ABSTRACT NUMBER: ESOC2026A1913 INTRAPLAQUE HEMORRHAGE ON ROUTINE CAROTID MRI AFTER ACUTE ISCHAEMIC STROKE: INTERRATER AGREEMENT AND CLINICAL UTILITY

Abstract Background and aims Intraplaque hemorrhage (IPH) marks high-risk stroke patients and may guide inclusion or stratification in secondary prevention trials. We evaluated whether a simple non-contrast carotid MRI sequence, implemented as part of the routine diagnostic workup of acute stroke patients, enables reliable detection of IPH and provides clinical utility. Methods We analyzed consecutive patients admitted to a tertiary stroke center after implementation of carotid plaque MRI (3D, fat-saturated, T1-weighted sequence) into routine diagnostics. Pre-specified analyses included interrater agreement for IPH stratified for field strength and scanner type; prevalence of IPH ipsilateral vs. contralateral to brain infarction in patients with unilateral anterior circulation stroke of cryptogenic origin (primary analysis), and corresponding analyses for patients with acute ischaemic cerebrovascular events (ischaemic stroke, transient ischaemic attack, central retinal artery occlusion, or amaurosis fugax). Results Between 06/2020 and 03/2025, carotid plaque MRI data from 1,386 patients were available for analysis. Interrater agreement for IPH was high for scans obtained at 3 T (Gwet’s AC1 = 0.87 [95%CI:0.85-0.89]) and 1.5 T (Gwet’s AC1 = 0.83 [95%CI:0.80-0.86]). IPH was significantly more frequent ipsilateral vs. contralateral to brain infarction in patients with cryptogenic stroke (OR 9.00 [95%CI:1.14-71.04], P = 0.019) and in those with acute ischaemic cerebrovascular events (OR 4.44 [95%CI:2.16-9.16], P < 0.001). Presence of IPH reclassified stroke etiology in 5.9% of patients with unilateral anterior circulation stroke. Conclusions Routine non-contrast carotid MRI reliably detects IPH and enhances the diagnostic workup of stroke patients. These results support secondary stroke prevention trials that include or stratify patients based on the presence of IPH. Conflict of interest The authors have nothing to disclose relevant to the contents of this abstract. Figure 1 - belongs to Conclusions