Validation of the Second Generation of the Controlled Attenuation Parameter (CAP) Using the MRI-PDFF as Reference

Overview

Chronic liver diseases (CLDs) represent a major worldwide public health burden. Worldwide estimations show that 844 million people have CLDs, a lot more than other chronic diseases such as diabetes or cardiovascular diseases. CLD is most of the time an asymptomatic, progressive, and potentially fatal disease. With its complications it becomes one of the major causes of mortality worldwide. Globally, hepatitis B virus and hepatitis C virus, alcoholic liver disease and non-alcoholic steatohepatitis, are the most important causes of liver disease. The diagnosis of liver lesions remains an important issue for these patients. The prognosis and management of liver disease greatly depends on the amount of liver fibrosis. In early stages, it is the main factor predicting long-term outcome of these patients. The liver biopsy still represents the gold standard diagnostic tool for liver fibrosis assessment, although a wide spectrum of noninvasive tools are now commonly used as a surrogate to the liver biopsy. It includes direct and indirect serum markers of liver fibrosis, but also several imaging-based methods, including transient elastography (FibroScan®, Echosens, Paris, France). Even if the liver fibrosis is the key pathological feature of progressive liver disease, the accumulation of excessive hepatic triglyceride, hepatic steatosis, is today recognized as an important factor in the pathogenesis of a number of CLD. The magnetic resonance imaging (MRI) techniques are sensitive to steatosis and show interesting diagnostic performances, especially the MRI using the proton density fat fraction (MRI-PDFF) which has shown at least equivalence in accuracy for quantifying hepatic steatosis with both 1H Magnetic Resonance Spectroscopy and with histological grade, across several studies. Therefore, this technique is now part of the gold standard diagnostic tool to establish the grade of hepatic steatosis. Echosens has developed an ultrasonic controlled attenuation parameter (CAP) designed to quantify hepatic steatosis using a process based on vibration controlled transient elastography (VCTE™). Echosens is working on improving the diagnostic accuracy of the CAP measurement performed with the FibroScan. This protocol is set-up to compare the diagnostic performances of the first generation of the CAP and the second generation of the CAP to the reference, the MRI-PDFF, in patients with CLD, all etiologies combined.