Quality criteria for liver stiffness measurement by transient elastography

Abstract

Liver elastography offers the possibility of a quick, noninvasive, and painless evaluation of the liver with immediate results at bedside. Liver stiffness measurements (LSM) using transient elastography (TE) appear very easy to perform, however, several conditions must be respected to ensure an optimal evaluation. Thus, patient, operator, and examination characteristics have all been shown to influence the result of LSM. Food intake increases liver stiffness (LS), whereas recent withdrawal in alcoholics is associated with a decrease of LS. Around one hundred exams seem to be required before considering an operator as sufficiently trained for using e.g. a FibroScan device. The measurement site and the FibroScan probe must be correctly chosen to ensure the best quality of LSM. Finally, the intrinsic characteristics of the measurement, especially the IQR/M ratio, must be carefully checked to avoid overestimation of LS. Most of the results come from studies which have evaluated TE, with less data available for the other technologies such as 2D- and point shear wave elastography which require dedicated ultrasound knowledge. For TE, all operators should know and apply the quality criteria for LSM to ensure the reliability of the results and therefore the best management of patients in clinical practice.