title: Planning ultrasound for percutaneous radiofrequency ablation to treat small (≤ 3 cm) hepatocellular carcinomas detected on computed tomography or magnetic resonance imaging: a multicenter prospective study to assess factors affecting ultrasound visibility.
abstract: OBJECTIVE
  To assess factors affecting tumor visibility on planning ultrasound (US) for percutaneous radiofrequency (RF) ablation to treat small hepatocellular carcinomas (HCCs) primarily detected on computed tomography (CT) or magnetic resonance (MR) imaging.
  
  
  METHODS
  Patients referred for planning US for percutaneous RF ablation between September 2008 and June 2009 were prospectively enrolled from nine institutions in Korea. The first small (≤ 3 cm) single HCC or new single HCC after treatment was included. The study enrolled 898 patients (684 men and 214 women, age range 32-86 years). HCCs that were invisible on planning US were compared with visible HCCs with respect to tumor size, distance between the tumor and the diaphragm, subcapsular location, etiology of liver disease, liver cirrhosis, macronodular cirrhosis on US, ascites, Child-Pugh class, serum alpha fetoprotein (AFP) level, body mass index (BMI), previous treatments for HCC, previous chemoembolization treatments for HCC, institutions, and experience of radiologists.
  
  
  RESULTS
  Among 898 HCCs, 671 (74.7%) were visible on the planning US. In multivariate analysis, tumor size, distance between the tumor and the diaphragm, liver cirrhosis, and macronodular cirrhosis were statistically significant factors affecting US detection (each P < .05).
  
  
  CONCLUSIONS
  Smaller tumors, subphrenic location of the tumor, liver cirrhosis, and macronodular cirrhosis were independent predictors of invisible tumors on planning US.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Pyo Nyun
authors.initials: PN
authors.lastname: Kim
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Rha
authors.forename: Hyun Pyo
authors.initials: HP
authors.lastname: Hong
authors.forename: Jongmee
authors.initials: J
authors.lastname: Lee
authors.forename: Joon-Il
authors.initials: JI
authors.lastname: Choi
authors.forename: Jin Woong
authors.initials: JW
authors.lastname: Kim
authors.forename: Jung Wook
authors.initials: JW
authors.lastname: Seo
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Lee
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation; D016009:Chi-Square Distribution; D002983:Clinical Competence; D003287:Contrast Media; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D056910:Republic of Korea; D012720:Severity of Illness Index; D047368:Tumor Burden; D018084:Ultrasonography, Interventional; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: C097353:AFP protein, human; D003287:Contrast Media; D000509:alpha-Fetoproteins