Two-dimensional Shear Wave Elastography Utilized in Patients with Ascites: a More Reliable Method Than Transient Elastography for Noninvasively Detecting the Liver Stiffness—an Original Study with 170 Patients

Background:Two dimensional shear wave elastography (2D-SWE) is an ultrasound elastography technique based on shear waves implemented on a diagnostic ultrasound system. Transient elastography (TE) uses an ultrasound displacement M-mode and A-mode image produced by the system. So, TE mechanically induced impulse at tissue surface and difficultly across water. This paper compared the reliability and reproducibility of 2D-SWE with that of TE in patients with chronic hepatic disease. Comparisons were made in terms of the success rate, reliability, reproducibility, operation time, and influence of operator experience.Methods:A total of 170 patients were included in this study. Participants underwent 2D-SWE and TE performed by 2 different operators (a novice and veteran) on the same day. Nonparametric statistical tests were used to compare the technical success rate and reliable measurement rate, and inter-operator reproducibility was evaluated using intra-class correlation coefficients (ICCs).Results:The 2D-SWE technique showed a higher technical success rate than TE. Either 2D-SWE or TE can be utilized in patients with ascites lamella of less than 10 mm or ascites lamella plus skin-capsular distance of less than 25 mm. However, although the reliability rate of liver stiffness measurement with 2D-SWE did not significantly differ between the novice and veteran operators, for TE, there was a significant difference when body mass index (BMI) ≤25 kg/m2. When performed by the novice and veteran operators, 2D-SWE and TE both showed excellent inter-operator agreement, with ICCs of 0.968 and 0.973, respectively. Both 2D-SWE and TE displayed reliable measurement and excellent reproducibility in patients with chronic liver disease, were minimally influenced by operator experience.Conclusions:2D-SWE may be a more reliable method for clinical application in noninvasive detecting the liver stiffness.