title: Posterior acoustic enhancement in hepatocellular carcinoma.
abstract: OBJECTIVE
  The purpose of this study was to assess sonographic appearances of hepatocellular carcinoma with particular attention to posterior acoustic effects.
  
  
  METHODS
  We performed an Institutional Review Board-approved retrospective review of patients with hepatocellular carcinoma who had undergone sonographically guided procedures in our department between 2001 and 2010. A total of 247 masses thought to represent hepatocellular carcinoma were identified; 27 were excluded because of prior angioembolization (altering the sonographic appearance), alternate histologic diagnoses, and incomplete patient information or imaging. Ultimately, 220 masses in 185 patients (138 men and 47 women; average age, 59.1 years) constituted the study population. Preprocedure sonograms were reviewed in consensus by 3 abdominal radiologists; the liver echo texture, lesion echogenicity, and posterior acoustic effect were rated and correlated with patient data.
  
  
  RESULTS
  The average mass size was 3.1 cm (range, 0.7-17 cm). In total, 84.1% of the masses (n = 185) arose in abnormally echogenic/attenuating livers; 54.1% of the masses (n = 119) were predominantly hypoechoic, 23.2% (n = 51) isoechoic, and 22.7% (n = 50) hyperechoic. Target-type morphologic characteristics were noted in 41 masses. Many masses (52.7% [n = 116]) had no specific posterior acoustic effect, but nearly half (46.4%) had either mild (n = 64) or marked (n = 38) posterior acoustic enhancement. The remaining masses (0.9% [n = 2]) had posterior shadowing. Posterior acoustic enhancement was most common among hyperechoic masses (62% with posterior acoustic enhancement), target-type masses (63%), and masses larger than 5 cm (81.5%).
  
  
  CONCLUSIONS
  Posterior acoustic enhancement is present to some degree in almost half of hepatocellular carcinomas, which may relate to the tissue characteristics of the tumor or the cirrhotic liver itself. Attention to this finding, including scanning without spatial compounding, is recommended during sonographic screening for hepatocellular carcinoma in the growing population of patients with liver disease.
authors: Department of Radiology, University of Michigan Health System, Ann Arbor, MI 48109-5030, USA. kmaturen@umich.edu
authors: Katherine E
authors: KE
authors: Maturen
authors: Ashish P
authors: AP
authors: Wasnik
authors: Janet E
authors: JE
authors: Bailey
authors: Ellen G
authors: EG
authors: Higgins
authors: Jonathan M
authors: JM
authors: Rubin
mesh_terms: D000162:Acoustics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014463:Ultrasonography