EXPRESS: Following the curvature: sulcal versus gyral cortical localization of cerebral microbleeds in Cerebral Amyloid Angiopathy.

Cerebrospinal fluid (CSF) mediated brain clearance and inflammation are known features of Cerebral Amyloid Angiopathy (CAA), that may be affected by the cortical gyrencephalic structure. Considering these processes in the development of cerebral microbleeds (CMB), we compared sulcal and gyral cortical CMBs in sporadic and Dutch-type hereditary CAA (sCAA and D-CAA).CMBs were manually annotated on 3 Tesla (3T) susceptibility weighted imaging. Sulcal and gyral cortex-maps were created using FreeSurfer's curvature analysis of 3T T1-weighted scans. Sulcal and gyral CMB densities were compared using a generalized mixed linear model. Sensitivity analyses examined the influence of disease type and mixed pathology (presence of deep CMBs) on regional effect.The study included 28 participants (17/11 sCAA/D-CAA, mean age 70/53 years, and 54%/73% female, respectively). Sulcal CMB density was higher than gyral CMB density (B=0.618, exp(B)=1.86, p<0.001). Sensitivity analyses showed sulcal CMB predominance also when taking disease type into account (B=0.499, exp(B)=1.65, p=0.019), with higher CMB densities in sCAA (B=1.326, exp(B)=3.77, p=0.033) and robust sulcal CMB predominance when analyzing only participants with strictly cortical CMBs (B=0.583, exp(B)=1.79, p<0.001).Increased sulcal CMB density in CAA may indicate varying hemorrhagic vulnerability along the cortex, potentially arising from anatomy-based variations in inflammation and CSF flow dynamics.