Asymmetric Cortical Vessel Sign Indicates Hemodynamic Deficits in Adult Patients with Moyamoya Disease

Asymmetric cortical vessel sign (ACVS) on susceptibility-weighted imaging (SWI) indicates elevated concentration of deoxyhemoglobin and elevated oxygen extraction fraction in patients with cerebral ischemia. This study aimed to clarify whether ACVS is associated with impaired hemodynamics and hyperperfusion syndrome in patients with moyamoya disease (MMD).Consecutive adult patients with MMD were enrolled. ACVS data on SWI and perfusion data using dynamic perfusion computed tomography were obtained and evaluated preoperatively and on postoperative days 2 and 180.A total of 24 patients with MMD were enrolled. Of 11 (45.83%) patients showing positive ACVS before surgery, 8 turned negative on postoperative day 2 and 9 showed absence of ACVS 180 days after surgery. Regions of interest showing positive ACVS had lower cerebral blood flow (CBF, P<0.001), increased cerebral blood volume (P = 0.021), prolonged time to peak (P<0.001), and mean transit time (P = 0.009). No patients with hemorrhagic symptoms showed positive ACVS(P = 0.041) and patients with positive ACVS showed more increase in CBF (P<0.004).In patients with MMD, ACVS on SWI indicates severe impairment in hemodynamics and is associated with more increase in CBF after bypass surgery. Hence, ACVS on SWI might be considered as a neuroimaging marker for the evaluation of hemodynamics in patients with MMD.