title: Pathophysiological analysis of nonalcoholic fatty liver disease by evaluation of fatty liver changes and blood flow using xenon computed tomography: can early-stage nonalcoholic steatohepatitis be distinguished from simple steatosis?
abstract: BACKGROUND
  Effective noninvasive tests that can distinguish early-stage nonalcoholic steatohepatitis (NASH) from simple steatosis (SS) have long been sought. Our aim was to determine the possibility of noninvasively distinguishing early-stage NASH from SS.
  
  
  METHODS
  We used Fick's principle and the Kety-Schmidt equation to determine the hepatic tissue blood flow (TBF) in 65 NASH patients who underwent xenon computed tomography (Xe-CT). We calculated the lambda value (LV), i.e., Xe gas solubility coefficient, in liver and blood. We assessed the histological severity of fatty changes and fibrosis on the basis of Brunt's classification. Liver biopsy revealed SS in 9 patients and NASH in 56 patients. NASH stages 1 and 2 were classified as early-stage NASH (Ea-NASH; 38 patients) and stages 3 and 4 as advanced-stage NASH (Ad-NASH; 18 patients). We evaluated the differences in LV and TBF among the 3 groups.
  
  
  RESULTS
  LV was significantly lower in the Ad-NASH group than in the SS and Ea-NASH groups. Portal venous TBF (PVTBF) was significantly lower in the Ea-NASH group than in the SS group, and PVTBF was lower in the Ad-NASH group than in the Ea-NASH group. Total hepatic TBF (THTBF) was significantly different between the SS and Ea-NASH groups and between the SS and Ad-NASH groups.
  
  
  CONCLUSIONS
  In conclusion, measurements of TBF and LV are useful for evaluating the pathophysiological progression of NASH. In addition, these measurements can facilitate the differential diagnosis of SS and Ea-NASH, which may not be distinguishable by other means.
authors.affiliation: Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Shigefuku
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Minoru
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ikeda
authors.forename: Kotaro
authors.initials: K
authors.lastname: Matsunaga
authors.forename: Chiaki
authors.initials: C
authors.lastname: Okuse
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Shiro
authors.initials: S
authors.lastname: Maeyama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sase
authors.forename: Michihiro
authors.initials: M
authors.lastname: Suzuki
authors.forename: Fumio
authors.initials: F
authors.lastname: Itoh
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005234:Fatty Liver / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008099:Liver / Q000098:blood supply / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D012995:Solubility; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon / Q000737:chemistry; D055815:Young Adult
chemical_list: D014978:Xenon