JSUM ultrasound elastography practice guidelines: liver

Abstract

In diffuse liver disease, it is extremely important to make an accurate diagnosis of liver fibrosis prior to determining indications for therapy or predicting treatment outcome and malignant potential. Although liver biopsy has long been the gold standard in the diagnosis of liver fibrosis, it is still an invasive method. In addition, the sampling error is an intrinsic problem of liver biopsy. Non-invasive serological methods for the diagnosis of liver fibrosis can be affected by factors unrelated to the liver. Recently, after the introduction of FibroScan, it became possible to measure liver fibrosis directly and non-invasively by elastography, which has attracted attention as a non-invasive imaging diagnostic tool for liver fibrosis. In addition, real-time tissue elastography is currently being used to conduct clinical trials at many institutions. Moreover, virtual touch quantification enables the observation of liver stiffness at any location by simply observing B-mode images. Furthermore, the recently developed ShearWave elastography visualizes liver stiffness on a color map. Elastography is thought to be useful for all types of diffuse liver diseases. Because of its association with portal hypertension and liver carcinogenesis, elastography is expected to function as a novel prognostic tool for liver disease. Although various elastographic devices have been developed by multiple companies, each device has its own measurement principle, method, and outcome, creating confusion in clinical settings. Therefore, it is extremely important to understand the characteristics of each device in advance. The objective of this guideline, which describes the characteristics of each device based on the latest knowledge, is for all users to be able to make the correct diagnosis of hepatic fibrosis by ultrasound elastography.

Accuracy of Real-Time Tissue Elastography for the Evaluation of Hepatic Fibrosis in Patients with Chronic Hepatitis B: A Prospective Multicenter Study

“…RTE measures the relative stiffness of the tissue in the region of interest (ROI) caused by the heartbeat using a combined autocorrelation method [14,15,16,17]. RTE displays the stiffness by overlying the B-mode image in the ROI with a color; the colors range from blue to red and indicate the relative softness and hardness of the area, respectively.…”

Romanian national guidelines and practical recommendations on liver elastography

“…The following requirements are necessary in order to obtain high quality elastography images [119]: high quality US images, without rib shadows, should be obtained; RT-E images must be displayed periodically, based on compressions induced by cardiac/vascular motion and not by applying an external pressure with the ultrasound probe; the RT-E image is obtained during breath holding at the end-expiration phase; the region of interest (ROI) must not contain large blood vessels; ROI should be placed at a certain distance from the surface of the liver (displayed in blue, due to multiple reflection echoes).…”

Prediction of Hepatocellular Carcinoma Incidence Risk by Ultrasound Elastography

“…While strain elastography enables the measurement (display) of liver fibrosis, measurement values in shear wave elastography are affected by inflammation, jaundice, and congestion in addition to fibrosis []6-9]. In other words, measurement values with the latter technique increase as fibrosis, inflammation, jaundice, and congestion exacerbate, and vice versa, presumably because these pathological conditions alter the density, and thereby the elasticity and viscosity, of liver tissue [10]. …”