Radiofrequency ablation of hepatocellular carcinoma close to stomach with balloon interposition

Clinical History

A 45-year-old male with history of chronic liver disease underwent an ultrasound abdomen which showed a mass in the left lobe. He then underwent a computed tomography (CT) outside consistent with hepatocellular carcinoma (HCC). He was referred for radiofrequency ablation (RFA).

Imaging Findings

Figures 1 a-f.
a) Axial contrast enhanced CT performed outside showing a fairly well defined homogenously enhancing left lobe nodular hepatoma abutting stomach with no clear intervening fat plane.
b) Under CT guidance, a sheath seen as a thin linear structure was introduced from the left side of the abdomen. The balloon passed via sheathand inflated is seen as a hyperdense structure placed between the stomach and the left lobe of liver.
c) Ultrasound showing the hypoechoic HCC. Inferiorly, the inflated balloon is seen as a double reflective structure.
d) Patient on table in CT gantry. Radiiofrequency (RF) ablation needle is seen inserted from the right side of the patient. On the left side, the long sheath and balloon were introduced.
e) Ablation process going on, the lesion is obsured with the formation of microbubbles. RF needle can be visualised.
f) Follow up CT taken at 6 weeks shows no thermal injury to the stomach and complete response of the lesion.

Discussion

RFA is an effective, minimally invasive technique for treating HCC. Based on the thermal ablation principle, RFA with a percutaneously inserted electrode ablates tumours, and is now reportedly accepted as a first line therapy for small HCC because of its local therapeutic efficacy, low complications, and reduced hospitalization.

HCC in high-risk location are those close to large vessels/extrahepatic organs, and are at risk of unintended thermal injury from RFA. Nodules adjacent to extrahepatic organs are those located <5mm from the heart, lung, gallbladder, right kidney, gastrointestinal tract [1]. Additionally, local tumour progression, which is recurrence occurring either abutting/within the previous ablation zone, is reportedly higher if the tumour is in a high-risk location [2].

This patient showed an HCC nodule in contact with the stomach. The risk of gastric perforation was high with conventional ablation. We therefore used a standard balloon catheter, commonly used for angioplasty, to displace the stomach from the nodule. Under CT guidance, a sheath was advanced until the peritoneal cavity was reached to secure access. Under CT guidance, a 8 mmx4 cm balloon was passed via the sheath, and then placed between the stomach and liver. The balloon was inflated with very diluted iodine contrast solution. Adequate separation was documented by CT before the ablation began. We used an internally cooled electrode system. A 3cm new RF needle was introduced and was targeted to the nodule. Time of ablation was 12 minutes. Post-procedure, no major complication was noted. Follow-up CT taken shows no thermal injury or perforation to the stomach and complete response of the target lesion.

The balloon was used for the first time as a pilot study in our department. We frequently perform a safe alternative technique, hydrodissection in high-risk located HCCs. 5% dextrose/saline/sterile water is instilled into intra/retroperitoneal spaces to displace adjacent organs. The volume of instilled fluid varies considerably (from 100-1000cc) depending on the tumour location and on the fluid seepage into adjoining anatomic spaces. In cases where fluid seepage and the risk of quick absorption, continuous infusion may be required. The main limitations of hydrodissection are incomplete success in peritoneal adhesions due to previous treatments(surgical resection, TACE, ablation)and tumour in the bare area of liver [3-5]. Reported complications include hemoperitoneum, peritonitis, tumour seeding [6].

In summary, balloons offer protection via physical displacement and to act as a thermal blanket. The balloon interposition may be used as a primary protective technique or when other options such as hydro-/pneumodissection have failed. This patient had successful ablation of his HCC.

Differential Diagnosis List

Final Diagnosis

Successful radiofrequency ablation of high-risk location HCC with balloon interposition

URL:	https://www.eurorad.org/case/14248
DOI:	10.1594/EURORAD/CASE.14248
ISSN:	1563-4086