Computed Tomography for Evaluation and Follow up of Hepatocellular Carcinoma after Microwave Ablation

Abstract

Background: When surgical procedures are not possible, image-guided HCC tumor ablation provides curative treatment or acceptable therapeutic choices in appropriately selected patients. Post-ablation tumor response evaluation is critical for assessing treatment effectiveness and further therapy. Ultrasound (US) and Computed Tomography (CT) are critical in the follow-up of patients who have undergone liver thermal ablation therapy. The purpose of this study was to evaluate the role of computed tomography for evaluation and follow-up of hepatocellular carcinoma following Microwave ablation. Methods: This prospective study was carried out on 30 patients radiologically proved with hepatocellular carcinoma. Results: Triphasic CT imaging arterial phase revealed homogenous enhancement lesions in 46.7% of patients and heterogeneous enhancement in 53.35% of patients. All the lesions showed early washout in Porto venous and delayed phases with a patent portal vein in all patients. The diameter of the ablated area was different according to the duration of ablation. 60 W was applied for 8-10 minutes, resulting in ablation zones of 3.5-4 x 4.7-5.2 cm whereas applications of 60 W for 10-15 minutes resulted in ablation zones with a size of 4.5 - 5.5 x 5.6-6.5 cm. Triphasic CT was performed after 1 month and revealed that the success rate was 93.8% for tumors measuring ≤ 3cm 92.9% for tumors measuring 3-5cm. Local tumor progression was shown in 2 patients (6%) after 1 month, in 3 patients (10%) after 3 months, and in 5 patients (16.7%) after 6 months of follow-up. There was an intrahepatic distant recurrence in 9 patients (30%) after 1 month, in 15 patients (50%) after 3 months, and in 18 patients (60%) after 6 months of follow-up. Conclusions: Percutaneous microwave ablation guided by ultrasound for the treatment of challenging HCC tumors up to 5 cm in diameter, including exophytic or subcapsular targets as well as those located in the hepatic dome or close to the diaphragm / hepatic hilum /heart, shown satisfactory efficacy and safety rates. For both technical and clinical success, selecting the proper approach is critical.