Magnetic resonance imaging-guided microwave ablation of hepatic malignancies: Feasibility, efficacy, safety, and follow-up.

Abstract

Percutaneous image-guided thermal ablation has emerged as a valuable therapeutic approach for hepatic malignancies. Magnetic resonance imaging (MRI) has shown potential for great soft-tissue resolution and multiplanar capabilities in arbitrary imaging planes, which are also critical for treatment planning, targeting, and evaluation. The aim of this study was to investigate the feasibility, technical success, safety, and follow-up of hepatic malignancies treated with MRI-guided microwave ablation (MWA). MRI-guided MWA was performed in a closed-bore 1.5 T MR system. T1-weighted imaging was used as a monitoring tool during surgery. T2-weighted imaging was performed to obtain an adequate tumor margin, to calculate the tumor size. Multi-b-value diffusion-weighted imaging (DWI) was performed postprocedurally. Enhanced MRI was performed at 4 weeks, to assess the technical success, and every 3-6 months as a follow-up. Twenty-six patients (38 lesions) were enrolled in the study. A primary efficacy rate of 100% was achieved, and no major complications were observed. Two patient cohorts were identified based on lesion size. Six lesions with incomplete circles on reconstructed DWI appeared immediately postprocedure, and persistent hyperintense signals developed into new lesions over the subsequent 6-12 months. MRI-guided ablation is feasible and effective for planning and evaluating MWA in hepatic malignancies. The available clinical data strongly support the advantages of the assessment of tumors through 3D imaging versus routine axial images.