Introduction to Liver Stiffness: A Novel Parameter for the Diagnosis of Liver Disease

Abstract

Since 2003, the noninvasive quantitation of liver stiffness (LS) by ultrasound-based transient elastography (TE) using Fibroscan^® has revolutionized the diagnosis of liver diseases, namely liver cirrhosis. Alternative techniques such as ARFI, 2D-SWE, or magnetic resonance elastography are likewise developed with a breathtaking speed. LS has evolved as an excellent surrogate marker of advanced fibrosis (F3) and cirrhosis (F4) outscoring all previous noninvasive approaches to detect cirrhosis. LS values below 6 kPa are considered as normal and exclude ongoing liver disease. LS of 8 and 12.5 kPa represent generally accepted cut-off values for F3 and F4 fibrosis. Starting from 12.5 kPa, clinical significant portal hypertension becomes likely and important endpoints such as liver-related death and all-cause mortality increase drastically. LS measurement is able to identify those who may develop cirrhosis in the future at least 10 years earlier. Many other factors may also increase LS such as hepatic infiltration with tumor cells, mast cells (mastocytosis), inflammatory cells (all forms of hepatitis), or amyloidosis. In addition, LS is directly correlated with the venous pressure (e.g., during liver congestion) and increased during mechanic cholestasis. Thus, LS should always be interpreted in the context of clinical, imaging, and laboratory findings. Finally, LS has helped to better understand the molecular mechanisms underlying liver fibrosis, namely the role of sinusoidal pressure elevation and hepatic arterialization.