2079 Assessment of MRI Vessel Wall Imaging as a Predictive Factor for Bypass Outcomes in Moyamoya Disease

INTRODUCTION: Ipsilateral vessel wall enhancement (VWE) has been associated with Moyamoya disease (MMD) progression. However, the effect of revascularization surgery on VWE has not been determined. METHODS: Retrospective review of patients undergoing revascularization surgery for MMD between 2020 and 2023. RESULTS: Twenty-six patients with MMD (8 bilateral, or 34 hemispheres) underwent either combined direct-indirect (n=29, 85%) or indirect only (n=5, 15%) bypass surgery. Median age at surgery was 44 years with 23 females (68%). Median follow-up was 17 months. Modified Rankin score (mRS) at presentation typically ranged 0-2 (n=30, 88%) with 4 patients (12%) having mRS of 3. Twenty-four patients (71%) had VWE ipsilateral to bypass pre-operatively. Patients with pre-operative VWE had a higher mRS both at presentation (p=0.003) and last follow up (p=0.009), and a higher rate of bilateral disease (p=0.014). All 10 patients without pre-operative VWE had stable or improved neurologic status at last follow-up, compared to 20 of 24 with pre-operative VWE (p=0.296). Of 29 patients with post-operative MRI, 20 (69%) had no change in VWE, while 4 (14%) had a decrease and 5 (17%) had an increase. Amongst 5 patients who had an increase in VWE post-operatively, all demonstrated stable/improved neurologic status on clinical follow up, and 3 of 5 had an improved perfusion outcome. For patients with decreased VWE, all demonstrated stable/improved neurologic status on clinical follow up, and 3 of 4 had an improved perfusion outcome. VWE changes did not correlate with revascularization grade (p=0.195). CONCLUSIONS: Within a limited cohort, revascularization surgery had an inconsistent effect on the degree of VWE. Pre-operative VWE was not associated with neurologic outcomes in patients undergoing bypass surgery. Larger cohorts with more extended follow-up are required for further assessment.