4D flow analysis of whole-brain cerebral blood flow in patients with Moyamoya disease before and after direct revascularization—A pilot study

Motivation: The hemodynamic changes after superficial temporal artery-middle cerebral artery (STA-MCA) bypass in patients with Moyamoya disease (MMD) remain unclear. 4D flow is expected to provide more information about the hemodynamic parameters of patients with MMD before and after surgery. Goal(s): To clarify the hemodynamics by comparing flow parameters obtained by 4D flow magnetic resonance imaging (MRI). Approach: Patients with MMD were prospectively recruited for 4D flow magnetic resonance scanning before and after bypass surgery. Results: After bypass surgery, the contralateral internal carotid artery blood flow decreased and cerebral blood flow was redistributed. Impact: The results indicate that 4D flow MRI is a feasible, noninvasive alternative for evaluating bypass grafts in the early postoperative period. These flow parameter values may help improve the way patients are evaluated after bypass surgery.