title: Comparison of MRI features for the differentiation of hepatic angiomyolipoma from fat-containing hepatocellular carcinoma.
abstract: OBJECTIVE
  The purpose of this study was to evaluate MRI features for the differentiation of hepatic angiomyolipoma (HAML) from fat-containing hepatocellular carcinoma.
  
  
  METHODS
  We retrospectively reviewed the MRI findings of 20 patients with 22 hepatic angiomyolipomas and 25 patients with fat-containing hepatocellular carcinomas before surgery. The MRI features and apparent diffusion coefficient (ADC) for the two types of tumors were compared and analyzed.
  
  
  RESULTS
  Fat was not detected in nine (40.9%) of the angiomyolipomas. An enhancement pattern of the washout area was seen in eight (36.4%) of the angiomyolipomas and 21 of the hepatocellular carcinomas (84%) (p = 0.001). The sensitivity, specificity, and accuracy of the enhancement pattern for HAML were 63.6% (14/22), 84% (21/25), and 74.5% (35/47), respectively. An early draining vein was seen in 16 (72.7%) angiomyolipomas and two hepatocellular carcinomas (8%) (p < 0.001). The sensitivity, specificity, and accuracy of an early draining vein for detecting HAML was 72.7% (16/22), 92% (23/25), and 83.0% (39/47), respectively. Tumor vessels were noted in 18 (81.8%) angiomyolipomas and six hepatocellular carcinomas (24%) (p < 0.001). The sensitivity, specificity, and accuracy of tumor vessels for HAML were 81.8% (18/22), 76% (19/25), and 78.7% (37/47), respectively. Pseudocapsules were absent in 21 (95.5%) angiomyolipomas as compared with 3 (12%) hepatocellular carcinomas (p < 0.001). The sensitivity, specificity, and accuracy of pseudocapsules for HAML were 95.5% (21/22), 88% (22/25), and 91.5% (43/47), respectively. The ADC of the angiomyolipomas (1.92 ± 0.29 × 10(-3 )mm(2)/s) was significantly higher than that for hepatocellular carcinomas (1.33 ± 0.25 × 10(-3 )mm(2)/s) (p < 0.001).
  
  
  CONCLUSIONS
  The presence of an early draining vein and tumor vessels, the absence of pseudocapsules and a higher ADC in the hypervascular hepatic tumor on the MRI were helpful for the differentiation of hepatic angiomyolipoma from fat-containing hepatocellular carcinoma.
authors.affiliation: Department of Radiology, Changshu Second People's Hospital, Changshu, Jiangsu, 215500, China.
authors.forename: Sheng-yu
authors.initials: SY
authors.lastname: Wang
authors.forename: Xin-ping
authors.initials: XP
authors.lastname: Kuai
authors.forename: Xiao-xi
authors.initials: XX
authors.lastname: Meng
authors.forename: Ning-yang
authors.initials: NY
authors.lastname: Jia
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
mesh_terms: D000328:Adult; D000368:Aged; D018207:Angiomyolipoma / Q000473:pathology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA