title: Significant variations in elastometry measurements made within short-term in patients with chronic liver diseases.
abstract: OBJECTIVE
  Transient elastometry is a noninvasive procedure used to measure fibrosis when patients are diagnosed with liver disease; it might be used to monitor changes over time. We investigated whether there are short-term variations in stiffness measurements that are not attributable to changes in fibrosis by studying patients with stable liver disease.
  
  
  METHODS
  We performed a retrospective analysis of 531 paired liver stiffness measurements made by Fibroscan when the study began (LSM1) and at follow-up (LSM2), more than 1 day and less than 1 year apart, from 432 stable (for body mass index, waist circumference, and alcohol consumption), untreated, immunocompetent patients with chronic liver disease (from January 2006 through March 2009). Variations between the first and follow-up measurements were expressed as absolute (LSM2-LSM1, kPa) or relative ([LSM2-LSM1]/LSM1*100) or as changes in fibrosis stage.
  
  
  RESULTS
  There was >20% variation in 49.7%, >30% in 34.3%, and >50% in 12.2% of paired measurements; this variation was constant across the spectrum of LSM1 values. The variations produced a 1-fibrosis stage difference in 31.5% of pairs and a ≥ 2-stage difference in 9.8% of pairs. Patients with LSM1 >7 kPa had increased probability of having a different stage of fibrosis at LSM2, compared with patients with LSM1 <7 kPa. Factors associated with variation included measurements made by 2 different operators or at least 1 non-senior operator, ratios of interquartile range:median values, significant fibrosis (≥ 7 kPa) at LSM1, baseline body mass index, or a 2-fold difference in level of alanine aminotransferase between measurements. When the analyses were restricted to measurements made by the same operator, the variation was slightly reduced; fibrosis stage differed between measurements for only 34.3% of cases.
  
  
  CONCLUSIONS
  Operator-related and patient-related factors produce significant variations in liver stiffness measurements made by transient elastometry, limiting its use in monitoring patients. These variations are unrelated to disease progression. The lowest levels of variation occur in measurements made in patients with no or early-stage fibrosis or by a single experienced operator.
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France; Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Nascimbeni
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Lebray
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Larysa
authors.initials: L
authors.lastname: Fedchuk
authors.affiliation: Department of Gastroenterology, Clinical Division (LIM-07), University of São Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Claudia P
authors.initials: CP
authors.lastname: Oliveira
authors.affiliation: School of Medicine, Universidade Federal do Rio Grande do Sul, Division of Gastroenterology and Hepatology, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Mario Reis
authors.initials: MR
authors.lastname: Alvares-da-Silva
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Varault
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Ingiliz
authors.affiliation: BioPredictive, Paris, France.
authors.forename: Yen
authors.initials: Y
authors.lastname: Ngo
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Mercedes
authors.initials: M
authors.lastname: de Torres
authors.affiliation: BioPredictive, Paris, France.
authors.forename: Mona
authors.initials: M
authors.lastname: Munteanu
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Poynard
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique Hôpitaux de Paris, Hôpital Pitié Salpêtrière, INSERM U938, CdR Saint-Antoine, Paris, France. Electronic address: vlad.ratziu@upmc.fr.
authors.forename: Vlad
authors.initials: V
authors.lastname: Ratziu
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008103:Liver Cirrhosis / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: ALT; BMI; Cirrhosis; Disease Progression; Liver Fibrosis Markers