title: Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study.
abstract: To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin.
  
  
  
  In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25-35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10-26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications.
  
  
  
  Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3-12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21-1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients.
  
  
  
  Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Sung Il
authors: SI
authors: Park
authors: Department of Radiology, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon 14647, Korea.
authors: Il Jung
authors: IJ
authors: Kim
authors: Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam 13496, Korea.
authors: Shin Jae
authors: SJ
authors: Lee
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Min Woo
authors: MW
authors: Shin
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Won Sun
authors: WS
authors: Shin
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Yong Eun
authors: YE
authors: Chung
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Gyoung Min
authors: GM
authors: Kim
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Man Deuk
authors: MD
authors: Kim
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Jong Yun
authors: JY
authors: Won
authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Do Yun
authors: do Y
authors: Lee
authors: Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Jin Sub
authors: JS
authors: Choi
authors: Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea.
authors: Kwang-Hyub
authors: KH
authors: Han
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: Angled electrode; Hepatoma; Metastasis; Radiofrequency ablation; Subcapsular; Superficial; Technique