Radiofrequency ablation of small liver malignancies under magnetic resonance guidance: progress in targeting and preliminary observations with temperature monitoring

Objectives To evaluate the feasibility and effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation for small liver tumours with poor conspicuity on both contrast-enhanced ultrasonography (US) and computed tomography (CT), using fast navigation and temperature monitoring. Methods Sixteen malignant liver nodules (long-axis diameter, 0.6–2.4 cm) were treated with multipolar RF ablation on a 1.5-T wide-bore MR system in ten patients. Targeting was performed interactively, using a fast steady-state free precession sequence. Real-time MR-based temperature mapping was performed, using gradient echo–echo planar imaging (GRE-EPI) and hardware filtering. MR-specific treatment data were recorded. The mean follow-up time was 19 ± 7 months. Results Correct placement of RF electrodes was obtained in all procedures (image update,