title: MR-guided radiofrequency ablation in a 0.2-T open MR system: technical success and technique effectiveness in 100 liver tumors.
abstract: OBJECTIVE
  To evaluate the feasibility and technique effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatic malignancies.
  
  
  METHODS
  In 64 patients, 100 primary (N = 19) or secondary (N = 81) liver tumors (mean diameter = 24.7 mm; range = 4-60 mm) were treated with 87 sessions of MR-guided RF ablation. The entire ablation procedure was carried out at an 0.2-T open MR system by using MR-compatible internally cooled electrodes. T2-weighted turbo spin echo sequences (TR/TE = 3500 msec/110 msec) were used to monitor thermally induced coagulation. Technique effectiveness was assessed four months after the last RF ablation by dynamic MR imaging at 1.5-T.
  
  
  RESULTS
  MR-guided RF ablation procedures were technical successful in 85 of 87 (97.7%) assessed at the end of each session. Complete coagulation was intended in 99 of 100 tumors. Technique effectiveness was observed in 92 of 99 (92.9%) of these tumors. To achieve complete coagulation 82 of 92 (89.1%) tumors required a single session. T2-weighted sequences were accurate to monitor the extent of coagulation and were supportive to guide overlapping ablation. There were two of 87 (2.3%) major and seven of 87 (8.0%) minor complications.
  
  
  CONCLUSIONS
  MR-guided RF ablation is a safe and effective therapy in the treatment of hepatic malignancies. MR imaging offers an accurate monitoring of thermally-induced coagulation, thus enabling complete tumor coagulation in a single session.
authors: Department of Diagnostic Radiology, University Hospital, Eberhard-Karls-University, Tübingen, Germany. stephen.clasen@med.uni-tuebingen.de
authors: Stephan
authors: S
authors: Clasen
authors: Andreas
authors: A
authors: Boss
authors: Diethard
authors: D
authors: Schmidt
authors: Christina
authors: C
authors: Schraml
authors: Jan
authors: J
authors: Fritz
authors: Fritz
authors: F
authors: Schick
authors: Claus D
authors: CD
authors: Claussen
authors: Philippe L
authors: PL
authors: Pereira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D015203:Reproducibility of Results