title: Characterization of hepatic lesions (≤ 30 mm) with liver-specific contrast agents: a comparison between ultrasound and magnetic resonance imaging.
abstract: OBJECTIVE
  Imaging-based differentiation of hepatic lesions (≤ 30 mm) between well-differentiated hepatocellular carcinomas (w-HCC) and regenerative nodules (RN) presents difficulties. The aim was to compare the diagnostic abilities to differentiate w-HCC from RN using contrast-enhanced ultrasound and magnetic resonance imaging (MRI) both with liver-specific contrast agents.
  
  
  METHODS
  This prospective study included 67 pathologically proven hepatic lesions (17.5 ± 5.4mm, 54 w-HCCs, 13 RNs) in 56 patients with chronic hepatitis/cirrhosis (male 40, female 16; 29-79y). Hepatic-arterial/liver-specific phase enhancements were assessed quantitatively by ultrasound with perflubutane microbubble agent and MRI with gadolinium-ethoxybenzyl-diethylenetriamine with respect to the histological findings.
  
  
  RESULTS
  Sensitivity, specificity and accuracy of hepatic-arterial phase hyper-enhancement for w-HCC were 59.3%, 100% and 67.2% by ultrasound and 46.3%, 100% and 56.7% by MRI without significant difference. Meanwhile, those of liver-specific-phase hypo-enhancement for w-HCC were 44.4%, 100% and 55.2% by ultrasound and 87.0% (p<0.0001), 46.2% (p=0.0052) and 79.1% (p=0.0032) by MRI. Diagnostic accuracies for w-HCC by area under the receiver operating characteristic curves were higher in the hepatic-arterial phase in ultrasound (0.8316) than MRI (0.6659, p=0.0101) and similar in the liver-specific phase in ultrasound (0.7225) and MRI (0.7347, p=0.8814).
  
  
  CONCLUSIONS
  Hypervascularity is a significant feature which distinguishes w-HCC from RN, and ultrasound exerts a beneficial impact better than MRI for such characterization. However, both imaging have comparable abilities in the characterization of non-hypervascular lesions, compensating mutually for the poor sensitivity of ultrasound and the poor specificity of MRI in the liver-specific phase.
authors.affiliation: Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. machat1215@yahoo.co.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Takahashi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Maruyama
authors.forename: Taro
authors.initials: T
authors.lastname: Shimada
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Kamezaki
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sekimoto
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kanai
authors.forename: Osamu
authors.initials: O
authors.lastname: Yokosuka
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D005466:Fluorocarbons; D019786:Gadolinium DTPA; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA; C108042:perfluorobutane