Effectiveness of Ultrasound in Liver Stiffness and Fat Quantification

Overview

Liver stiffness is a marker for scarring of the liver, which occurs after damage from various liver conditions. Scarring prevents normal liver function and can lead to liver failure. Fatty liver is a common cause of liver damage and can contribute to scarring. Currently, liver biopsy serves as the 'gold standard' for assessing the degree of liver scarring and fatty infiltration, guiding treatment decisions. However, liver biopsy poses a significant risk of death and unpleasant side effects, including internal bleeding and pain. Moreover, due to the small sample of liver tissue obtained during the biopsy, the results can be misleading and may not provide an accurate overview of the liver's health. Therefore, there is an unmet need for a non-invasive method of measuring liver stiffness and fat content. Ultrasound-based methods utilize various properties of ultrasound waves to assess liver stiffness and fat levels. This study aims to recruit 100-120 patients with chronic liver disease. The investigators will assess liver stiffness and fat levels during patients' hospital visits for routine scans, biopsies, or clinic appointments. The resulting measurements of liver stiffness and fat obtained through ultrasound-based methods will be compared to patients' routine liver biopsies, routine FibroScan results (another non-invasive method routinely used in clinical care to assess patients' liver stiffness), and other non-invasive severity scores (calculated from results obtained from patients' routine blood tests, providing an overview of the extent of liver damage).

Elastography and fat quantification techniques are imaging methods integrated into the normal B-mode ultrasound. These techniques are extremely safe, with no additional risk compared to a normal ultrasound study. The advantage of using liver elastography/fat techniques to assess the degree of liver fibrosis/fatty change is that the techniques are non-invasive (no needles or biopsies) with higher patient acceptance and compliance. Shear wave elastography is a non-invasive technique that can quantify liver stiffness by measuring the speed of shear waves in the tissue of interest. Early studies have shown that the speed of the shear wave is closely associated with different stages of liver fibrosis. It has also been shown that the measurements can be reproduced by different investigators. Fatty changes, assessed by measurements called TAI, TSI, and EzHRI, are in the early stages of investigation and are proving to be robust. Early studies are mostly performed using elastography have been investigated using Fibroscan (vibration shear wave generator) techniques, and to a lesser extent using point and 2-D shearwave elastography. Fat quantification is also undertaken on the Fibroscan system, producing a Controlled Attenuation Parameter (CAP) measurement which can be correlated both to the fat quantification methods and biopsy result. The investigators have, through a previous project, demonstrated that liver stiffness, using point shear wave, on other machines can accurately identify different stages of liver fibrosis. The investigators would like to extend the study to include a further commercially available machine, namely Samsung RS85 Prestige, to study its diagnostic accuracy of point and 2-D elastography and the fat quantification techniques. As more machines with similar capabilities for stiffness and fat assessment become available, data would be collected from these also. In addition, this study will enrich scientific evidence in terms of how accurate elastography/fat assessment is as a method of measuring liver stiffness/fatty change and hopefully reduce the need to perform liver biopsy in the future.