Abstract TP213: Diagnostic Score to Differentiate the Etiology of Cortical Microinfarcts on 3-Tesla MRI

Abstract

Background and Purpose: Cortical microinfarcts (CMIs) are small ischemic lesions found in cerebral amyloid angiopathy (CAA) patients, which are also associated with embolic stroke. This study aimed to differentiate cortical microinfarcts caused by CAA from those caused by microembolism, using 3-tesla magnetic resonance imaging. Methods: We retrospectively investigated 119 patients with at least 1 cortical infarct <10 mm on 3D double inversion recovery imaging. Forty-three patients with an embolic stroke history were included as the emboli group (Emboli-G) and 27 patients with CAA were included as the CAA group (CAA-G), based on the modified Boston criteria. We compared the size, number, location, and distribution of CMIs between groups to assess CMI etiology. Using this information, we designed a radiological diagnostic score, which incorporated data on the location, size, distribution, and numbers of CMIs. Results: CAA-G patients showed significantly more lesions <5 mm, which were restricted to the cortex (p<0.01). Cortical lesion number was significantly higher in Emboli-G than in CAA-G patients (4 vs 2; p<0.01). The diameter of cortical lesions was significantly larger in Emboli-G than in CAA-G patients (3.8 mm vs 3.0 mm; p<0.01). Lesions in CAA-G and Emboli-G patients were disproportionately located in the occipital lobe (p<0.01) and frontal or parietal lobe (p=0.04), respectively. In diagnostic scoring, a score of ≥3 points strongly predicted microembolism (sensitivity, 63%; specificity, 92%) or CAA (sensitivity, 63%; specificity, 91%). The area under the curve was 0.85 and 0.87 for microembolism and CAA, respectively. Conclusions: Our radiological diagnostic score may be a powerful tool for differentiating the etiology of CMIs.