ABSTRACT NUMBER: ESOC2026A333 DISTINCT LOCATION PATTERNS OF SYMPTOMATIC RECENT SMALL SUBCORTICAL INFARCTS AND ‘SILENT’ LACUNES

Abstract Background and aims Recent small subcortical infarcts (RSSI) and lacunes are imaging markers of cerebral small vessel disease but differ in clinical presentation: RSSI, by definition, present with acute stroke symptoms, whereas lacunes often cannot be linked to prior symptoms. Previous work suggested this contrast may relate to lesion location. We investigated whether lesion locations differ between RSSI and lacunes in a large multicenter sample of patients with acute ischemic stroke. Methods Individual patient data from nine cohorts were harmonized through the Meta VCI Map consortium (www.metavcimap.org). Patients had symptomatic acute ischemic stroke, (sub)acute phase MRI (<6 weeks) and a visible acute infarct. Two subsamples were defined according to STRIVE-2 criteria: RSSI on DWI/FLAIR, and lacunes on FLAIR irrespective of acute infarct type (i.e. patients with RSSI may also have lacunes). Patients with prior stroke/TIA were excluded from the lacune group. RSSI and lacunes were manually delineated, registered to MNI-152 space, and compared using lesion prevalence maps. Results Among 1969 patients, 789 (40%) had RSSI and 613 (31%) had lacunes without prior stroke/TIA. RSSI showed a confined distribution covering the primary motor and somatosensory tracts (Figure 1). In contrast, lacunes were widely distributed across the semioval center, basal ganglia, thalamus and pons, with relative sparing of the internal capsule. Conclusions Patients with RSSI may present with acute neurological symptoms because of selective involvement of motor and sensory pathways, whereas lacunes commonly affect other locations. This highlights lesion location as a key determinant of symptomatic versus covert cerebral small vessel disease. Conflict of interest Nick A. Weaver: supported by Dekker Clinical Scientist grant 3-005-2024-0111 from Dutch Heart Foundation. Geert Jan Biessels: supported by Vici Grant 918.16.616 from ZonMW. Francesca M. Chappell, Maria del C. Valdés-Hernandez, and Joanna M. Wardlaw: nothing to disclose. Figure 1 - belongs to Results