Increased extracellular free water content is associated with cerebral microbleed severity in patients with cerebral small vessel disease: A cross-sectional study

This study investigated the association between extracellular free water (FW) content and the severity of cerebral microbleeds (CMB) in patients with cerebral small vessel disease (CSVD). Clinical data and multimodal magnetic resonance imaging data from 159 patients with CSVD were analyzed. Diffusion tensor imaging was used to quantify FW, and CMB were assessed using susceptibility-weighted imaging. Participants were categorized into 3 groups according to CMB burden: no CMB, mild CMB (1–2), and extensive CMB (≥3). The mean FW value was 0.25 ± 0.02, and CMB were identified in 53 patients (33.3%). Spearman correlation analysis demonstrated a significant positive association between FW values and CMB burden ( R = 0.511, P < .001). FW, age, sex, hypertension, and white matter hyperintensity (WMH) volume differed significantly between the CMB groups ( P < .05). Multivariate linear regression analysis further confirmed that extracellular FW was independently associated with CMB severity after adjustment for age, hypertension, and WMH volume ( P < .05). These findings suggest that increased extracellular FW content is independently associated with both the presence and severity of CMB in patients with CSVD.