title: Hepatic computed tomography perfusion: comparison of maximum slope and dual-input single-compartment methods.
abstract: OBJECTIVE
  The aim of the study was to compare two analytical methods-maximum slope (MS) and the dualinput single-compartment model (CM)-in computed tomography (CT) measurements of hepatic perfusion and to assess the effects of extrahepatic systemic factors.
  
  
  METHODS
  A total of 109 patients underwent hepatic CT perfusion. The scans were conducted at the hepatic hilum 7-77 s after administration of contrast material. Hepatic arterial perfusion (HAP) and portal perfusion (HPP) (ml/min/100 ml) and the arterial perfusion fraction (APF, %) were calculated with the two methods, followed by correlation assessment. Partial correlation analysis was used to assess the effects on hepatic perfusion values by various factors, including age, sex, risk of cardiovascular disease, compensation for respiratory misregistration, arrival time of contrast material at the abdominal aorta, transit time from abdominal aorta to hepatic parenchyma, and liver dysfunction.
  
  
  RESULTS
  The mean HAPs, HPPs, and APFs were, respectively, 31.4, 104.2, and 23.9 for MS and 27.1, 141.3, and 22.1 for CM. HAP and APF showed significant (P<0.0001) and moderate correlation (γ=0.417 and 0.548) and HPP showed poor correlation (γ=0.172) between the two methods. While MS showed weak correlations (γ=-0.39 to 0.34; P<0.001 to <0.02) between multiple extrahepatic factors and perfusion values, CM showed weak correlation only between the patients' sex and HAP (γ=0.31, P=0.001).
  
  
  CONCLUSIONS
  Hepatic perfusion values estimated by the two methods are not interchangeable. CM is less susceptible to extrahepatic systemic factors.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuo-ku, Kobe, 650-0017, Japan. tkanda@med.kobe-u.ac.jp
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kanda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Naoki
authors.initials: N
authors.lastname: Kanata
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.forename: Munenobu
authors.initials: M
authors.lastname: Nogami
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takenaka
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000368:Aged; D003287:Contrast Media; D005260:Female; D006391:Hemangioma / Q000000981:diagnostic imaging*; D006801:Humans; D007479:Iopamidol; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D008107:Liver Diseases / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008962:Models, Theoretical; D011856:Radiographic Image Enhancement / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol