LAUSR

Background The ultrasonographic examination technique is a well-established, non-invasive diagnostic tool for diverse conditions in humans and different animal species. The purpose of our study was to describe ultrasonographic localisation, sonographic appearance and dimensions of the kidneys and spleen of clinically healthy llamas and alpacas. Differences between llamas and alpacas and the influence of sex and ages were investigated. Results of this study may aid veterinarians performing ultrasonography in diseased animals and the technique can be used for routine protocol screening. Results Ultrasonography was performed in 135 clinically healthy, non-sedated llamas and alpacas. Screening was performed with a 6.6 MHz curve linear transducer with only alcohol as contact medium between the probe and unclipped skin. The kidneys could be imaged from the paralumbar region. The right kidney only was visualized when scanning from the right and the left kidney only from the left. While the left kidney appeared in sagittal view as an oval shape in most llamas and alpacas, in one third of animals the left kidney had a triangular shape. The L-shaped base of the spleen, with its homogeneous, echoic pattern, could be seen craniolateral to the left kidney. Anechoic areas displaying vessels inside the spleen and a thin echoic capsule surrounding the splenic tissue could be differentiated. While sonographic appearances of the examined organs showed no differences between llamas and alpacas, selected dimensions of both of kidney and spleen showed significant differences between species. In terms of age and sex, significant differences in respect of kidney size could be found only in alpacas. Sex seemed to have no influence on kidney and spleen sizes in llamas. Conclusions The present study provides species-specific information on ultrasonographic appearance and reference values for kidney and spleen dimensions of clinically healthy llamas and alpacas. Results show differences in organ sizes between llamas and alpacas and in alpacas of different sex and age. The results of this study can be used as references for veterinarians performing ultrasound examinations in diseased animals.