Computed tomographic findings of the gastrointestinal tract in rabbits

Gastrointestinal (GI) diseases are common in rabbits. Although diagnostic imaging studies can assist clinicians in selecting therapeutic approaches, there are few reports of advanced imaging findings in normal rabbits. Computed tomography (CT) is recognized as a useful tool in dogs and cats, but there are few reports of normal findings on multidetector computed tomography (MDTC) in rabbits. The goals of this study are to describe the CT anatomic imaging appearance of the GI tract and their normal variation in healthy pet rabbits and to obtain the normal wall thickness measurements of normal GI tract structures. Twenty-three rabbits were scanned under general anesthesia and the CT abdominal images were analyzed by two experienced radiologists. Location and size of the major GI organs and structures were determined, and wall thickness of the stomach, small and large intestines were measured, including the interobserver agreement. Statistical analysis of quantitative and qualitative variables was performed. Wall thickness values were established for the different parts of the stomach (cardia: 3.4 ± 0.4mm; fundus: 1.4 ± 0.2mm; body: 1.4 ± 0.1mm; pylorus: 2.9 ± 0.5mm), small intestines (duodenum: 1.4 ± 0.1mm; jejunum: 1.2 ± 0.1mm; ileum: 1.4 ± 0.1mm), and large intestines (cecum: 1.2 ± 0.1mm; colon ascending: 1.4 ± 0.3 mm and descending: 1.3 ± 0.3mm). When distended the stomach did not extend beyond the caudal limits of the L2 vertebra. The cecum occupied the ventral abdominal region from T12/T13 to L7/S1, the sacculus rotundus was identified in 11 of the 23 rabbits. The sacculus rotundus and vermiform cecal appendix were identified only in rabbits with mild large intestinal distension. It was possible to use CT to evaluate the different portions of the GI tract that are not normally readily visible on radiographs and ultrasound (US). Normal wall thickness values of the different portion of the GI tract were stablished. These results provide new and important reference values for CT studies in normal pet rabbits and provide data for further studies in rabbits with GI diseases.