ABSTRACT NUMBER: ESOC2026A1566 DIAGNOSTIC PERFORMANCE OF ULTRAFAST BRAIN MRI EXAMINATION (EPIMIX) FOR SUSPECTED MINOR ISCHEMIC STROKE AND MANIFESTATIONS OF SMALL VESSEL DISEASE

Abstract Background and aims Fast magnetic resonance imaging (MRI) sequences have shown potential for accurate diagnosis and improved patient tolerability in stroke evaluation. This study aimed to compare ultra-fast echo-planar image mix (EPIMix) with conventional MRI as gold standard (GS) in diagnosing suspected minor stroke. Methods In this prospective study, 101 persons with suspected stroke and negative brain computed tomography (CT) were examined with GS (acquisition time eleven minutes) and EPIMix (78 seconds) at 3 Tesla, including multiple weightings (T2, T2 Fluid-Attenuated Inversion Recovery [FLAIR], T1-FLAIR, diffusion [DWI], T2*). One neuroradiologist and one radiology resident independently evaluated images for acute infarcts, white matter hyperintensities (WMH) and cerebral microbleeds (CMB). Sensitivity and specificity were calculated for EPIMix compared to GS and interrater reliability using weighted Cohen’s kappa for diagnostic confidence quality. Results Thirty-four patients were diagnosed with ischemic stroke; mean National Institutes of Health Stroke Scale scores at inclusion were 1 (IQR 0-3). Diffusion restriction was detected in 28 persons when examined with GS vs 23 with EPIMix (sensitivity 0.82, specificity 1.00). Moderate to severe WMH (Fazekas scale grade 2-3) was seen in 41 vs 40 persons (sensitivity 0.88, specificity 0.93) and CMB in 26 vs 19 persons (sensitivity 0.58, specificity 0.94). Inter-rater reliability was greater for EPIMix (k=0.72) than GS (k=0.62). Conclusions In persons with minor stroke and negative brain CT, EPIMix had a good, but not perfect ability to detect ischemia. The high specificity allows for ruling in ischemia, but not for ruling out. EPIMix also had good specificity for detecting WMH and CMB. Conflict of interest Oskar Koivisto Taxén: nothing to disclose. Ida Gugler: nothing to disclose. Jenny Bäcklund: nothing to disclose. Tommy Sjöberg: nothing to disclose. Tobias Granberg: nothing to disclose. Anders von Heijne: nothing to disclose. Björn Hansen: nothing to disclose. Annika Lundström: nothing to disclose.