CHAPTER 7 - Staging liver fibrosis with shear wave elastography

Abstract

Currently, guidelines have recommended that shear wave elastography (SWE) techniques can replace liver biopsy for fibrosis staging in several clinical scenarios. Indeed, liver biopsy for chronic liver disease is now seldom required outside the research setting. Stiffness is a quantitative estimate, whereas the histological scoring systems for liver fibrosis are based on categorical scales. Therefore, even in the “ideal” conditions, an overlap between consecutive stages of liver fibrosis is inevitable when using liver stiffness as a surrogate marker of liver fibrosis. From a clinical point of view, the term compensated advanced chronic liver disease (cACLD), which includes F3 and F4 stages, is currently used. Based on it, in patients with chronic viral hepatitis and nonalcoholic fatty liver disease the “rule of 4” has been proposed for the acoustic radiation force imaging techniques and the “rule of 5” for vibration controlled transient elastography (VCTE). SWE techniques can be used also to evaluate the clinical outcome, including the risk of liver-related events after successful antiviral treatment. In patients with alcohol-related liver disease, cACLD is the main predictor of long-term survival; therefore it is of utmost importance to diagnose patients with advanced fibrosis before decompensation occurs to promote abstinence and to improve survival. Very few studies for assessing liver fibrosis in cholestatic and autoimmune liver disease exist and have been performed in a small number of subjects, mostly using VCTE. In children, SWE techniques can be used to separate normal from abnormal as well as serially monitor individuals over time for disease progression or regression in the treatment setting.