Fig. 8. Fusion imaging and contrast-enhanced ultrasonography (CEUS)-guided radiofrequency ablation (RFA) of a 1.3-cm hepatocellular carcinoma (HCC) in a patient with a hepatitis B virus carrier.

A. Arterial-phase T1-weighted magnetic resonance (MR) image shows a small enhancing lesion (arrow) in the periphery of segment 6 of the liver. B. The lesion (arrow) shows a low signal intensity in the hepatobiliary phase. C. Fusion imaging-guided RFA was performed. On the US of the fusion imaging, a small low echoic lesion (arrow) was identified at the similar location (arrow) of the tumor on the fused MR image. D. However, to obviate the risk of mistargeting, CEUS was performed additionally. On CEUS, the lesion identified on fusion imaging (C) did not show arterial enhancement. True HCC was obscured by a rib shadow and was identified as a small enhancing lesion when the patient breathed in slightly when the liver was slightly shifting down (not shown here, Video clip 3). The lesion was targeted with the patient holding the breath after inhaling a small amount of air in the Kupffer phase when the index tumor (arrow) was seen as a defect. The arrowheads indicate the exposed tip of the electrode. E. Immediate post-RFA computed tomography scan shows that the tumor was completely covered by the ablation zone (arrowheads), suggestive of technical success. In this example, mistargeting was avoided by the use of CEUS in addition to fusion imaging.