Moyamoya Disease: Evaluation of Postoperative Revascularization Using Multiphase Selective Arterial Spin Labeling MRI

Purpose: The purpose of this study was to evaluate cerebral blood flow through the bypass in operated patients with Moyamoya disease using multiphase selective arterial spin labeling (ASL) technique. Materials and Methods: Fifteen surgically treated cerebral hemispheres from 11 patients with Moyamoya disease were included. Selective ASL examinations were performed during the early postoperative period (mean, 5.5 days) on 4 hemispheres and late postoperative period (mean, 332.7 days) on 15 hemispheres. The labeling slab was positioned at the bypassed external carotid artery and 5 slices in each of the 10 sequential phases were acquired using a 3-T scanner. Results: Two of 4 early postoperative ASL examinations and all late postoperative ASL examinations demonstrated blood flow through the bypass. The remaining 2 early postoperative ASL examinations showed absence of blood flow; however, blood flow improved on follow-up examinations. Conclusion: Multiphase selective ASL technique can provide information about the dynamics of postoperative blood flow through the bypass in Moyamoya disease.