Liver steatosis (CAP) as modifier of liver stiffness

Abstract

Liver stiffness (LS) is a tissue characteristic that reflects a combination of fibrosis stage, liver perfusion and inflammation, and is modulated by several technical confounders of the measurement technique. Liver steatosis results from metabolic alterations associated with diabetes mellitus and obesity. It is defined by the presence of lipid droplets within the hepatocytes which alter ultrasound propagation and physical tissue properties. This chapter focuses on the potential modulation of LS by steatosis and discusses noninvasive ultrasound-based methods of steatosis quantification as potential modifiers of LS interpretation. In summary, steatosis-induced modulation of liver stiffness remains a topic of ongoing debate. Although no specific recommendation can be given, most studies indicate a reduced diagnostic precision of LSM in patients with severe steatosis and obesity, which especially impairs the positive predictive value of LSM for ruling in advanced fibrosis. In some cohorts, steatosis is not at all or even slightly negatively correlated with LS. There are individual case observations, in the absence of inflammation, where a decrease of steatosis/CAP during alcohol detoxification leads to a slight elevation of LS. Future studies should prospectively analyze the effect of steatosis on LS in further detail.