Pathogenic Heterogeneity of Distal Single Small Subcortical Lenticulostriate Infarctions Based on Lesion Size

Single small subcortical infarctions (SSSIs) in the lenticulostriate artery territory can be classified as proximal single small subcortical infarction (pSSSI) or distal single small subcortical infarction (dSSSI) lesions depending on the involvement of the lowest part of the basal ganglia. It was reported that pSSSI lesions have more characteristics of large artery atherosclerosis, whereas dSSSI lesions are more characteristic of small vessel disease. Because infarction of small vessels is more likely to be distal and may result in small lesions, we hypothesized that the clinical features of dSSSI lesions might be heterogeneous and classified based on lesion size.

Lenticulostriate SSSI patients admitted within 72 hours of stroke onset were included from a prospectively registered hospital-based stroke database. We determined the location (lowest slice [LS] involved) and size (total number of slices [TNS] involved) of SSSIs on magnetic resonance imagings. Based on lesion location, SSSIs were divided into pSSSI (LS ≤ 2) and dSSSI (LS > 2); the latter were further subdivided into distal and small SSSI (ds-SSSI, TNS ≤ 2) or distal and large SSSI (dl-SSSI, TNS > 2). The clinical characteristics were compared between different groups.

A total of 204 patients were included out of 1158 patients registered in the database. We found that ds-SSSI was most often associated with severe white matter hyperintensities. However, patients with dl-SSSI most often had a higher rate of additional concurrent atherosclerotic disease as coronary heart disease, compared to patients with ds-SSSI.

The pathogenesis of dSSSI may be heterogeneous depending on lesion size.