Radiologic Measurement and Determination of Kidney-to-Vertebra Ratios as a Method of Estimating Renal Size in Servals (Leptailurus serval)
Numerous conditions, from acute to chronic renal changes, have the potential to alter the renal size on radiographs. However, current literature does not provide any radiographic reference range for the normal renal size in the serval (Leptailurus serval). This retrospective study includes 13 healthy adult servals, seen between 2004 and 2017 at the UTCVM Veterinary Medical Center, deemed healthy based on physical examination, blood work. Orthogonal radiographs were anonymized, calibrated and evaluated blindly by three observers of different experience level. Renal and individual lumbar vertebral body length were measured on both orthogonal views, and ratios of kidney length to each lumbar vertebral length were calculated on both views. On the ventrodorsal projection, the kidney length to L5 vertebra ratio had the lowest standard deviation, with a mean of 1.82, standard deviation of 0.27, and 95% confidence interval (1.63–2.00). On the lateral view, the kidney length to L3 vertebra ratio had the lowest standard deviation, with a mean of 2.03, standard deviation of 0.25, and 95% confidence interval (1.86–2.20). Using a Tukey-Kramer test, all 3 observers were shown to be in agreement, indicating reproducibility of the measurements among observers with different level of expertise.
The authors would like to thank Xiaocun Sun for her assistance with the statistical analysis.