OBJECTIVE: To examine the relationship between asymptomatic microbleeds (MBs) and the occurrence of subsequent stroke in patients with moyamoya disease. METHODS: Beginning in October 2003, 50 consecutive patients with moyamoya disease were enrolled in a prospective study using 3-T magnetic resonance imaging. These patients were followed from the date of the initial magnetic resonance study until the date of the first subsequent stroke or final magnetic resonance study. The median follow-up period was 15 months. The patients were comprised of 13 men and 37 women ranging in age from 9 to 68 years (mean age, 40.5 +/- 16.2 yr). RESULTS: Although no MBs were found in 27 patients in the initial magnetic resonance study, a total of 66 MBs were found in the remaining 23 patients. Eleven patients had a single MB and 12 had multiple MBs. The patients were divided into three groups according to the number of MBs: a non-MB group, a single-MB group, and a multi-MB group. Kaplan-Meier curves of the three groups showed a significantly higher likelihood of subsequent hemorrhage in the multi-MB group than in either the non-MB or single-MB groups (P = 0.0380). No significant differences among the three groups were seen in terms of their subsequent infarction-free ratios. Age-adjusted analysis performed with the Cox proportional hazard model also showed the presence of multiple MBs as an independent risk factor (hazard ratio, 2.89; 95% confidence interval, 1.001-13.24). CONCLUSION: The presence of multiple MBs might be a predictor of subsequent hemorrhage in patients with moyamoya disease. Confirmation of these results will require a study with a larger number of patients and a longer follow-up period.
OBJECTIVE: To examine the relationship between asymptomatic microbleeds (MBs) and the occurrence of subsequent stroke in patients with moyamoya disease. METHODS: Beginning in October 2003, 50 consecutive patients with moyamoya disease were enrolled in a prospective study using 3-T magnetic resonance imaging. These patients were followed from the date of the initial magnetic resonance study until the date of the first subsequent stroke or final magnetic resonance study. The median follow-up period was 15 months. The patients were comprised of 13 men and 37 women ranging in age from 9 to 68 years (mean age, 40.5 +/- 16.2 yr). RESULTS: Although no MBs were found in 27 patients in the initial magnetic resonance study, a total of 66 MBs were found in the remaining 23 patients. Eleven patients had a single MB and 12 had multiple MBs. The patients were divided into three groups according to the number of MBs: a non-MB group, a single-MB group, and a multi-MB group. Kaplan-Meier curves of the three groups showed a significantly higher likelihood of subsequent hemorrhage in the multi-MB group than in either the non-MB or single-MB groups (P = 0.0380). No significant differences among the three groups were seen in terms of their subsequent infarction-free ratios. Age-adjusted analysis performed with the Cox proportional hazard model also showed the presence of multiple MBs as an independent risk factor (hazard ratio, 2.89; 95% confidence interval, 1.001-13.24). CONCLUSION: The presence of multiple MBs might be a predictor of subsequent hemorrhage in patients with moyamoya disease. Confirmation of these results will require a study with a larger number of patients and a longer follow-up period.