Objective: To explore whether dynamic susceptibility contrast MRI (DSC-MRI) could predict the effects and risk of indirect bypass surgery on MMD.
Methods: Clinical data of patients with MMD who were evaluated pre-and post-operatively with DSC-MRI and digital subtraction angiography (DSA) were retrospectively evaluated. 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 “non-responsible” hemispheres (2.66 +/- 1.34 vs. 1.57 +/- 1.09 sec). The postoperative MTT delay fell significantly in the cases whose symptoms disappeared (preoperative, 2.61 +/- 1.35 sec; postoperative, 1.35 +/- 0.96 sec). 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 sec). The MTT delay was significantly longer in patients with higher angiographical stages. Indirect bypass surgery ameliorated the MTT delay to the same degree in adults and children. The DSA revealed that the induced revascularization was far superior in areas with longer MTT delays.
Conclusion: DSC-MRI 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.
From: Practical Clinical Use of Dynamic Susceptibility Contrast Magnetic Resonance Imaging (DSC-MRI) for the Surgical Treatment of Moyamoya Disease by Ishii et al.