title: Overcoming the heat-sink phenomenon: successful radiofrequency thermal ablation of liver tumors in contact with blood vessels.
abstract: OBJECTIVE
  To evaluate the efficacy and safety of computed tomography (CT)-guided radiofrequency thermal ablation (RFA) of liver tumors (hepatocellular carcinoma and liver metastases) > 3 mm in diameter that were in contact with blood vessels.
  
  
  METHODS
  During a 3-year period RFA was performed in 28 patients (age range, 36-83 years; male/female ratio, 17:11) with liver tumors (primary and metastatic) that were in contact with blood vessels > 3 mm in diameter. Tumor diameter ranged from 1.7 to 5.1 cm. To evaluate the immediate response, dual-phase dynamic CT images were obtained after intravenous contrast material administration. Imaging follow-up was at 1, 3, 6, and 12 months post-RFA, and every year thereafter.
  
  
  RESULTS
  All of 28 patients were treated with a total of 36 sessions. In 22 (79%) of the patients, complete ablation of the tumor was achieved. The remaining 6 (21%) patients showed irregular peripheral enhancement and underwent a second session. At 1-year follow-up 2 of the tumors showed a recurrent lesion and a new ablation was performed. The local tumor progression rate at 1-year follow-up was 8.7% and disease-free survival was achieved in 82.1% of the patients. Complications occurred in 4 patients (14.3%); 2 patients presented with a small sub-capsular hematoma, and 2 patients had a partial liver infarction.
  
  
  CONCLUSIONS
  RFA is a safe and effective method, even with high-risk tumors adjacent to large blood vessels, which can lead to good results with minimal complications and a low rate of tumor progression.
authors.affiliation: Department of Radiology, Sotiria Hospital, Athens, Greece. loutharad@yahoo.com
authors.forename: Loukas
authors.initials: L
authors.lastname: Thanos
authors.forename: Sophia
authors.initials: S
authors.lastname: Mylona
authors.forename: Panagiota
authors.initials: P
authors.lastname: Galani
authors.forename: Maria
authors.initials: M
authors.lastname: Pomoni
authors.forename: Anastasia
authors.initials: A
authors.lastname: Pomoni
authors.forename: Ioannis
authors.initials: I
authors.lastname: Koskinas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D006503:Hepatic Veins / Q000000981:diagnostic imaging; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011169:Portal Vein / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014421:Turkey; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging