ABSTRACT NUMBER: ESOC2026A2163 CLINICAL UTILITY OF INTRACRANIAL VESSEL WALL MRI ON ETIOLOGY DETERMINATION OF ISCHEMIC STROKE IN YOUNG ADULTS – A PROSPECTIVE COHORT STUDY

Abstract Background and aims In young adults with ischemic stroke, standard-of-care workup frequently fails to identify the stroke etiology. We aimed to assess the utility of intracranial vessel wall MRI (VW-MRI) on etiologic diagnosis in these patients. Methods Between 2014-2019, we prospectively recruited consecutive adult ischemic stroke patients under age 60 for 3-Tesla VW-MRI added to standard-of-care etiologic workup. An expert panel reviewed standard-of-care investigations to determine stroke etiology, followed by VW-MRI to conclude whether this altered stroke etiology. We assessed the proportion of patients with changed etiology after VW-MRI and identified predictors for altered etiology through logistic regression analysis. In the absence of a gold standard, we contacted participants in 2025 to determine the recurrent stroke incidence and revised stroke etiology over time. Results We included 102 patients, 44 women (43%), median age 48 (IQR 42-54). Stroke etiology on standard-of-care workup was changed after reviewing VW-MRI in 36/102 patients (35%, 95%CI27-45%). Nonspecific intracranial arteriopathy (OR17.7, 95%CI 4.3-73.2), cryptogenic stroke (OR24.6, 95%CI 2.7-225.4), and multiple etiologies on standard workup (OR20.5, 95%CI 2.2-193.3) were independently associated with altered diagnosis after VW-MRI. 9/102 participants (9%) had recurrent stroke during a median follow-up of 8.7 years (IQR 7.3-9.9). None of them had a revised stroke etiology. In six patients, an alternative stroke etiology was identified unrelated to the index stroke. Conclusions Intracranial VW-MRI resulted in sustainable etiology modification in a third of young stroke patients, particularly when stroke etiology was unclear or an intracranial arteriopathy was suspected. VW-MRI should therefore be considered in these situations. Conflict of interest Joanna Schaafsma: Nothing to disclose. Josephine Duijster: Nothing to disclose. Frank Silver: Nothing to disclose. Sapna Rawal: Nothing to disclose. Helena Janssen: Nothing to disclose. David Mikulis: Nothing to disclose. Danny Mandell: Nothing to disclose.