Nascent lobar microbleeds and stroke recurrences.

BACKGROUND: Lobar microbleeds (MBs) are occasionally visible on gradient-echo T2*-weighted (T2*-w) magnetic resonance imagings (MRIs) in patients with deep intracerebral hemorrhages (ICHs). This study investigated the contribution of nascent lobar MBs to occurrences of deep ICHs.

METHODS: We prospectively analyzed nascent lobar MBs in patients admitted to our hospital who were treated with index strokes between April 2004 and November 2009. Numbers of nascent lobar MBs were counted on T2*-w MRI scans around 1 year after index strokes and compared with previous MRIs on admission. Deep ICH occurrence-free rate curves were generated by the Kaplan-Meier method using the log-rank test. The odds ratio (OR) for deep ICH occurrence was derived from a multivariate logistic regression model using nascent lobar MBs and risk factors.

RESULTS: We investigated MRIs (interscan interval: 14.6 ± 5.9 months) of 508 patients (207 women, 68.9 ± 11.5 years), with a follow-up period of 44.1 ± 15.4 months. Repeated T2*-w MRIs demonstrated 157 nascent lobar MBs in 62 of 508 patients. The occurrence rate of deep ICHs (1.9% per year) was significantly higher in patients with nascent lobar MBs than in those without (.5% per year, P = .012). Multivariate analyses revealed that the rate of nascent lobar MBs was significantly elevated in patients with deep ICH-type stroke recurrences (OR: 3.85, P = .020), adjusted by the presence of hypertension, diabetes mellitus, use of antithrombotic drugs, severity of white matter lesions, age, and gender.

CONCLUSIONS: Though a cohort study limited the power of analyses, our findings suggested that lobar MBs might be associated with deep ICH.