Evaluation of the Feasibility of 2D-SWE to Measure Liver Stiffness in Healthy Dogs and Analysis of Possible Confounding Factors

SIMPLE SUMMARY: Currently, there is a lack of diagnostic methods for liver fibrosis in veterinary medicine. Two-dimensional shear wave elastography is a non-invasive diagnostic technique widely used in human medicine. However, there is a limited amount of relevant research in veterinary medicine, with only a few studies available. These studies suffered from small sample sizes, and the results of different experiments contradict each other. The aim of this study was to measure the range of liver stiffness in healthy dogs and to investigate the factors influencing it. We found that liver stiffness in healthy dogs was 3.96 ± 0.53 kPa, which was influenced by anesthesia and measurement site. These findings provided a theoretical basis and data support for its application in veterinary clinical practice. At the same time, the determination of health values contributed to the subsequent study of two-dimensional shear wave elastography in dogs. ABSTRACT: (1) Background: Two-dimensional shear wave elastography (2D-SWE) is a non-invasive method widely used in human medicine to assess the extent of liver fibrosis but only rarely applied to veterinary medicine. This study aimed to measure liver stiffness in healthy dogs and investigate the factors that impacted 2D-SWE measurement. (2) Methods: In total, 55 healthy dogs were enrolled and subjected to 2D-SWE measurements before and after anesthesia administration. Post-anesthesia 2D-SWE measurements and computerized tomography (CT) scans were obtained. (3) Results: The liver stiffness range in healthy dogs was 3.96 ± 0.53 kPa. In a stratified analysis based on confounding factors, liver stiffness was influenced by measurement site and anesthesia, but not by sex. No correlation was observed between liver stiffness and weight or liver CT attenuation. (4) Conclusions: 2D-SWE is feasible for liver stiffness measurement in dogs. Anesthesia and measurement site are sources of variability. Therefore, these factors should be considered while recording 2D-SWE measurements. Our data on liver stiffness in healthy dogs can serve as the basis for future studies on 2D-SWE to assess pathological conditions in dogs.