Post-embolization dynamic changes in Obsidio Conformable Embolic: volume and radiodensity analysis

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.

This retrospective, single-center cohort study included 21 patients (30 vessels) embolized with Obsidio for acute hemorrhage or hypervascular tumor between 2023 and 2026. Patients had at least two follow-up computed tomography (CT) scans. 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.

All embolizations were technically successful (100%). On the first follow-up CT (median 12 days), the mean Obsidio volume was 89.33 ± 13.86% of the original volume (p = 0.0002). On the second follow-up (median 36 days), the volume was 79.51 ± 19.76% of baseline volume (p = 0.0004), representing 20.49% reduction. On third follow-up CT (median 76 days), volume was 85.2 ± 18.92% (p = 0.047). On the fourth follow-up CT, volume was 66.76 ± 16.9% (p = 0.0048). On the fifth follow-up CT, volume was 60.15 ± 3.15% (p = 0.00001) The average volume reduction rate decelerated from 0.99%/day to 0.71%/day to 0.17%/day then stabilized at 0.2%/day. Concurrently, mean Hounsfield unit attenuation increased by 4.85% (p = 0.06) on the second follow-up CT scan. No evidence of recanalization, distal embolization, or cast fragmentation was observed on any of CT scans.

The Obsidio embolic cast undergoes progressive reduction in volume and increase in HU attenuation over time 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.