Objective:To evaluate the utility of CT perfusion (CTP) for assessment of effect of encephalo-duro-arterio-synangiosis (EDAS) on moyamoya disease (MMD).Methods:Thirty-eight adult MMD patients, who underwent EDAS in our hospital from March 2014 to October 2019, were chosen in our study. All patients received CTP and digital subtraction angiography (DSA) before and after surgery; cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) in the operative cerebral cortices and their contralateral mirror areas, as well as brainstems were measured respectively; their relative parameter values (rCBF, rCBV, rMTT and rTTP) were calculated with the brainstem as the reference; perfusion changes of cerebral tissues were observed before and after surgery, and efficacies of these parameters in evaluating the surgical treatment effect were compared. According to the degrees of collateral formation detected by postoperative DSA, the 42 hemispheres of these patients were divided into group of good collateral formation and group of poor collateral formation, and the differences of perfusion changes in the two groups were further discussed.Results:CTP revealed that cerebral perfusion at surgical side after EDAS was significantly improved in all the 42 hemispheres; significantly increased rCBF, and significantly decreased rMTT and rTTP were noted as compared with those before surgery ( P<0.05). Receiver operating characteristic (ROC) curve showed that the area under the curve of rTTP (0.897) was the largest among all parameters, with diagnostic sensitivity of 87.5% and specificity of 80.8%. Twenty-six patients (61.9%) were into the group of good collateral formation and 16 (38.1%) were into the group of poor collateral formation; changed values of rCBF and rMTT in the group of good collateral formation were significantly better than those in the group of poor collateral formation ( P<0.05). Conclusion:CTP can quantitatively evaluate cerebral hemodynamic changes after EDAS in moyamoya disease patients, and postoperative rTTP changes can reflect the degrees of collateral vessel formation.