title: Impact of skin capsular distance on the performance of controlled attenuation parameter in patients with chronic liver disease.
abstract: OBJECTIVE
  Controlled attenuation parameter (CAP) is a non-invasive method for evaluating hepatic steatosis. However, larger skin capsular distance (SCD) can affect the accuracy. The aim of this study was to investigate the impact of SCD on the diagnostic performance of CAP and liver stiffness measurement (LSM).
  
  
  METHODS
  Of 101 patients with non-alcoholic fatty liver disease (NAFLD) and 280 patients with chronic hepatitis B (CHB) who underwent liver biopsy were prospectively recruited. CAP, LSM and SCD were performed using FibroScan with M probe. The areas under receiver operating characteristics curves (AUROCs) were calculated to determine the diagnostic efficacy. The optimal thresholds were defined by the maximum Youden index.
  
  
  RESULTS
  SCD (B 30.34, P < 0.001) and hepatic steatosis (B 23.04, P < 0.001) were independently associated with CAP by multivariate analysis. The AUROCs were slightly higher for SCD <25 mm compared to those for SCD ≥25 mm for steatosis ≥5% (0.88 vs. 0.81), >33% (0.90 vs. 0.85) and >66% (0.84 vs. 0.72). For SCD <25 mm, the optimal CAP cut-offs for differentiating steatosis ≥5%, >33% and >66% were 255.0 dB/m, 283.5 dB/m and 293.5 dB/m. However, cut-offs were elevated by approximately 60-70 dB/m for SCD ≥25 mm. When stratified by fibrosis grade, LSM was significantly affected by SCD ≥25 mm for advanced fibrosis (≥F3) in NAFLD, but not in CHB.
  
  
  CONCLUSIONS
  CAP is a promising tool for detecting and quantifying hepatic steatosis. SCD ≥25 mm may cause overestimation of steatosis. Similarly, SCD ≥25 mm affects the detection of advanced fibrosis by LSM in NAFLD patients.
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shen
authors.affiliation: Research and Therapy Centre for Liver Disease, Zhengxing Hospital, Zhangzhou, China.
authors.forename: Rui-Dan
authors.initials: RD
authors.lastname: Zheng
authors.affiliation: Department of Liver Diseases, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Shi
authors.affiliation: Research Institute of Liver Diseases, Tianjin Second People's Hospital, Tianjin, China.
authors.forename: Yu-Qiang
authors.initials: YQ
authors.lastname: Mi
authors.affiliation: Centre for Liver Fibrosis Treatment Unit, 302 Military Hospital, Beijing, China.
authors.forename: Guo-Feng
authors.initials: GF
authors.lastname: Chen
authors.affiliation: Department of Pathology, Shanghai Medical College of Fudan University, Shanghai, China.
authors.forename: Xiqi
authors.initials: X
authors.lastname: Hu
authors.affiliation: Research Institute of Liver Diseases, Tianjin Second People's Hospital, Tianjin, China.
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Liu
authors.affiliation: Department of Pathology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Pan
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Chen
authors.affiliation: Research and Therapy Centre for Liver Disease, Zhengxing Hospital, Zhangzhou, China.
authors.forename: Jian-Neng
authors.initials: JN
authors.lastname: Chen
authors.affiliation: Research Institute of Liver Diseases, Tianjin Second People's Hospital, Tianjin, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Rui-Nan
authors.initials: RN
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Lei-Ming
authors.initials: LM
authors.lastname: Xu
authors.affiliation: Department of Gastroenterology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Jian-Gao
authors.initials: JG
authors.lastname: Fan
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001706:Biopsy; D015992:Body Mass Index; D002681:China; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D019694:Hepatitis B, Chronic / Q000473:pathology*; D006801:Humans; D008099:Liver / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D065626:Non-alcoholic Fatty Liver Disease / Q000473:pathology*; D011446:Prospective Studies; D012372:ROC Curve; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology*
keywords: controlled attenuation parameter; liver stiffness; non-alcoholic fatty liver disease; skin capsular distance; transient elastography