title: Controlled attenuation parameter for evaluating liver steatosis in chronic viral hepatitis.
abstract: OBJECTIVE
  To assess the performance of controlled attenuation parameter (CAP) in patients with chronic viral hepatitis.
  
  
  METHODS
  CAP is a new technique that measures the attenuation in the liver of an ultrasound beam, which is directly related to lipid accumulation. Consecutive patients undergoing liver biopsy for chronic viral hepatitis were studied using the M probe of FibroScan device (Echosens, Paris, France). The device estimates liver steatosis in decibel per meter (dB/m). An expert operator performed all measurements. Steatosis was graded according to Kleiner's classification. Pearson or Spearman rank coefficient was used to test correlation between two study variables. Linear regression was used for multivariate model to assess the association between CAP and other variables. Receiver operating characteristic curve analysis was performed to calculate area under the curve (AUROC) for S0 vs S1-S3 and S0-S1 vs S2-S3.
  
  
  RESULTS
  115 subjects (85 males and 30 females) were prospectively studied. The mean values of CAP were 227.1 ± 43.1 for S0; 254.6 ± 38.9 for S1; 297.8 ± 49.4 dB/m for S2-S3. In univariate analysis CAP showed a significant correlation with age, body mass index (BMI), degree of steatosis, and cholesterol. Multivariate regression analysis confirmed the correlation with the degree of steatosis [coefficient, 1.2 (0.60-1.83); P < 10(-5)] and BMI [coefficient, 4.1 (0.5-7.8); P = 0.03] but not with all other variables. Optimal cutoff values for S ≥ 1 and S ≥ 2 were 219 dB/m [AUROC, 0.76 (0.67-0.84); sensitivity, 91.1% (78.8-97.5); specificity, 51.6% (38.7-64.2); positive predictive value, 56.9% (44.7-68.6); negative predictive value, 89.2% (74.3-97.0); positive likelihood ratio, 1.88 (1.4-2.5); negative likelihood ratio, 0.17 (0.07-0.5)] and 296 dB/m [AUROC, 0.82 (0.74-0.89); sensitivity, 60.0% (32.3-83.7); specificity, 91.5% (83.9-96.3); positive predictive value, 52.9% (27.8-77.0); negative predictive value, 93.5% (86.3-97.6); positive likelihood ratio, 7.05 (3.2-15.4); negative likelihood ratio, 0.44 (0.2-0.8)], respectively.
  
  
  CONCLUSIONS
  Controlled attenuation parameter could be a useful tool in the clinical management of patients with chronic viral hepatitis for detecting liver steatosis.
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Ferraioli
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Tinelli
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Lissandrin
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Mabel
authors.initials: M
authors.lastname: Zicchetti
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Dal Bello
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Filice
authors.affiliation: Giovanna Ferraioli, Raffaella Lissandrin, Mabel Zicchetti, Gaetano Filice, Carlo Filice, Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, Medical School University of Pavia, 27100 Pavia, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Filice
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001706:Biopsy; D003430:Cross-Sectional Studies; D005234:Fatty Liver / Q000150:complications / Q000503:physiopathology*; D005260:Female; D019698:Hepatitis C, Chronic / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: Chronic liver disease; Controlled attenuation parameter; Liver steatosis; Noninvasive techniques; Transient elastography