

BackgroundSystemic thrombolysis in acute ischemic stroke is restricted to the 4.5 h time window. Many patients are excluded from this treatment because symptom onset is unknown. Magnetic resonance imaging (MRI) studies have shown that stroke patients presenting with acute supra-tentorial diffusion-weighted imaging (DWI) lesions that do not have matching lesions on fluid attenuated inversion recovery (FLAIR) are likely to be within a 4.5 hour time window. This study examines the DWI-FLAIR mismatch in infra-tentorial stroke.MethodsThis was a retrospectively conducted substudy of the “1000+” study; a prospective, single-center observational study (http://clinicaltrials.gov; NCT00715533). Fifty-six patients with infra-tentorial stroke confirmed by MRI and known symptom onset who underwent the scan within 24 h after symptom onset were analysed. Two neurologists blinded to clinical information separately rated the DWI lesion visibility on FLAIR. Lesion volume, relative signal intensities of DWI and relative apparent diffusion coefficient values were determined.ResultsRegarding baseline characteristics our study population had a median age of 66 years, a median time from symptom onset to MRI of 616.5 minutes, a median NIHSS of 3 and a median DWI lesion volume of 0.26 ml. A negative FLAIR allocated patients to a time window under 4.5 h correctly with a sensitivity of 55% and a specificity of 61%, a positive predictive value of 44% and a negative predictive value of 71%. FLAIR positivity decreased with age (p = 0.018), and showed no significant correlation to lesion volume (p = 0.145).ConclusionsIn our study the DWI-FLAIR-Mismatch does not help to reliably identify patients within 4.5 h of symptom onset in acute ischemic infra-tentorial stroke. Thus therapeutical decisions based on the DWI-FLAIR mismatch estimation of time from onset cannot be recommended in patients with infra-tentorial stroke.

Highlights

Systemic thrombolysis in acute ischemic stroke is restricted to the 4.5 h time window [1]
Most studies report a high predictive value of diffusion-weighted imaging (DWI)-fluid attenuated inversion recovery (FLAIR) mismatch to identify early stroke patients eligible for thrombolysis [3,4,5,6,7]. Based on these imaging findings patients with unknown symptom onset time might benefit from an emergency reperfusion therapy when showing a DWIFLAIR mismatch [5]
In a study by Aoki et al 50% of patients who were FLAIR negative past a 6-hour time window had an infra-tentorial lesion [7] hinting at a difference in signal behaviour between supra- and infra-tentorial stroke

Summary

Introduction

Systemic thrombolysis in acute ischemic stroke is restricted to the 4.5 h time window [1]. Most studies report a high predictive value of DWI-FLAIR mismatch to identify early stroke patients eligible for thrombolysis [3,4,5,6,7]. Based on these imaging findings patients with unknown symptom onset time might benefit from an emergency reperfusion therapy when showing a DWIFLAIR mismatch [5]. Magnetic resonance imaging (MRI) studies have shown that stroke patients presenting with acute supra-tentorial diffusion-weighted imaging (DWI) lesions that do not have matching lesions on fluid attenuated inversion recovery (FLAIR) are likely to be within a 4.5 hour time window. This study examines the DWI-FLAIR mismatch in infra-tentorial stroke

Methods

Results

Conclusion