Non-Invasive Assesment of Chronic Liver Disease by Two Dimensional Shear Wave Elastography: An Overview

Background: Liver Stiffness (LS) assessed by Sonoelastography (SE), has been demonstrated as reliable non-invasive indicator of liver fibrosis stage in patients with Chronic Liver Diseases (CLD). Sonoelastography performs best in ruling-out cirrhosis (F=4) and ruling-in signifficant fibrosis (F >= 2). However, it is insufficiently accurate to replace endoscopy for detection of Esophageal Varices (EV), being able to only ruling-out large EV. LS >= 25 kPa by Transient Elastography (TE) is considered highly suggestive for the presence of Clinically Significant Portal Hypertension (CSPH). Higher liver and spleen stiffness have been asociated with adverse clinical outcomes in CLD. Two-dimensional shear wave elastography (2D-SWE), the latest developed SE method, allows both visualisation and quantification of liver elasticity in real time superimposed over B-mode ultrasound image. Discussion: Meta-analysis of studies with Supersonic Shear Imaging (SSI) revealed comparable performance of this 2D-SWE to TE in fibrosis staging, with AUROCs 0.85 for F >= 2 (LS cut-off 8.04 kPa) and 0.93 for F=4 (LS cut-off 11.12 kPa). Few studies reported very good performance of 2D-SWE (SSI) to rule-in CSPH (AUROCs 0.79-0.95; LS cut-offs 15-25 kPa). While conflicting data exist with respect to its performance in predicting the presence of EV, prognostic utility of 2D-SWE (SSI) was demonstrated in a single study that reported 3.4-fold (P=0.026) higher risk of adverse outcome in patients with baseline LS >= 21.5 kPa followed over 28 months. Conclusion: 2D-SWE (SSI) might be used to stage liver fibrosis in CLD, identify patients with compensated cirrhosis under risk of adverse outcomes and potentially stratify risk of having CSPH and EV.