Is There Consensus among Sonographers and Radiologists in Grading Fatty Liver Disease and Detecting Liver Pathological Features in B-Mode Images?

Abstract

Hepatic steatosis is the leading cause of chronic liver disease. Reliable detection and staging of liver disease using ultrasound is important to facilitate diagnosis and treatment. The aim of this study was to evaluate the interobserver agreement between trainee sonographers, qualified sonographers and radiologists in grading non-alcoholic fatty liver disease (NAFLD) and detecting common liver pathological features on B-mode images. 150 B-mode liver ultrasound images from 50 adult patients referred for abdominal ultrasound were obtained retrospectively from a PACS system. The images were independently graded for the severity of hepatic steatosis (normal, mild, moderate or severe) and the detection of incidental findings, focal fatty sparing, liver surface irregularity and rounded liver edge (present or absent) by 17 qualified, six trainee sonographers and six radiologists. Fleiss’ kappa statistic was used to calculate interobserver agreement. The interobserver agreement rates among trainee sonographers for the detection of incidental findings, focal fatty sparing, liver surface irregularity and rounded liver edge were: κ = 0.243, 0.486, 0.155 and 0.079 respectively. Among qualified sonographers, the agreement rates were: κ = 0.323, 0.428, 0.167 and 0.152 respectively. Among radiologists, the agreement rates were: κ = 0.156, 0.266, 0.015 and 0.154 respectively. Visual assessment of NAFLD and common liver pathology in B-mode imaging has low interobserver agreement among sonographers and radiologists. The low agreement levels are likely caused by a lack of standardised assessment criteria. The development of standardised criteria for staging common liver pathological features are recommended.