title: Radiofrequency ablation for hepatocellular carcinoma abutting the diaphragm: comparison of effects of thermal protection and therapeutic efficacy.
abstract: OBJECTIVE
  This study was designed to assess the effect of artificial ascites on thermal protection of the diaphragm and the therapeutic efficacy of this technique during percutaneous radiofrequency ablation for hepatocellular carcinoma abutting the diaphragm.
  
  
  METHODS
  A total of 44 patients with a single nodular hepatocellular carcinoma (< 4 cm; mean, 2.2 cm) that abutted the diaphragm were treated with ultrasound-guided percutaneous radiofrequency ablation as first-line treatment. The patients were divided into two groups: a group who received artificial ascites (n = 20) and a control group (n = 24). We compared the two groups in an assessment for change in diaphragmatic thickness, right shoulder pain, and transient lung injury as indicators of thermal injury to the diaphragm. We evaluated therapeutic efficacy with follow-up CT.
  
  
  RESULTS
  Swelling of diaphragm at immediate follow-up CT was more severe in the control group (mean change in thickness, 0.56 mm versus 1.55 mm; p = 0.01). Right shoulder pain (n = 1 versus n = 7) and transient lung injury (n = 0 versus n = 6) occurred statistically significantly more often in the control group than the artificial ascites group, but pleural effusion did not (n = 13 versus n = 1). The technical success rate was higher in the artificial ascites group (100% versus 79%, p = 0.06). There was no significant difference in effectiveness rate of the primary technique (100% versus 92%, p = 0.49) or rate of local tumor progression (20% versus 30%, p = 0.47).
  
  
  CONCLUSIONS
  The use of artificial ascites for percutaneous radiofrequency ablation of hepatocellular carcinoma abutting the diaphragm had a significant effect on thermal protection of the diaphragm but not on therapeutic efficacy.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, Republic of Korea.
authors.forename: Tae Wook
authors.initials: TW
authors.lastname: Kang
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: Min Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Young-sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
mesh_terms: D000328:Adult; D000368:Aged; D001201:Ascites; D002056:Burns / Q000517:prevention & control; D006528:Carcinoma, Hepatocellular / Q000601:surgery*; D016022:Case-Control Studies; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D016009:Chi-Square Distribution; D003964:Diaphragm / Q000601:surgery*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional