Oblique approach for CT-guided liver radiofrequency ablation using multiplanar reformation images in hepatocellular carcinoma

Purpose To evaluate the feasibility and safety of CTguided radiofrequency (RF) ablation by caudal-cranial oblique insertion using multiplanar reformation (MPR) images for hepatocellular carcinomas (HCCs). Materials and methods Twenty-two HCCs in 19 patients that were difficult to demonstrate on ultrasound (mean tumor diameter was 17.5 mm) were treated with CT-guided RF ablation by caudal-cranial oblique insertion to avoid pneumothorax, using MPR images after transcatheter arterial chemoembolization. The insertion point and direction of insertion, avoiding aerated lung parenchyma, bones, large vessels, and intestine, were sought on the MPR images. Technical success was defined as complete eradication of tumor enhancement in the contrast-enhanced CT. Local tumor progression was defined by the appearance of enhanced tumor adjacent to the zone of ablation. The technical success rate, local tumor progression, and complications were investigated. Results The coronal plane was used for insertion in 18 tumors, the sagittal plane in 3 tumors, and the oblique plane in 1 tumor. RF electrode placement was successful and complete necrosis was obtained in all cases. During the mean follow-up period of 38.0 months, local tumor progression was not detected in any of the patients. There were no major complications, including pneumothorax. Conclusion CT-guided RF ablation by caudal-cranial oblique insertion using MPR images is a feasible and safe therapeutic option.