Post-Embolization Dynamic Changes in Obsidio Conformable Embolic: Volume and Radiodensity Analysis

Purpose: To characterize the temporal dynamic and clinical remodeling of the Obsidio Conformable Embolic™ (Obsidio) post endovascular delivery using longitudinal quantitative CT volumetry and Hounsfield unit (HU) attenuation. Materials and Methods: This retrospective, single-center cohort study included 13 patients (19 vessels) embolized with Obsidio for acute hemorrhage or hypervascular tumor between 2023 and 2025. Patients had at least two follow-up computed tomography (CT) scans within 60 days post-procedure. The primary endpoint was the percent change in embolic cast volume and HU attenuation, measured using standardized Picture Archiving and Communication System (PACS) segmentation tools. Secondary endpoints included assessment for recanalization. Results All embolizations were technically successful (100%). On the first follow-up CT (mean 12 days), the mean Obsidio volume was 93.00 ± 10.56% of the original volume (95% CI: 87.91–98.09, p = 0.0098). On the second follow-up (mean 21 days), the volume was 80.77 ± 18.50% of baseline volume (95% CI: 68.34–93.20, p = 0.0063), representing 19.23% reduction. The average volume reduction rate decelerated from 1.15%/day to 0.99%/day. Concurrently, mean Hounsfield unit attenuation increased by 5.26 ± 7.57% (p = 0.044) on the final follow-up CT scans. No evidence of recanalization, distal embolization, or cast fragmentation was observed on any of CT scans. Conclusion The Obsidio embolic cast undergoes progressive reduction in volume and increase in HU attenuation over two months without evidence of vessel recanalization. This temporal dynamic of Obsidio embolic is consistent with bioresorption of its gelatin and water components, supporting the concept of persistent occlusion via in vivo remodeling.