Reference number: OPUSeJ 201301272208CAP
Title: Controlled Attenuation Parameter (CAP): a noninvasive method for the detection of hepatic steatosis based on transient elastography
Authors: Robert P. Myers 1, Aaron Pollett 2, Richard Kirsch 2, Gilles Pomier-Layrargues 3, Melanie Beaton 4, Mark Levstik 4, Andres Duarte-Rojo 5, David Wong 5, Pam Crotty 1 and Magdy Elkashab 6
Abstract: Background: Accurate tools for the noninvasive detection of hepatic steatosis are needed. The Controlled Attenuation Parameter (CAP) specifically targets liver steatosis using a process based on transient elastography.
Methods: Patients with chronic liver disease and body mass index (BMI) ≥28 kg/m2 underwent biopsy and liver stiffness measurement (LSM) with simultaneous CAP determination using the FibroScan® M probe. The performance of the CAP for diagnosing steatosis compared with biopsy was assessed using areas under receiver operating characteristic curves (AUROC).
Results: A total of 153 patients were included: 69% were male, median BMI was 32 kg/m2; 47% had nonalcoholic fatty liver disease (NAFLD); and 65% had significant (≥10%) steatosis. The CAP was significantly correlated with the percentage of steatosis (ρ = 0.47) and steatosis grade (ρ = 0.51; both P < 0.00005). The median CAP was higher among patients with significant steatosis (317 [IQR 284–339] vs. 250 [227–279] dB/m with <10% steatosis; P < 0.0005) and the AUROC for this outcome was 0.81 (95% CI 0.74–0.88). At a cut-off of 283 dB/m, the CAP was 76% sensitive, 79% specific, and had positive and negative predictive values of 87% and 64%, respectively. CAP performance was not influenced by measurement variability, but was higher in patients with mild (F0-F1) fibrosis (AUROC 0.89 vs. 0.72 with F2-F4; P = 0.03). The AUROCs of the CAP for ≥5%, >33% and >66% steatosis were 0.79, 0.76 and 0.70, respectively.
Conclusions: The CAP is a promising tool for the noninvasive detection of hepatic steatosis. Advantages of CAP include its ease of measurement, operator-independence and simultaneous availability with LSM for fibrosis assessment.Author bio: N/A
Sponsor editor: N/A
1 Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
2 Department of Pathology, Mt. Sinai Hospital, Toronto, Ontario, Canada
3 Liver Unit, Centre Hospitalier de l’Université de Montréal, Hôpital Saint-Luc, Montréal, Quebec, Canada
4 Multi-Organ Transplant Unit, University of Western Ontario, London, Ontario, Canada
5 Toronto Western Hospital Liver Centre, Toronto, Ontario, Canada
6 The Toronto Liver Centre, Toronto, Ontario, Canada
Keywords: biopsy; elastography; fatty liver; steatosis
Subject: Medicine/ steatosis
Bibliography: (alphabetical) N/A
Citation: Myers, R P et al, 2012, “Controlled Attenuation Parameter (CAP): a noninvasive method for the detection of hepatic steatosis based on transient elastography”, Liver International, 32: 902–910. doi: 10.1111/j.1478-3231.2012.02781.x http://onlinelibrary.wiley.com/doi/10.1111/j.1478-3231.2012.02781.x/abstract