BACKGROUND: Precise evaluation of hemodynamic stress is important for the treatment of moyamoya disease (MMD).
OBJECTIVE: To explore whether dynamic susceptibility contrast magnetic resonance imaging could predict the effects and risk of indirect bypass surgery on MMD.
METHODS: Clinical data of patients with MMD who were evaluated preoperatively and postoperatively with dynamic susceptibility contrast magnetic resonance imaging and digital subtraction angiography were evaluated retrospectively. Indirect bypass surgery was performed on 115 hemispheres of 69 patients (mean age, 15 years; range, 3-54 years). We examined the correlations of ischemic events and revascularization with the mean transit time (MTT) delay to cerebellum.
RESULTS: The hemispheres that caused the ischemic events (responsible hemisphere) had a significantly longer preoperative MTT delay than the nonresponsible hemispheres (2.66 ± 1.34 vs 1.57 ± 1.09 seconds). The postoperative MTT delay fell significantly in the patients whose symptoms disappeared (preoperative, 2.61 ± 1.35 seconds; postoperative, 1.35 ± 0.96 seconds). Perioperative infarction occurred in 4 hemispheres (3.5%), and the MTT delay was significantly longer in those hemispheres than in the others (3.97 ± 1.20 vs 2.38 ± 1.34 seconds). The MTT delay was significantly longer in patients with higher angiographic stages. Indirect bypass surgery ameliorated the MTT delay to the same degree in adults and children. Digital subtraction angiography revealed that the induced revascularization was far superior in areas with longer MTT delays.
CONCLUSION: Dynamic susceptibility contrast magnetic resonance imaging proved to be a useful clinical imaging method for patients with MMD. It may be helpful for selecting candidates for MMD intervention and for predicting the effects and risks of surgery.
ABBREVIATIONS: DSC-MRI, dynamic susceptibility contrast magnetic resonance imaging
MMD, moyamoya disease
MTT, mean transit time
ROI, region of interest