Fluid-Attenuated Inversion Recovery Correlates with Stroke Onset in Childhood Arterial Ischemic Stroke

BACKGROUND AND PURPOSE: In adults, time since stroke onset correlates with safety and efficacy of recanalization therapies, and the appearance of FLAIR hyperintense signal is considered a proxy for time. The time to FLAIR hyperintensity in childhood stroke is unknown but is of interest because time of stroke onset in childhood stroke is often unknown. MATERIALS AND METHODS: Time to FLAIR hyperintensity on brain MRI performed on children within 24 hours of stroke onset was studied with Bayesian accelerated failure time models. RESULTS: A total of 82 MRIs with FLAIR imaging were available from 72 children (37 girls), median age of 10.9 years (range: 0.8-18.0 years). Seventy-two percent (52/72) of children had anterior circulation stroke. Median time between stroke onset and MRI was 7 hours (range: 0.5-23.5 hours). The median estimated time to FLAIR presence was 5.4 hours (50% Bayesian credible interval [BCI], 2.9-8.8; 90% BCI, 0.7-16.7) for all patients, and 6.0 hours (50% BCI, 4.4-7.3; 90% BCI, 1.9-8.8) for anterior circulation only strokes. For all patients, when no signal hyperintensity on FLAIR is observed, there is 50% chance the stroke occurred more than 5.4 hours ago and a 25% chance the stroke occurred more than 8.8 hours ago. For anterior circulation only strokes without FLAIR hyperintense signal, there is a 50% chance the stroke occurred more than 6.0 hours ago, and a 25% chance the stroke occurred more than 7.3 hours ago. CONCLUSIONS: FLAIR signal hyperintensity can be used to estimate time since stroke ictus in childhood stroke. Children may have a similar FLAIR signal change timing compared with adults, suggesting that they may have a similar window for effective recanalization therapies.