Diversity of Single Small Subcortical Infarctions According to Infarct Location and Parent Artery Disease

Single small subcortical infarctions (SSSIs), so-called lacunae, are typically caused by lipohyalinosis of a perforator artery. However, SSSIs can be caused by underlying large parent arterial disease or microatheroma of the proximal portion of a perforator artery. We sought to investigate whether indicators for small vessel disease (SVD) and atherosclerosis in patients with SSSI differ according to lesion location and the presence of parent artery disease.We assessed 449 patients who had an SSSI (lesion diameter ≤ 20 mm) in the perforator territory of middle cerebral artery (n = 244), basilar artery (n= 141), and vertebral artery (n = 64) on diffusion-weighted imaging performed within 48 hours of stroke onset. We divided SSSI into 3 groups according to lesion location and the presence of parent artery disease: (1) SSSI with parent artery disease (SSSI+PAD); (2) proximal SSSI without PAD (pSSSI-PAD); and (3) distal SSSI without PAD (dSSSI-PAD). The prevalence of SVD indicators (leukoaraiosis and microbleeds) and atherosclerosis indicators (cerebral atherosclerosis and coronary heart disease) were compared among the groups.SSSI+PAD had the highest prevalence of atherosclerosis indicators and the lowest prevalence of SVD indicators, whereas dSSSI-PAD had the lowest prevalence of atherosclerosis indicators and the highest prevalence of SVD indicators. pSSSI-PAD showed intermediate features. Atherosclerosis indicators significantly increased and SVD indicators significantly decreased as the vascular territory became lower (from middle cerebral artery, basilar artery to vertebral artery).Differences in SVD and atherosclerosis indicators suggest that SSSI has a heterogeneous pathogenesis according to lesion location and the presence of PAD.