title: Noninvasive quantitative estimation of hepatic steatosis by ultrasound: a comparison of the hepato-renal index and ultrasound attenuation index.
abstract: OBJECTIVE
  To compare the accuracy of the ultrasound attenuation index (USAI) and hepato-renal index (HRI) for the diagnosis of hepatic steatosis (HS).
  
  
  METHODS
  Two hundred and twenty-four potential living hepatic donors underwent US and subsequent US-guided liver biopsy. The USAI was calculated from US images with an 8 MHz transducer and HRI was measured on sagittal images with a clear visualization of both the liver and kidney. Using histological degrees of HS as the reference standard, we compared the performance of USAI and HRI for diagnosing HS ≥ 5% and ≥ 30% by receiver operating characteristic curve analysis. The interobserver agreement was evaluated by using intraclass correlation coefficients (ICCs) or Bland-Altman statistics.
  
  
  RESULTS
  Histologic degree of HS was 0-70% (median, 5%). HRI showed a tendency towards higher accuracy than USAI for diagnosing HS ≥ 5% (the area under the ROC curve, 0.856 vs. 0.820; p= 0.279) and ≥ 30% (0.937 vs. 0.909; p = 0.378) without statistical significance. There was an excellent interobserver agreement for both USAI and HRI (ICC = 0.931 and 0.973, respectively). According to the Bland-Altman method, the 95% limits of difference between two readers for HS were -8.5% to 6.6% by USAI and -4.8% to 6.2% by HRI. Most patients would have the difference of calculated HS by USAI (74.0%) and HRI (96.0%) from different operators within a range of ±5%.
  
  
  CONCLUSIONS
  Although statistically insignificant, HRI was superior to USAI for the diagnosis and quantitative estimation of HS in terms of diagnostic performance, including accuracy and reproducibility.
authors.affiliation: Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Heon-Ju
authors.initials: HJ
authors.lastname: Kwon
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. kimkw@amc.seoul.kr.
authors.forename: Kyoung Won
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Dongguk University Ilsan Medical Center, Gyeonggi-do, Korea.
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Woo Kyoung
authors.initials: WK
authors.lastname: Jeong
authors.affiliation: Department of Radiology, Ajou University Medical Center, Gyeonggi-do, Korea.
authors.forename: Bohyun
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Liver Transplantation Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Gi-Won
authors.initials: GW
authors.lastname: Song
authors.affiliation: Department of Liver Transplantation Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sung-Gyu
authors.initials: SG
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging*; D008111:Liver Function Tests / Q000379:methods; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult