Percutaneous radiofrequency ablation of sonographically unidentifiable liver tumors. Feasibility and usefulness of a novel guiding technique with an integrated system of computed tomography and sonographic images

Abstract

Objective: The purpose of this study was to evaluate the safety and feasibility of a real-time integrated system with computed tomography (CT) and sonographic images for radiofrequency (RF) ablation of hepatic malignancies poorly defined on B-mode sonography, and to clarify the suitable phase of CT images for using this virtual sonography.

Methods: Between September 2004 and December 2004, 12 patients with 16 hepatocellular carcinomas and two metastatic lesions arising from colorectal adenocarcinoma (n = 1) and rectal carcinoid (n = 1) were treated. The maximum diameter of nodules ranged from 1.0 to 2.5 cm (mean +/- SD; 1.5 +/- 0.6 cm) on CT images.

Results: Complete tumor necrosis was achieved in a single session in 19 lesions (90%), while a second session was required for the remaining two lesions (10%). Portal phase multi-planar reconstruction images were displayed under a suitable position corresponding to the ultrasound images in 9 patients (HCC = 7, metastasis = 2), and arterial phase multi-planar reconstruction images were displayed in the 3 remaining patients with hepatocellular carcinoma.

Conclusion: Percutaneous RF ablation guidance using virtual sonography is an effective treatment for patients with hepatic malignancies. The portal phase of CT images may be the most suitable to indicate the 3-dimensional relationship between the liver vasculature and tumors on virtual sonography.