title: Normal liver elasticity values using acoustic radiation force impulse imaging: a prospective study in healthy living liver and kidney donors.
abstract: OBJECTIVE
  Although several studies have investigated the normal range of liver elasticity using acoustic radiation force impulse (ARFI) elastography in healthy volunteers, they could not strictly exclude the morphological and functional liver abnormalities. The aim of this study was to identify the normal range of ARFI velocity by recruiting healthy living liver and kidney donors who passed the full laboratory tests and imaging studies.
  
  
  METHODS
  The study prospectively enrolled 108 healthy living liver (n = 42) and kidney donors (n = 66) who were admitted for transplantation between July 2010 to April 2011. None of the subjects had abnormal liver function test and imaging findings including conventional ultrasonography, computed tomography or magnetic resonance imaging.
  
  
  RESULTS
  The mean age of the study population (58 men and 50 women) was 35.5 years, and the mean ARFI velocity was 1.07 ± 0.11 m/s (range: 0.79-1.27). ARFI velocity was not significantly different between subjects with body mass index (BMI) < 23.5 kg/m(2) and those with BMI ≥ 23.5 kg/m(2) (1.05 ± 0.12 m/s vs 1.07 ± 0.10 m/s, P = 0.518), nor was it significantly different according to age (P = 0.067) and gender (1.08 ± 0.12 m/s for men vs 1.05 ± 0.11 m/s for women, P = 0.085). Using the 5(th) and 95(th) percentiles, we determined the normal range and mean of ARFI velocity to be 0.85-1.25 m/s and 1.07 ± 0.11 m/s.
  
  
  CONCLUSIONS
  We identified the normal range of ARFI velocity as 0.85-1.25 m/s and found that it was not significantly influenced by BMI, gender, and age.
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chang Young
authors.initials: CY
authors.lastname: Son
authors.forename: Seung Up
authors.initials: SU
authors.lastname: Kim
authors.forename: Woong Kyu
authors.initials: WK
authors.lastname: Han
authors.forename: Gi Hong
authors.initials: GH
authors.lastname: Choi
authors.forename: Hana
authors.initials: H
authors.lastname: Park
authors.forename: Seung Choul
authors.initials: SC
authors.lastname: Yang
authors.forename: Jin Sub
authors.initials: JS
authors.lastname: Choi
authors.forename: Jun Yong
authors.initials: JY
authors.lastname: Park
authors.forename: Do Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Ahn
authors.forename: Chae Yoon
authors.initials: CY
authors.lastname: Chon
authors.forename: Kwang-Hyub
authors.initials: KH
authors.lastname: Han
mesh_terms: D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D015992:Body Mass Index; D016009:Chi-Square Distribution; D054459:Elasticity Imaging Techniques; D005260:Female; D006801:Humans; D007668:Kidney / Q000033:anatomy & histology*; D016030:Kidney Transplantation; D008099:Liver / Q000033:anatomy & histology*; D016031:Liver Transplantation; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D056910:Republic of Korea; D012737:Sex Factors; D055815:Young Adult