Diagnostic imaging of the normal common marmoset (Callithrix jacchus)

Abstract

Standard thoracic and abdominal radiographic and abdominal ultrasonographic procedures were developed in the common marmoset. A description and reference values for the corresponding radiographic anatomy, including the relevant skeletal system, and normal abdominal echoanatomy is provided. Radiographs and ultrasonographic examinations were evaluated from 17 anaesthetized healthy mature marmosets ranging from 1.5 to 9 years and 328 g to 506 g. Left-to-right lateral recumbent and ventrodorsal whole body radiographs made at end inspiration are recommended. Radiographic images of the heart, lungs, liver, gastric axis, and at least one kidney could be evaluated consistently. A generalized interstitial/peribronchial pattern was normally present. The mean of the vertebral heart size +/- SD on dorsoventral or ventrodorsal views was 9.42 (+/- 0.44), ranging from 8.8 to 10.6. Abdominal contrast was mostly poor. The gastrointestinal structures could often only be identified due to their luminal gas. The right liver lobes were prominent and extended caudally far beyond the costal arch. The pylorus was located centrally and the spleen could not be seen, which is similar to the cat. Additionally, pancreas, lymph nodes, urinary bladder and ureters were not seen. There was a statistically significant difference (p < 0.05) between female and male kidney length. Good ultrasonographic images of the kidneys, bladder, spleen, adrenal glands, liver and the gastrointestinal tract could be obtained. The pancreas, caecum and abdominal lymph nodes were not seen. The spleen was the least echogenic organ, followed by the medium echogenic liver and the sometimes isoechoic, but mostly hyperechoic renal cortex. The kidneys had poor corticomedullary distinction. The gallbladder had a bi- to multilobed appearance with a wide, tortuous cystic duct. The adrenal glands were readily seen, but should not be confused with the adjacent spleen. The prominent right liver lobes, the central pyloric position, and the statistically significant difference (p < 0.05) between female and male kidney length was consistent with the radiographic findings. A statistically significant (p < 0.05) difference between female and male right adrenal gland length was present. This study emphasizes that significant species specific differences exist between dogs and cats and the common marmoset. Simply applying canine or feline radiographic or ultrasonographic interpretation principles may result in misdiagnosis.