Incidence, Locations, and Longitudinal Course of Silent Microbleeds in Moyamoya Disease

Abstract

Background and Purpose—: Clinical significance of silent microbleeds is unknown in moyamoya disease. This study was aimed to clarify the incidence, locations, and longitudinal course. Methods—: This prospective cohort study included 78 nontreated patients with moyamoya disease. The incidence and locations of silent microbleeds were evaluated on T2*-weighted MRI. MR examinations were repeated every 6 or 12 months during a mean follow-up period of 43.1 months. Results—: T2*-weighted MRI identified silent microbleeds in 17 (29.3%) of 58 adult patients with moyamoya disease, but in none of 20 pediatric patients. During follow-up periods, de novo silent microbleeds developed in 4 (6.9%) of 58 adult patients. Hemorrhagic stroke occurred in 4 patients (6.9%), all of who had silent microbleeds on initial examination. The presence of silent microbleeds was a significant predictor for subsequent hemorrhagic stroke in adult moyamoya disease ( P <0.001). Conclusions—: Careful and long-term follow-up of silent microbleeds would be essential to improve their outcome in adult patients with moyamoya disease.