B-mode and contrast-enhanced ultrasonography for intestinal assessment in dogs: A review.

Ultrasound (USG) is a valuable diagnostic tool for evaluating the gastrointestinal tract of small animals, providing noninvasive and dynamic information. This review discusses intestinal evaluation in dogs using B-mode ultrasound and advanced contrast-enhanced ultrasound (CEUS) with microbubbles. B-mode USG allows the examination of the thickness and stratification of the intestinal wall, motility, and adjacent structures, such as lymph nodes and peritoneum to be examined. Reference values for intestinal wall thickness in dogs are based on body weight. The duodenum, jejunum, and ileum can be differentiated sonographically by location wall stratification, and relationship to other intestinal segments. Intestinal motility is assessed by counting peristaltic waves, and abnormalities indicate various diseases. CEUS uses microbubble-based contrast agents, such as sulfur hexafluoride, which remain stable in the vascular system and are eliminated by the lungs. This technique improves the perception of ultrasound echoes, making it possible to quantify tissue perfusion using parameters such as entry time, peak enhancement, and exit time. In human medicine, CEUS is used to assess intestinal perfusion in conditions such as Crohn's disease and ischemia. In veterinary medicine, this technique has been used to assess duodenal perfusion in healthy dogs and those with chronic enteropathies or alimentary lymphoma. Although CEUS shows potential in differentiating dogs with chronic enteropathies from healthy controls, more research is needed to standardize the methodology, establish reference values, and define clinical applications in various canine intestinal diseases. The combination of B-mode USG and CEUS provides a noninvasive assessment of intestinal morphology and function, contributing to the understanding of the pathophysiology of enteropathies in dogs.