title: Factors associated with the impossibility to obtain reliable liver stiffness measurements by means of Acoustic Radiation Force Impulse (ARFI) elastography--analysis of a cohort of 1,031 subjects.
abstract: BACKGROUND
  Acoustic Radiation Force Impulse (ARFI) elastography is a non-invasive technique for liver fibrosis assessment.
  
  
  OBJECTIVE
  To assess the feasibility of ARFI elastography in a large cohort of subjects and to identify factors associated with impossibility to obtain reliable liver stiffness (LS) measurements by means of this technique.
  
  
  METHODS
  Our retrospective study included 1031 adult subjects with or without chronic liver disease. In each subject LS was assessed by means of ARFI elastography. Failure of ARFI measurements was defined if no valid measurement was obtained after at least 10 shots and unreliable in the following situations: fewer than 10 valid shots; or median value of 10 valid measurements with a success rate (SR)<60% and/or an interquartile range interval (IQR) ≥ 30%.
  
  
  RESULTS
  Failure of LS measurements by means of ARFI was observed in 4 subjects (0.3%), unreliable measurements in 66 subjects (6.4%), so reliable measurements were obtained in 961 subjects (93.3%). In univariant analysis, the following risk factors were associated with failed and unreliable measurements: age over 58 years (OR=0.49; 95% CI 0.30-0.80, p=0.005), male gender (OR=0.58; 95% CI 0.34-0.94, p=0.04), BMI>27.7 kg/m(2) (OR=0.23, 95% CI 0.13-0.41, p<0.0001). In multivariate analysis all the factors mentioned above were independently associated with the risk of failed and unreliable measurements.
  
  
  CONCLUSIONS
  Reliable LS measurements by means of ARFI elastography were obtained in 93.3% of cases. Older age, higher BMI and male gender were associated with the risk of failed and unreliable measurements, but their influence is limited as compared with Transient Elastography.
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: bota_simona1982@yahoo.com.
authors.forename: Simona
authors.initials: S
authors.lastname: Bota
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: isporea@umft.ro.
authors.forename: Ioan
authors.initials: I
authors.lastname: Sporea
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: roxanasirli@gmail.com.
authors.forename: Roxana
authors.initials: R
authors.lastname: Sirli
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: alinamircea.popescu@gmail.com.
authors.forename: Alina
authors.initials: A
authors.lastname: Popescu
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: mireladanila@gmail.com.
authors.forename: Mirela
authors.initials: M
authors.lastname: Danila
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: ana.jurchis@yahoo.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Jurchis
authors.affiliation: Department of Gastroenterology and Hepatology, "Victor Babes" University of Medicine and Pharmacy Timisoara, Romania. Electronic address: bluonmyown@yahoo.com.
authors.forename: Oana
authors.initials: O
authors.lastname: Gradinaru-Tascau
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008107:Liver Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D055815:Young Adult
keywords: ARFI elastography; Failed measurements; Liver fibrosis; Liver stiffness; Reliable measurements; Unreliable measurements