Abdominal Wall Thickness Affects Liver Stiffness Measurements by 2-D Shear Wave Elastography in Patients with Chronic Liver Disease

Abstract

This study was conducted to define the effect of abdominal wall thickness (AWT) and its composition on the level of confidence in liver stiffness (LS) measurements obtained with 2-D shear wave elastography (2-D-SWE) in patients with chronic liver disease. In this retrospective study, a total of 1291 patients who underwent LS measurement by 2-D-SWE were enrolled. The abdominal wall was divided into three layers: layer 1 extended from the skin to the subcutaneous fat layer; layer 2 was the muscle layer; and layer 3 extended from the peritoneum to the liver capsule (including the omental fat layer, if present). We regarded the sums of layers 1-3 and layers 1 and 3 as the AWT and non-muscular layer thickness (NMT). Age/sex/body mass index-adjusted multivariate logistic regression analysis was performed to identify factors influencing the level of confidence of LS measurements. Three hundred eighty-six patients (29.9%) were classified in the unreliable LS group (standard deviation/median LS > 0.1). The fourth quartile of AWT and third and fourth quartiles of NMT/AWT were significantly associated with unreliable LS values (odds ratios = 2.103, 1.753 and 1.695, respectively). In conclusion, high AWT and NMT/AWT ratios reduce the confidence in LS measurements obtained with 2-D-SWE.

Keywords: Abdominal wall; Elasticity imaging techniques; Fibrosis; Liver.