Radiofrequency ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles (Sonazoid) for hepatic malignancies: an initial experience

Abstract

Conventional contrast harmonic sonography has the technical problem of a short enhancement time during targeting of hepatic malignancies for radiofrequency (RF) ablation. This study investigated the effectiveness of contrast harmonic sonographic guidance using perfluorocarbon microbubbles (Sonazoid) during RF ablation of hepatic malignancies. Nodules were detected on contrast-enhanced computed tomography, but could not be resolved clearly by B-mode sonography. Sixty-six patients (51 men, 15 women; mean age, 65.8 years) with 108 hepatic malignancies were enrolled. Fifty-one patients with hepatocellular carcinoma and 15 patients with liver metastases were treated by RF ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles for a target lesion identified as a defect image after the administration of contrast medium. The maximal diameters of all tumours ranged from 0.7 to 3.5 cm (mean +/- SD, 1.7 cm +/- 0.9) on sonography. Complete tumour necrosis was achieved by a single session of RF ablation in 62 (94%) of the 66 patients, while two sessions were required for the remaining four (6%) patients. The average number of treatment sessions was 1.1 +/- 0.3. In the post-vascular phase, 105 (97%) of a total of 108 malignant hepatic tumours were depicted as a defect with a margin. Clinical courses have been satisfactory without any signs of local tumour progression during 1-12 months of follow-up (mean, 4.3 months). Using perfluorocarbon microbubbles, contrast harmonic sonographic-guided RF ablation is an efficient approach for guiding further ablation of hepatic malignancies that are not clearly demarcated by B-mode sonography.