title: Multipolar hepatic radiofrequency ablation using up to six applicators: preliminary results.
abstract: OBJECTIVE
  To evaluate the clinical feasibility and safety of hepatic radiofrequency (RF) ablation using a multipolar RF system permitting the simultaneous use of up to six electrodes.
  
  
  METHODS
  Ten patients (3 female, 7 male, mean age 61) suffering from 29 hepatic metastases (range: 1 - 5) of different tumors were treated with a modified multipolar RF system (CelonLab Power, Celon Medical Instruments, Teltow, Germany) operating four to six needle-shaped internally cooled RF applicators. The procedure duration, applied energy and generator output were recorded during the intervention. The treatment result and procedure-related complications were analyzed. The achieved coagulation volume was calculated on the basis of contrast-enhanced CT scans 24 hours after RF ablation.
  
  
  RESULTS
  Complete tumor ablation was achieved in all cases as determined by the post-interventional lack of contrast enhancement in the target region using four applicators in five patients, five applicators in one patient and six applicators in four patients. A mean energy deposition of 353.9 +/- 176.2 kJ resulted in a mean coagulation volume of 115.9 +/- 79.5 cm (3). The mean procedure duration was 74.9 +/- 21.2 minutes. Four patients showed an intraabdominal hemorrhage which necessitated further interventional treatment (embolization; percutaneous histoacryl injection) in two patients.
  
  
  CONCLUSIONS
  Multipolar RF ablation of hepatic metastasis with up to six applicators was clinically feasible. In our patient population it was associated with an increased risk of intraabdominal bleeding probably due to the multiple punctures associated with the use of multiple applicators.
authors.affiliation: Lehrstuhl für Angewandte Medizintechnik, Helmholtz Institut für Biomedizinische Technik, RWTH Aachen, Pauwelsstrasse 20, Aachen. bruners@hia.rwth-aachen.de
authors.forename: P
authors.initials: P
authors.lastname: Bruners
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: R W
authors.initials: RW
authors.lastname: Günther
authors.forename: A
authors.initials: A
authors.lastname: Mahnken
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation*; D015179:Colorectal Neoplasms; D016001:Confidence Intervals; D004566:Electrodes; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015641:Radiography, Interventional; D012086:Reoperation; D012307:Risk Factors; D013274:Stomach Neoplasms; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome