To investigate the clinical and imaging characteristics of symptomatic acute subcortical cerebral microinfarcts (AS-CMI) in elderly patients with cerebral small vessel disease (CSVD).

A total of 240 patients with recent small subcortical infarcts (RSSI) hospitalized in the Department of Neurology of Zhongguancun Hospital, Beijing from September 2019 to February 2025 were retrospectively enrolled. Based on lesion diameter, patients were divided into the ASCMI group (diameter < 5 mm; n=19) and the larger RSSI group (diameter 5 – 20 mm; n=221). Clinical data [including National Institutes of Health stroke scale (NIHSS), MiniMental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA) scores] and brain magnetic resonance imaging features [such as white matter hyperintensity (WMH), lacunes, and perivascular spaces] were collected. Univariate analyses (t-test, Wilcoxon ranksum test, and χ² test) were used to compare differences between the two groups. Multiple binary Logistic regression was performed to identify independent risk factors for ASCMI.

Compared with the larger RSSI group, the ASCMI group had significantly lower MMSE scores [24 (20, 26) vs 26 (23, 28); Z=2.226, P=0.026] and MoCA scores [16 (13, 22) vs 20 (15, 23); Z=2.105, P=0.035]. Moreover, the ASCMI group showed higher periventricular WMH [2 (1, 3) vs 1 (0, 2); Z=2.288, P=0.022], deep WMH [1 (1, 3) vs 1 (0, 2); Z=2.249, P=0.025], proportions of lacunes (73.6% vs 43.0%; χ²=6.651, P=0.010) and cerebral microbleeds (36.8% vs 17.6%; χ²=4.161, P=0.042), as well as a higher total CSVD burden score [2 (1, 3) vs 1 (1, 2); Z=4.037, P<0.001]. Multiple binary Logistic regression revealed that the total CSVD burden score was an independent risk factor for AS-CMI (OR=4.441, 95%CI: 1.446 - 13.645, P=0.009).

Patients with ASCMI had more severe cognitive impairment and a higher total CSVD burden. Despite their small size, ASCMI lesions were associated with noticeable neurological deficits and did not show better functional outcomes.