Objective To observe the value of three-dimensional arterial spin labeling (3D-ASL) PWI in evaluating postoperative cerebral perfusion changes in patients with Moyamoya disease.Methods Totally 19 patients of Moyamoya disease confirmed with DSA were enrolled.All the patients received revascularization.Before and after operation,3D-ASL PWI and dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI) were performed.ROI was located in the region with obvious perfusion changes supplied by middle cerebral artery on the operating side.Then the cerebral blood flow (CBF) was measured on 3D-ASL images,and time to peak (TTP) was measured on DSC-PWI images before and after operation.The differences of CBF and TTP before and after operation were compared,as well as the improvement rate of CBF,TTP and clinical symptoms.Results Before and after operation,CBF was (41.40±11.36) ml/(100 g · min) and (54.10±16.69) ml/(100 g · min),respectively,and the difference was statistically significant (t=-4.273,P＜0.01).TTP was (28.66 ± 3.21) s and (26.44 ± 3.93) s,respectively,and the difference was also statistically significant (t =-2.936,P＜0.01).The improvement rate of clinical symptoms was 84.21％ (16/19),of CBF was 78.95％ (15/19) and of TTP was 68.42％ (13/19),the differences of improvement rate had no statistically significant (P=0.625).Conclusion 3D-ASL PWI is noninvasive,no contrast agent need to be used,and can be used to evaluate perfusion changes after operation of revascularization in patients with Moyamoya disease.