Assessment of Renal Measurements and Position in the Syrian Hamster (Mesocricetus auratus) Using Survey Radiography...

Although renal disease in Syrian hamsters (SHs) has been reported, imaging studies of normal kidneys in this commonly used pet and laboratory species are lacking, despite the key role of imaging in diagnosis. This study aimed to examine kidneys of Syrian hamsters using radiographic and anatomical methods, focusing on kidney location, visibility, size, and its ratio to the second lumbar vertebra, along with the effects of sex, body size, side, and recumbency. Abdominal radiographs were obtained from 29 clinically healthy adult Syrian hamsters of both sexes to assess kidney visibility, position, and size as well as the length of second lumbar vertebral body on lateral and ventrodorsal (VD) views, followed by an in situ anatomical study for comparative analysis. The kidneys were typically located opposite the first to third lumbar vertebrae. On VD views, the left kidney was generally visible, whereas the right was identified in only 28%. The mean values of radiographic RKL, LKL, and 2LVL were 15.2 mm, 12.44 mm, and 14.27 mm, respectively, and the KL/2LVL ratio ranged from 2.66 to 4.00. No significant sex differences were observed in KL or the KL/2LVL ratio in either anatomical or radiographic measurements (p > 0.05). Sex had a significant effect on both radiographic and anatomical 2LVL measurements, with females generally showing higher values than males. Unlike the anatomical measurements, no significant differences between sides were found in radiographic KL and the KL/2LVL ratio. The radiographic RKL, LKL, and 2LVL were significantly larger than those obtained from anatomical measurements. No significant correlation was found between KL, 2LVL, or the KL/2LVL ratio and body length or body weight in either radiographic or anatomical measurements, except for a correlation between body weight and anatomical KL. Right and left kidneys were symmetrically placed, as in rats, but differed from rabbits and guinea pigs. Kidney visibility on VD views was similar to that reported in rabbits. Radiographic RKL, LKL, and 2LVL values differed from those of rodents and rabbits. The radiographic ratio was larger than the values reported in rats, chinchillas, guinea pigs, and rabbits. A single KL-to-2LVL ratio reference range applies to both kidneys and sexes, simplifying clinical assessment.