Evaluation of Cerebral Hemodynamics with Perfusion MRI in Childhood Moyamoya Disease

The purpose of our study was to evaluate the role of perfusion MRI and to compare the findings with those of conventional imaging in childhood moyamoya disease (MMD). Perfusion MRI was performed preoperatively on 13 cases of childhood MMD. Based on the perfusion MRI findings, patients were classified into four groups: those with normal regional cerebral blood volume (rCBV) and time to peak (TTP) (group 1, n = 2); those with normal rCBV and delayed TTP (group 2, n = 1); those with increased rCBV and delayed TTP (group 3, n = 5), and those with decreased rCBV and delayed TTP (group 4, n = 5). Lesion volume as determined using the rCBV map was compared with that on MRI and single photon emission computerized tomography (SPECT). The characteristics of groups 1, 2 and 3 were a high frequency of transient ischemic attacks, normal finding on MRI, early angiographic stages, decreased reserve on SPECT and favorable operative outcome. In group 3, angiography revealed abundant collateral channels. In group 4, all cases had infarction on MRI and abnormal perfusion on SPECT. Angiographic stages tended to have progressed, and operative outcome was less favorable. Perfusion MRI documented hemodynamic asymmetries in the five cases with normal MRI. Perfusion MRI is suggested to have a sensitivity intermediate between rest and acetazolamide SPECTs. We conclude that perfusion MRI may be a valuable tool for characterizing and monitoring ischemia in MMD. Perfusion MRI provides additional functional information not available from conventional MRI and has a potential role comparable to SPECT in the evaluation of MMD.