title: Feasibility and reliability of the FibroScan S2 (pediatric) probe compared with the M probe for liver stiffness measurement in small adults with chronic liver disease.
abstract: BACKGROUND
  The success of liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is influenced by anthropometric factors. In smaller adults, the M probe may fail due to narrow intercostals spaces and rib interference. We aimed to compare LSM using the FibroScan S2 (pediatric) probe with the M probe in small adults with chronic liver disease.
  
  
  METHODS
  In this prospective study, 41 liver disease patients and 18 controls with a thoracic perimeter ≤ 75 cm underwent LSM using the FibroScan M and S2 probes. TE failure was defined as no valid LSMs and unreliable examinations as < 10 valid LSMs, an interquartile range (IQR)/LSM > 30%, or success rate < 60%.
  
  
  RESULTS
  TE failure was not observed and reliability did not differ between the M and S2 probes (86% vs. 95%; P = 0.20). Liver stiffness measured using the M and S2 probes was highly correlated (ρ = 0.81; P < 0.0005) and median liver stiffness did not differ between probes (4.5 vs. 4.4 kPa; P = 0.10). However, in participants with a skin-capsular distance ≥ 15 mm, median liver stiffness was higher using the S2 probe (5.5 vs. 4.9 kPa; P = 0.008). When compared with validated liver stiffness cut-offs, the S2 probe would have overestimated the stage of fibrosis compared with the M probe in 10% of patients.
  
  
  CONCLUSIONS
  The FibroScan S2 probe does not improve the feasibility of LSM in adults of smaller stature and may overestimate liver stiffness compared with the M probe. The FibroScan M probe should remain the preferred tool for LSM in small adults with chronic liver disease.
authors.affiliation: Liver Unit, Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Alberta, Canada T2N 4Z6.
authors.forename: Faruq
authors.initials: F
authors.lastname: Pradhan
authors.forename: Farah
authors.initials: F
authors.lastname: Ladak
authors.forename: Jenna
authors.initials: J
authors.lastname: Tracey
authors.forename: Pam
authors.initials: P
authors.lastname: Crotty
authors.forename: Robert P
authors.initials: RP
authors.lastname: Myers
mesh_terms: D000328:Adult; D049628:Body Size; D054459:Elasticity Imaging Techniques / Q000295:instrumentation*; D005240:Feasibility Studies; D005260:Female; D019694:Hepatitis B, Chronic / Q000150:complications / Q000000981:diagnostic imaging*; D019698:Hepatitis C, Chronic / Q000150:complications / Q000000981:diagnostic imaging*; D006519:Hepatitis, Alcoholic / Q000150:complications / Q000000981:diagnostic imaging*; D019693:Hepatitis, Autoimmune / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013909:Thorax / Q000033:anatomy & histology