title: Utility of non-contrast-enhanced CT for improved detection of arterial phase hyperenhancement in hepatocellular carcinoma.
abstract: OBJECTIVE
  To determine the utility of non-contrast-enhanced CT (NC-CT) for improved detection of hyperenhancement in hepatocellular carcinomas (HCC).
  
  
  METHODS
  We performed a retrospective analysis on CT studies of 104 consecutive patients with 124 HCCs between October 2006 and December 2012. The enhancement of HCC was evaluated on quadriphasic CT: non-contrast (NC), arterial phase (AP), portal-venous phase (PVP), and delayed phases (DP) were performed. For determination of enhancement, mean attenuation of the HCC and surrounding non-tumor bearing liver in the four phases were recorded. Hyperenhancement was defined by either HCC (AP-NC) representing absolute lesion enhancement or AP (HCC-liver), representing relative enhancement. An increase of ≥10 Hounsfield units (HU) was considered as enhancement. Two radiologists (R1 and R2) independently performed a conventional qualitative assessment for hyperenhancement of HCC. The accuracy of detection by proposed absolute lesion enhancement HCC (AP-NC) was compared to relative enhancement AP (HCC-liver) and qualitative assessment by readers with the McNemar test.
  
  
  RESULTS
  The proposed criteria of absolute lesion enhancement, HCC (AP-NC) identified more hypervascular nodules compared to qualitative analysis (92% vs. 62% for R1 and 69% for R2), equating to an improvement of 23%-31%. In contrast, relative enhancement AP (HCC-liver) was found to be inferior to conventional qualitative analysis (50% vs. 62%-69% for readers).
  
  
  CONCLUSIONS
  NC-CT is useful to improve the detection of hyperenhancement in HCCs for imaging diagnosis.
authors.affiliation: Department of Diagnostic Imaging, National University Hospital, Singapore, Singapore.
authors.forename: Tiffany
authors.initials: T
authors.lastname: Hennedige
authors.forename: Zhineng Jayson
authors.initials: ZJ
authors.lastname: Yang
authors.forename: Cheng Kang
authors.initials: CK
authors.lastname: Ong
authors.forename: Sudhakar Kundapur
authors.initials: SK
authors.lastname: Venkatesh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult