Comparison of computed tomography (CT) and contrast-enhanced ultrasound (CEUS) for the quantitative evaluation of an ablation defect following radiofrequency ablation of malignant liver lesions.

OBJECTIVE: To compare contrast-enhanced computed tomography (CT) and contrast-enhanced ultrasound (CEUS) for the quantitative evaluation of an ablation defect following radiofrequency ablation of malignant liver lesions in a prospective study.

MATERIALS AND METHODS: 22 radiofrequency ablations of malignant liver tumors were performed. The ablation defects were then measured and evaluated by two independent examiners via contrast-enhanced computed tomography (CT) and contrast-enhanced ultrasound (CEUS) using a 1-5 MHz multifrequency convex ultrasound transducer (LOGIQ E9, GE) with respect to the short-axis diameter, the long-axis diameter, and the area.

RESULTS: Quantitative evaluation of ablation defects is possible with both contrast-enhanced CT and CEUS. The average long-axis diameter was 47.1 mm (±11.08;±23,5%) on CEUS and 56.48 mm (±14.14;±25,0%) on CT; the short-axis diameter was 39.72 mm (±11.14;±28,05%) on CEUS and 40.27 mm (±10.50;±26,07%) on CT; the area was 1439.82 mm2 (±678.57;±47,13%) on CEUS and 2392.68 mm2 (1147.67;±48,0%) on CT. On average, ablation defects are assessed to be larger on CT than on CEUS. A significant correlation between the modalities could not be achieved for all measurement axes.

CONCLUSION: CEUS can be used for the postinterventional detection and evaluation of ablation defects. However, these are always assessed to be larger on contrast-enhanced CT than CEUS.