Three-dimensional Contrast-enhanced Ultrasound for Evaluating the Shape and Size of the Microwave Ablation Zone

To investigate the agreement between three-dimensional contrast-enhanced ultrasound (3D-CEUS) and contrast-enhanced computed tomography (CECT) in assessing microwave ablation (MWA) zone dimensions (size and morphology) in clinical practice, and to quantify differences in ablation characteristics between human patients and ex vivo bovine liver models, thereby optimizing preoperative planning models.

This retrospective study enrolled 33 patients with malignant liver tumors who underwent single-needle, single-insertion percutaneous MWA guided by ultrasound at the department of ultrasound in Tianjin Third Central Hospital from January 1, 2022, to January 31, 2024. We determined the correlation and consistency of 3D-CEUS and CECT in evaluating the long axis diameter (LAD), short diameter (DS), volume, and roundness index (RI) of the MWA zone. We also compared the shape and size of the ablation zones in ex vivo bovine liver models with those of clinical MWA zones.

Significant correlations were observed between 3D-CEUS and CECT in evaluating the shape and size of MWA ablation zones. Correlations between both methods were very strong for volume, DS1, and RI (Pearson; 0.96, 0.90, and 0.87) and LAD and DS2 (Spearman; 0.97 and 0.87). 3D-CEUS and CECT showed excellent-to-good consistency in evaluating the parameters of ablation lesions (p < 0.001), with intraclass correlation coefficients ranging from 0.81 to 0.95. Ex vivo bovine liver ablation zones exhibited significantly larger LAD, DS1, DS2, and RI measurements compared with clinical cases (p < 0.001), consistent across both imaging modalities.

We found that 3D-CEUS exhibits high accuracy in assessing MWA zone morphology and dimensions. The integration of clinical 3D-CEUS data, rather than data from ex vivo experimental models, would enhance the precision of the preoperative planning system for thermal ablation procedures.