Image-guided microwave ablation of hepatocellular carcinoma (≤5.0 cm): is MR guidance more effective than CT guidance?

BACKGROUND: Given their widespread availability and relatively low cost, percutaneous thermal ablation is commonly performed under the guidance of computed tomography (CT) or ultrasound (US). However, such imaging modalities may be restricted due to insufficient image contrast and limited tumor visibility, which results in imperfect intraoperative treatment or an increased risk of damage to critical anatomical structures. Currently, magnetic resonance (MR) guidance has been proven to be a possible solution to overcome the above shortcomings, as it provides more reliable visualization of the target tumor and allows for multiplanar capabilities, making it the modality of choice. Unfortunately, MR-guided ablation is limited to specialized centers, and the cost is relatively high. Is ablation therapy under MR guidance better than that under CT guidance? This study retrospectively compared the efficacy of CT-guided and MR-guided microwave ablation (MWA) for the treatment of hepatocellular carcinoma (HCC ≤ 5.0 cm). METHODS: In this retrospective study, 47 patients and 54 patients received MWA under the guidance of CT and MR, respectively. The inclusion criteria were a single HCC ≤ 5.0 cm or a maximum of three. The local tumor progression (LTP), overall survival (OS), prognostic factors for local progression, and safety of this technique were assessed. RESULTS: All procedures were technically successful. The complication rates of the two groups were remarkably different with respect to incidences of liver abscess and pleural effusion (P < 0.05). The mean LTP was 44.264 months in the CT-guided group versus 47.745 months in the MR-guided group of HCC (P = 0.629, log-rank test). The mean OS was 56.772 months in the patients who underwent the CT-guided procedure versus 58.123 months in those who underwent the MR-guided procedure (P = 0.630, log-rank test). Multivariate Cox regression analysis further illustrated that tumor diameter (< 3 cm) and the number of lesions (single) were important factors affecting LTP and OS. CONCLUSIONS: Both CT-guided and MR-guided MWA are comparable therapies for the treatment of HCC (< 5 cm), and there was no difference in survival between the two groups. However, MR-guided MWA could reduce the incidence of complications.