Fluid-Attenuated Inversion Recovery (FLAIR) Signal Intensity Can Identify Stroke Within 6 and 8 Hours.
BACKGROUND
Patients with wake-up or unknown time of onset stroke are usually excluded from recanalization. However, a few studies indicate that some magnetic resonance sequences can help predict time from symptom onset (SxO). Our goal was to assess the value of fluid-attenuated inversion recovery (FLAIR) signal intensity ratio (SIR) in identifying patients within 6 and 8 hours of stroke onset.


MATERIALS AND METHODS
We studied consecutive acute stroke patients with known time of onset who underwent magnetic resonance imaging (MRI) within 48 hours of SxO. SIR was calculated as the value of the FLAIR signal intensity of the identified area of infarction divided by the signal intensity in the homologous contralateral side of the brain.


RESULTS
Out of 160 patients included in this study, 72 and 80 patients had MRI within 6 and 8 hours of SxO, respectively. We found a positive correlation between SIR and time from SxO (Pearson coefficient, .63). Receiver operating characteristic curves indicated that SIR ≤ 1.18 could accurately identify patients within 6 hours of SxO (86% sensitivity, 79% specificity) and a SIR ≤ 1.20 can be identified within 8 hours (89% sensitivity, 76% specificity). Among patients with no visible FLAIR hyperintensity, 83% (95% CI, 77%-89%) were within the 6-hour window.


CONCLUSION
Quantitative assessment of FLAIR sequence can be used to identify patients within 6 and 8 hours of stroke onset.
['Legge|John|J|', 'Graham|Ada|A|', 'Male|Shailesh|S|', 'Copeland|David|D|', 'Lee|Richard|R|', 'Goyal|Nitin|N|', 'Zand|Ramin|R|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D019540:Area Under Curve D038524:Diffusion Magnetic Resonance Imaging D005260:Female D006801:Humans D007090:Image Interpretation, Computer-Assisted D008297:Male D008875:Middle Aged D011237:Predictive Value of Tests D012372:ROC Curve D015203:Reproducibility of Results D020521:Stroke D061665:Time-to-Treatment
stroke onset acute stroke MRI Brain imaging DWI ischemic stroke thrombectomy thrombolysis