IsCHEMiA in Vascular Epilepsy: Identifying Risks for Post Stroke Epilepsy

Development and International Validation of a Novel Imaging-Based Risk Score (IsCHEMiA) for the Prediction of Poststroke Epilepsy Leung WCY, Tanaka T, Donahue RA, Chan KCW, Wang J, Chung THF, Wong YK, Liu KCR, Leung IYH, Ho RW, Chu FHN, Leung AKL, Teo KC, Pang SYY, Yip EK, Ihara M, Fukuma K, Reeder HT, Chibnik LB, Cole AJ, Lau GKK, Singhal AB. Neurology . 2026;106(2):e214486. Background and Objectives: Stroke is one of the most common causes of adult-onset epilepsy. We aimed to develop a model to predict poststroke epilepsy (PSE) after a first-ever ischemic stroke, incorporating neuroimaging features of incident stroke. Methods: We analyzed clinical and neuroimaging features of patients with first-ever acute ischemic stroke consecutively admitted to Massachusetts General Hospital, United States. We performed competing risk regression with all-cause mortality as a competing event and derived the final multivariable model using backward stepwise elimination by the Akaike Information Criterion. We externally validated the model in three international cohorts in Hong Kong (Queen Mary Hospital [HK-QMH], Ruttonjee Hospital [HK-RH]) and Japan (National Cerebral and Cardiovascular Center) by discrimination and calibration and compared its performance with the SeLECT and SeLECT2.0 scores. Results: We included a final derivative cohort of 1436 patients with a mean age of 67.4 years and a slight male predominance (54.7%), along with a total of 2534 patients in the validation cohorts. PSE, defined as the occurrence or recurrence of unprovoked seizure >7 days after stroke, occurred in 5.5% of the overall study population. Six variables (infarct size [Is], cortical involvement [C], hemorrhagic transformation [H], early seizures [E], MCA involvement [Mi], and age younger than 65 [A]) were independent predictors included in the final model and formed the IsCHEMiA score. Model discrimination was consistent across all cohorts, with c-statistics of 0.870 (United States), 0.852 (HKQMH), 0.857 (HK-RH), and 0.826 (Japan). The model was well calibrated at 1 and 3 years after stroke in the overall validation cohort. The IsCHEMiA score improved the prediction of PSE compared with SeLECT in all cohorts and the overall study population (c-statistic 0.848 vs 0.782, z = 5.170, P < .0001). For example, an IsCHEMiA score of 3 predicts a low risk of PSE at 1 year (2%) and 5 years (6%) while an IsCHEMiA score ≥8 predicts a high risk at 1 year (67%) and 5 years (78%). Discussion: The IsCHEMiA score is an improved and readily applicable predictive model developed and validated using international stroke cohorts in the modern era of reperfusion therapies. It serves as a foundation for personalized management and may guide future clinical trials on antiepileptogenic therapies in acute ischemic stroke.