Melanoma liver metastases with special imaging features on magnetic resonance imaging after microwave ablations: How to evaluate technical efficacy?

ABSTRACT

Purpose: To evaluate the technical feasibility of microwave ablation (MWA) for melanoma liver metastases with persistent high signal on magnetic resonance imaging (MRI). Materials and Methods: Seven patients with 22 target melanoma liver metastases who underwent MWA treatment were included. All procedure-related complications were observed and recorded. One month after MWA, the imaging features of treated liver metastases and ablation zones with different MRI sequences were reviewed to evaluate technique efficacy. To verify the correctness of the evaluation, MRI scans during patient follow-up were reviewed and compared with images before MWA to analyze changes in treated liver metastases and ablation zones. Results: All ablations were performed successfully, and there were no procedure-related major complications. After ablation, according to MRI T1-weighted pre-contrast or contrast sequences, the persistence of high signals from the treated lesions was noted inside the ablation zones of 19 lesions. Among these 19 lesions, 17 were completely covered by the ablation zones and were considered successfully treated, whereas two lesions were not completely covered and were considered unsuccessfully treated. Three lesions could not be detected on any MRI sequence after ablation and were also considered successfully treated. Finally, MRI scans during patient follow-up care verified these evaluations. Conclusion: MWA is a technically feasible option for melanoma liver metastases with special imaging features on MRI