Abstract TP488: Postoperative Remodeling of Donor Arteries on MR Angiography Can Predict Development of Surgical Collaterals in Moyamoya Disease

Abstract

Object: The calibers of donor arteries can change dynamically after bypass surgery in moyamoya disease (MMD). The present study aimed to evaluate the cut-offs of caliber changes in donor arteries associated with good surgical revascularization and to assess the impact of clinical factors potentially related to bypass development. Methods: We studied 71 hemispheres of 30 adults and 16 children with MMD, who underwent combined revascularization. We quantitatively measured the calibers of the superficial temporal artery (STA), deep temporal artery (DTA), and middle meningeal artery (MMA) with magnetic resonance angiography (MRA) source images and calculated the postoperative caliber change ratios (CCRs), to assess direct and indirect bypass development. They were compared with the findings of digital subtraction angiography, in which revascularization areas were categorized into 3 groups (poor, good, and excellent). Results: In both adult and pediatric hemispheres, median STA and DTA CCRs were higher in better revascularization groups (p < 0.05), while MMA CCRs were not significantly different among the groups. Receiver operation characteristic analysis revealed that the cut-off of >1.1 and >1.3 STA CCRs were associated with good direct revascularization in adult and pediatric hemispheres, respectively. The cut-off of >1.6 and >1.2 DTA CCRs were associated with good indirect revascularization in adult and pediatric hemispheres, respectively. Considering these cut-off values, STA and DTA CCRs showed high median values, irrespective of age, severity of cerebrovascular reserve, disease stage, and disease onset type. Conclusions: Caliber changes in STA and DTA can be easily measured by MRA, which could be indicators of direct and indirect bypass development. The combined bypass procedure could maximize revascularization in both adults and children with MMD.