Heterogeneity of single small subcortical infarction can be reflected in lesion location

Single small subcortical infarction (SSSI), also called lacunar infarction, has been regarded as a different entity with distinct pathogenesis, either lipohyalinosis and fibrinoid degeneration or atherosclerosis. The aim of our study is to identify the heterogeneity of SSSI by comparing the characteristics and imaging features according to lesion location. We retrospectively studied 203 patients with acute SSSIs (diameter ≤20 mm) demonstrated by diffusion-weighted imaging in the perforator territory of the middle cerebral artery, basilar artery, or vertebral artery. We divided the 203 patients according to the lesion location in relation to the parent artery into a distal infarction (dSSSI) group and a proximal infarction (pSSSI) group. We evaluated and compared the imaging features and clinical characteristics between the groups. The evaluated characteristics included indicators of lipohyalinosis [leukoaraiosis and silent brain infarction (SBI)], indicators of atherosclerosis [parent artery disease (PAD) and atherosclerosis of other cerebral arteries (AOCA)], lesion size, and some vascular risk factors. Between the two groups, the pSSSI group had larger lesion size, higher prevalence of PAD and AOCA, and greater frequency of diabetes mellitus, while the dSSSI group had smaller lesion size, higher prevalence of leukoaraiosis and SBI, and lower serum folic acid. Diversity of the SSSIs in imaging features and clinical characteristics according to lesion location suggests the heterogeneity of SSSIs; distal infarction is closely associated with lipohyalinosis, while proximal infarction seems to be related with atherosclerosis.