title: Hepatic fibrosis: evaluation with semiquantitative contrast-enhanced CT.
abstract: OBJECTIVE
  To evaluate the feasibility of using contrast material-enhanced computed tomographic (CT) measurements of hepatic fractional extracellular space (fECS) and macromolecular contrast material (MMCM) uptake to measure severity of liver fibrosis.
  
  
  METHODS
  All procedures were approved by and executed in accordance with University of California, San Francisco, institutional animal care and use committee regulations. Twenty-one rats that received intragastric CCl(4) for 0-12 weeks were imaged with respiratory-gated micro-CT by using both a conventional contrast material and a novel iodinated MMCM. Histopathologic hepatic fibrosis was graded qualitatively by using the Ishak fibrosis score and quantitatively by using morphometry of the fibrosis area. Hepatic fECS and MMCM uptake were calculated for each examination and correlated with histopathologic findings by using uni- and multivariate linear regressions.
  
  
  RESULTS
  Ishak fibrosis scores ranged from a baseline of 0 in untreated animals to a maximum of 5. Histopathologic liver fibrosis area increased from 0.46% to 3.5% over the same interval. Strong correlations were seen between conventional contrast-enhanced CT measurements of fECS and both the Ishak fibrosis scores (R(2) = 0.751, P < .001) and the fibrosis area (R(2) = 0.801, P < .001). Strong negative correlations were observed between uptake of MMCM in the liver and Ishak fibrosis scores (R(2) = 0.827, P < .001), as well as between uptake of MMCM in the liver and fibrosis area (R(2) = 0.643, P = .001). Multivariate linear regression analysis showed a trend toward independence for fECS and MMCM uptake in the prediction of Ishak fibrosis scores, with an R(2) value of 0.86 (P = .081 and P = .033, respectively).
  
  
  CONCLUSIONS
  Contrast-enhanced CT measurements of fECS and MMCM uptake are individually capable of being used to estimate the degree of early hepatic fibrosis in a rat model.
  
  
  BACKGROUND
  http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112452/-/DC1.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Ave, Box 0628, M-372, San Francisco, CA 94143-0628, USA.
authors.forename: Vanja
authors.initials: V
authors.lastname: Varenika
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Fu
authors.forename: Jacquelyn J
authors.initials: JJ
authors.lastname: Maher
authors.forename: Dongwei
authors.initials: D
authors.lastname: Gao
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kakar
authors.forename: Miguel C
authors.initials: MC
authors.lastname: Cabarrus
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Yeh
mesh_terms: D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D005240:Feasibility Studies; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media