Abstract No. 166 ▪ FEATURED ABSTRACT Bariatric Arterial Embolization is Associated with Significant Muscle-Sparing Weight Loss Detected by Whole-Body Magnetic Resonance Imaging Anthropometry

To evaluate the early effects of bariatric arterial embolization (BAE) on multi-compartment fat and muscle body composition. This report is the pilot phase of the BEATLES trial Bariatric Embolization of ArTeries with imaging visibLe EmbolicS. BEATLES is an IRB and FDA-approved physician-initiated investigational device exemption study that evaluates tightly calibrated 100-200μm radiopaque microspheres (BT-001933-01, Boston Scientific Corporation). Adult participants with obesity (BMI ≥35kg/m2) were scanned at 0 (baseline), 3 and 6-months post-BAE from neck to knees in a Siemens Skyra 3T MRI system using a dual-echo Dixon water-fat Vibe protocol, and a single-slice multi-echo Dixon proton liver density acquisition. Anthropometrics were obtained using AMRA Researcher (AMRA Medical AB, Linköping, Sweden), a semi-automated cloud-based MRI segmentation tool.1 Statistical testing was performed via repeated measures correlation (Rrm).2 Seven patients (mean age, 39.6 ± 11.0 years, 6 females) with CDC class II-III obesity underwent BAE. At 0, 3, and 6-months, mean body weight was 125.9 ± 24.4, 113.5 ± 21.2, and 110.7 ± 23.3 kg (Rrm = -0.694 [95% CI -0.921 to -0.113], P = 0.012). Weight-to-thigh muscle volume ratios were 10.3 ± 1.9 10.0 ± 0.5, and 9.2 ± 1.3 kg/L (Rrm = 0.89 [95% CI 0.64-0.97], P value = 0.001), respectively. Postprocedural anthropometry is summarized in Table 1. BAE using 100-200 μm microspheres is associated with significant post-procedural muscle-sparing weight loss via subcutaneous and intra-muscular fat reduction.