Percutaneous Radiofrequency Ablation of Small (1–2 cm) Hepatocellular Carcinomas Inconspicuous on B-Mode Ultrasonographic Imaging: Usefulness of Combined Fusion Imaging with MRI and Contrast-Enhanced Ultrasonography

Figure 3

Images from a 59-year-old woman with a 1.1-cm HCC and hepatitis B virus-related liver cirrhosis who had previously undergone percutaneous RFA of HCC.

(a) Arterial-phase MRI showing a small hypervascular HCC (arrow) in segment 5 of the liver. Arrowheads indicate a previous RFA zone

(b) After fusion imaging, the HCC nodule could not be identified on B-mode US imaging at the corresponding site on fused MRI (arrow). Therefore, the index tumor was given a conspicuity score of 4 on fusion imaging as it was definitely unidentifiable

(c) On arterial-phase imaging obtained after the second injection of Sonazoid, a small enhanced lesion (arrow) was clearly identifiable at the corresponding location on fused MRI. After the first injection of the contrast agent, the optimal arterial phase was not obtained due to irregular respiration of the patient

(d) On post-vascular-phase imaging, the index tumor (arrow) was clearly identified as a perfusion defect at the corresponding site (arrow) on fused MRI. Therefore, the index tumor was given a conspicuity score of 1 on CEUS-added fusion imaging

(e) An RF electrode (arrowheads) was inserted into the index tumor (arrow) under CEUS-added fusion imaging guidance, after which RF energy was applied

(f) Arterial-phase CT image obtained immediately after RFA revealed technical success with sufficient ablative margins (arrowheads). LTP was not identified on follow-up MRI obtained 32 months after RFA (not shown here)