Major RF Ablations of Hepatomas Under MR Thermometry Monitoring

Overview

Object of the study: To assess the effectiveness of MR temperature monitoring of RFA of large hepatocellular carcinomas (HCC) (≥ 5 cm) in terms of complete tumor necrosis rate achieved and in term of reduction of the number of procedure required to obtain complete ablation of the tumors. Experimental plan : This pilot study consist to perform in a single center a single procedure of the multipolar RF ablation under MR temperature monitoring for the treatment of up to three HCC with diameter ranging from 5 cm and 10 cm in 20 inoperable patients. The main judgement criterion of the study will be the rate of complete ablation one month after one RFA procedure performed under MR temperature monitoring. The secondary criteria are, the 2-years local recurrence rate (after the first initial RF ablation procedure performed under MR temperature imaging ± additional RF ablation procedures under ultrasound monitoring in case of remnant viable foci of tumor), the potential reduction of the number of RF procedures required to achieve complete necrosis and the complication rate of RF ablation procedure performed under MR temperature monitoring. In exploratory attempt, the study will include comparative assessment of these criteria with a historic leg of patients previously treated by the same operator in the same center for similar large tumor by multipolar RFA but using exclusively ultrasound monitoring.

The RF procedure and results assessment: 1. In preparing MR room, the patient will be positioned on MR bed put on dedicated MR compatible trolley. The abdominal antenna will be installed. 2. General anesthesia with tracheal intubation will be performed. 3. Up to six RF electrodes (up to 6 depending on the size and the location of the tumor) will be inserted under ultrasound guidance. 4. The patient will be translated without any direct manipulation in the magnet. 5. With usual T1 and T2 weighted MR morphologic sequences the poisoning of electrode will be checked and if necessary adjusted 6. Adjustment or MR temperature imaging (before RF energy deposition) 7. Starting of RF procedure under MR temperature monitoring 8. According to thermal dose maps data repositioning of electrodes and complementary energy deposition if necessary 9. Hot withdrawal of electrodes 10. Immediate (T0) post procedure MR assessment of the limits of ablation zone (T2 SPIRCHOL, Diffusion B600, In out phase, THRIVE dynamic after intravenous gadolinium injection). After the procedure patients will be monitored at least 48 h. MR assessment of treatment response will be performed one month after the procedure (same MR protocol performed at T0). If the ablation is complete follow up will be ensured by MR every three months. If the ablation appeared incomplete or in case of recurrence additional RF ablation will be performed if the patient stills met the criteria of the treatment. The eventual additional RF ablation will be performed under ultrasound monitoring (the response to each additional RF ablation procedure will be assessed by MR one month after). At the end of the study patients for whom complete radiological response of the tumor(s) initially treated (not local or distance recurrences) will be never achieved, will be considered in treatment failure. Local recurrence is defined as the reappearance of viable tumor in contact of ablation zone of a tumor considered at least on one MR post therapeutic examination as completely ablated. All the adverse effect and complication will be recorded and reported. Quantitative analysis of 2D and 3D parameters of tumors and their related ablation zones as observed at the end of RF procedures on temperature maps using thermal dose concept (as previously extensively investigated) and with usual morphologic MR imaging (all used sequences) before, during and after the procedure (one month after) will be recorded and compared. Antibioprophylaxy: will be prescribed in patients with an antecedent of endoscopic sphincterotomy (according to the CLIN protocol of Jean Verdier Hospital) and will be extended in patients : 1 older than 75 years , 2 patient with vesicular lithiasis 3) patients with nodule previously treated by embolization and those with a severe diabetes