title: Small hypervascular hepatocellular carcinoma: limited value of portal and delayed phases on dynamic magnetic resonance imaging.
abstract: BACKGROUND
  Characterization of small nodules in the cirrhotic liver is always challenging in clinical practice. In the differential diagnosis of small hypervascular lesions, it has been reported that portal venous or delayed hypointensity is a useful sign to characterize hepatocellular carcinomas (HCCs) during dynamic magnetic resonance (MR) imaging. However, few studies have assessed the diagnostic value of this sign.
  
  
  OBJECTIVE
  To determine the diagnostic value of portal-phase (PP) and delayed-phase (DP) images for the diagnosis of small hypervascular HCCs during intravenous (IV) contrast-enhanced dynamic MR imaging of cirrhotic liver.
  
  
  METHODS
  A total of 69 small (6-20 mm) hypervascular HCCs in 53 cirrhotic patients were subjected to a retrospective analysis of the signal intensities (hypo-, iso-, or hyperintense) and rim enhancement on PP and 5-min DP images from three-phased dynamic MR imaging according to the pre-contrast T1- and T2-weighted imaging features. After exclusion of 33 subcapsular wedge-shaped pseudolesions and three hemangiomas by typical imaging features, 74 centrally located small hypervascular benign or pseudolesions were used as a control group for comparative analyses.
  
  
  RESULTS
  The sensitivities of PP hypointensity, DP hypointensity, and rim enhancement in the diagnosis were 11%, 29%, and 18%, respectively, for 6-10-mm hypervascular HCCs, and 42%, 63%, and 58%, respectively, for 16-20-mm lesions. After exclusion of the 48 lesions showing T2-weighted hyperintensity (HCCs, n = 39; benign lesions, n = 9), the overall sensitivity for diagnosis of small hypervascular HCCs decreased (8.3%, 25.0%, and 8.3%, respectively).
  
  
  CONCLUSIONS
  Although DP provides a better sensitivity than PP, both PP and DP have very limited diagnostic value for diagnosis of small hypervascular HCCs during dynamic MR imaging of the cirrhotic liver.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, YongDong Severance Hospital, Seoul, Republic of Korea. yjsrad97@yuhs.ac
authors.forename: J S
authors.initials: JS
authors.lastname: Yu
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: J J
authors.initials: JJ
authors.lastname: Chung
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000098:blood supply* / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008103:Liver Cirrhosis / Q000150:complications; D008113:Liver Neoplasms / Q000098:blood supply* / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA