Potential advantages of the MRI for the radiofrequency ablation of liver tumors

Purpose: to present first results of radiofrequency ablation of liver tumors using a new MR compatible applicator. Materials and methods: we performed 37 interventions in 20 patients (mean age 58.6 years) with primary intrahepatic malignancies or metastases: colorectal carcinoma n = 6, hepatocellular carcinoma n = 3, pancreatic carcinoma n = 4, sarcoma n = 2, cholangiocellular carcinoma n = 1, carcinoma of the tonsil n = 1, breast carcinoma n = 1, gastric carcinoma n = 1, and gastrointestinal stroma tumor n = 1. Interventions were performed under CT-guidance with CT fluoroscopy (n = 32) and under MR-guidance (n = 5) using fast T1-weighted sequences in breath-hold technique. RFA was performed with the RF-generator (150 W) under local anesthesia and sedation using MR compatible applicators (Starburst XL, rita medical systems, USA) together with the appropriate soft tissue introducer system. Intra-interventional control was performed with intrahepatically or intralesionally placed introducer system or applicator. MRI was performed with plain breath-triggered T2-weighted turbo spin echo sequences (TSE T2) with fat saturation. Results: all interventions were performed without major events. The mean diameter of induced coagulation was 4.0 (±0.7) cm. Repositioning was necessary in 8 interventions (21%) after detection of residual tumor on an intra-interventional MRI. After a mean follow-up of 6.5 (± 1.2) months, the local tumor control rate was 92%. (orig.)