title: Quantification of hepatic iron concentration in chronic viral hepatitis: usefulness of T2-weighted single-shot spin-echo echo-planar MR imaging.
abstract: OBJECTIVE
  To investigate the usefulness of single-shot spin-echo echo-planar imaging (SSEPI) sequence for quantifying mild degree of hepatic iron stores in patients with viral hepatitis.
  
  
  METHODS
  This retrospective study included 34 patients with chronic viral hepatitis/cirrhosis who had undergone histological investigation and magnetic resonance imaging with T2-weighted gradient-recalled echo sequence (T2-GRE) and diffusion-weighted SSEPI sequence with b-factors of 0 s/mm(2) (T2-EPI), 500 s/mm(2) (DW-EPI-500), and 1000 s/mm(2) (DW-EPI-1000). The correlation between the liver-to-muscle signal intensity ratio, which was generated by regions of interest placed in the liver and paraspinous muscles of each sequence image, and the hepatic iron concentration (µmol/g dry liver), which was assessed by spectrophotometry, was analyzed by linear regression using a spline model. Akaike information criterion (AIC) was used to select the optimal model.
  
  
  RESULTS
  Mean ± standard deviation of the hepatic iron concentration quantified by spectrophotometry was 24.6 ± 16.4 (range, 5.5 to 83.2) µmol/g dry liver. DW-EPI correlated more closely with hepatic iron concentration than T2-GRE (R square values: 0.75 for T2-EPI, 0.69 for DW-EPI-500, 0.62 for DW-EPI-1000, and 0.61 for T2-GRE, respectively, all P<0.0001). Using the AIC, the regression model for T2-EPI generated by spline model was optimal because of lowest cross validation error.
  
  
  CONCLUSIONS
  T2-EPI was sensitive to hepatic iron, and might be a more useful sequence for quantifying mild degree of hepatic iron stores in patients with chronic viral hepatitis.
authors.affiliation: Department of Radiology, Kurume University School of Medicine, Kurume, Fukuoka, Japan [corrected].
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Tonan
authors.forename: Kiminori
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Aliya
authors.initials: A
authors.lastname: Qayyum
authors.forename: Takumi
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawaguchi
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakashima
authors.forename: Koji
authors.initials: K
authors.lastname: Okuda
authors.forename: Naofumi
authors.initials: N
authors.lastname: Hayabuchi
authors.forename: Michio
authors.initials: M
authors.lastname: Sata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D017352:Echo-Planar Imaging / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006525:Hepatitis, Viral, Human / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007501:Iron / Q000032:analysis / Q000378:metabolism*; D016014:Linear Models; D008099:Liver / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012189:Retrospective Studies; D013053:Spectrophotometry / Q000706:statistics & numerical data
chemical_list: D007501:Iron