Meandering flow void around the splenium in moyamoya disease.

Objectives: Meandering flow void around the splenium, which can be recognized on conventional T2-weighted images, implicates collateral flow in the splenial artery in patients with moyamoya disease. In this report, curves of flow voids around the splenium (SFVs) were evaluated in patients with moyamoya disease, and their diagnostic value and pathophysiology were verified. Methods: A total of 65 consecutive patients with moyamoya disease were included in this analysis. The number of SFV curves was counted on each side. The numbers of SFV curves in patients with moyamoya disease was compared with those in the control group. The clinical features of patients with large numbers of flow voids were analyzed. Results: The mean number of SFVs was significantly higher in the moyamoya disease group than in the control group or the atherosclerotic disease group. The cut-off SFV count for a diagnosis of moyamoya disease should be set to 2.25 in consideration of receiver operating characteristic curve analysis. A multivariate logistic analysis of SFV data in moyamoya disease revealed significant differences between the high SFV count group (2.25) and the low SFV count group (<2.25) in age, flow voids in the basal ganglia, and magnetic resonance angiography score of the internal carotid artery and anterior cerebral artery. Conclusion: Based on this study, number of SFV curves on conventional T2-weighted imaging could be a useful measurement for confirming a diagnosis of moyamoya disease. Increased number of SFV curves was associated with age and progress of disease.