Efficacy of Contrast-Enhanced US versus CT or MRI for the Therapeutic Control of Percutaneous Radio-frequency Ablation in the Case of Hepatic Malignancies

Purpose: The goal of this study was to assess the informative value of contrast-enhanced ultrasound after radiofrequency ablation (RFA). Patients who had undergone RFA of malignant liver tumors were followed up with contrast-enhanced sonography (CEUS), computed tomography (CT) and/or magnetic resonance tomography (MRI), and the outcomes were compared. Materials and Methods: 76 patients undergoing 194 RFAs for 118 hepatic neoplasms (n = 55 HCC, n = 63 metastases) in the course of a 7-year period were examined post-interventionally using CEUS and CT or MRI. During follow-up (gold standard of evaluation), contrast agent rim accumulations with a diameter greater than 5 mm and a growth rate of at least 25% were counted as a recurrence. Results: CEUS-CT comparison group: A total of 65 scan pairs were compared. In 54 cases (83.1%) the findings were the same with either method. In 7 cases (10.8%) CEUS confirmed the correct diagnosis, and in 2 cases (3.1%) only CT was correct. In 2 cases (3.1%) both methods yielded incorrect results. Diagnostic accuracy (DA): CEUS 93.8%, CT86.2%. CEUS-MRI comparison group: In 23 cases (88.5%) of a total of 26 scan pairs, the findings were the same for both CEUS and MRI. In 3 discordant cases only CEUS confirmed the correct diagnosis (3 cases, 11.5%). Diagnostic accuracy DA (n =26): CEUS 100%, MRI 88.4%. Conclusion: CEUS performs equally to CT and MRI in the follow-up of patients treated for liver tumors by RFA.