[Potential advantages of the MRI for the radiofrequency ablation of liver tumors]. / Potenzial der MRT für die Radiofrequenzablation von Lebertumoren.

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 %. CONCLUSION: MR-compatible RF applicators offer the opportunity for intra-interventional detection of residual tumor during RF ablations by use of sensitive MRI sequences. These procedures may lead to a higher confidence in tumour ablation and may reduce the number of re-interventions and local recurrences of intrahepatic tumors.

[Current status of MRI diagnostics with liver-specific contrast agents. Gd-EOB-DTPA and Gd-BOPTA]. / Aktueller Stand der MRT-Diagnostik mit leberspezifischen Kontrastmitteln. Gd-EOB-DTPA und Gd-BOPTA.

The contrast agents Gd-EOB-DTPA and Gd-BOPTA can be administered by bolus injection and are appropriate for use in MRI both as vascularization markers and markers of hepatobiliary excretion. This contribution presents an overview of the specific characteristics of contrast media and the status of clinical development. In comparison to CT and to MRI with unspecific extracellular Gd-chelates, liver-specific contrast agents offer advantages in differentiating unclear liver lesions, increasing the detection rate, and examining the bile duct system.

[Current concepts and recent developments of laser ablation in tumor therapy]. / Aktueller Stand und Entwicklungen der Laserablation in der Tumortherapie.

PURPOSE: The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. METHODS; Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors-bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. RESULTS: In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. CONCLUSIONS: The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results.