European Radiology Experimental · Published 2026-04-22 · DOI 10.1186/s41747-026-00711-4
Abstract Objective We evaluated ex vivo feasibility of ice-ball visualization during bone cryoablation using dual-energy computed tomography (DECT). Materials and methods This ex vivo study included three porcine cadavers on which cryoablation was performed on four vertebrae. Spectral DECT acquisitions were made at 0 and 10 min after ablation. Conventional images, virtual monoenergetic images (VMIs) at 50 keV, electron density (ED), effective atomic number (Zeff) and virtual non-calcium (VNCa) images were generated. Two radiologists assessed visibility and delineation of the ice-ball using a 4-point Likert scale. Quantitative analyses were made on HU VMI, VNCa noted HU*, ED, and Zeff in bone and adjacent tissues. Fused ED and VNCa images were assessed for each vertebra. For one pig, the fused ED and VNCa images were compared with post-ablation magnetic resonance imaging (MRI). Results For each pig, the ice-ball was visible in soft tissues on all spectral images except on Zeff images. The best contour delineation was observed on ED images for soft tissues, whereas the ice-ball was detectable in bone only on VNCa images, with poorer but acceptable contour delineation. Significant (p ≤ 0.039; effect size (ES) ≥ 0.84) changes in HU and ED were observed for the adjacent soft tissue. For bone, significant (p ≤ 0.043; ES ≥ 0.073) changes were found of ED and HU* on VNCa. ED/VNCa fusion improved ice-ball delineation in bone, confirmed by comparison with MRI. Conclusion The fusion of spectral ED and VNCa images could show potential in improving the visualization of the ice-ball during bone cryoablation. Relevance statement Fusion of electron density and virtual non-calcium images enhances the ice-ball visualization in bone during spinal cryoablation. Key Points The lack of visibility of the ice-ball in the bone during cryoablation represents a limitation for the safety of adjacent structures at risk. In bone, the ice-ball was detectable only on virtual non-calcium (VNCa) images, but the quality of its contour delineation was poorer. Electron density and VNCa fusion images improved ice-ball visualization and delineation in bone, as confirmed by comparison with MRI. Graphical Abstract
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