Comparison of renal ultrasonographic measurements between healthy cats of three cat breeds: Ragdoll, British Shorthair and Sphynx

Abstract

Healthy cats of three cat breeds -- Sphynx (n = 11), British Shorthair (n = 15) and Ragdoll (n = 15) -- were included in this study. All cats underwent an ultrasonographic examination to assess renal length, cortical thickness, medullary thickness and corticomedullary ratio. Of all ultrasonographic measurements, renal length showed the highest variation. For all ultrasonographic dimensions, individual and kidney side (left vs right) variation were much more pronounced than interbreed variation. Sphynx cats tended to have larger kidneys (4.09 ± 0.33 cm) than British Shorthair (3.77 ± 0.43 cm) and Ragdoll cats (3.87 ± 0.41 cm). British Shorthair cats, however, tended to have a thinner cortex (0.67 ± 0.13 cm) and medulla (0.76 ± 0.18 cm) than Sphynx (0.76 ± 0.14 cm and 0.90 ± 0.25 cm, respectively) and Ragdoll cats (0.75 ± 0.13 cm and 0.91 ± 0.22 cm, respectively). However, statistical tests did not reveal significant differences between these cat breeds. The corticomedullary ratio was similar for the three cat breeds (Sphynx: 0.93 ± 0.43; British Shorthair: 0.91 ± 0.26; Ragdoll: 0.88 ± 0.31). The left kidney (3.83 ± 0.42 cm) was significantly smaller than the right kidney (3.99 ± 0.40 cm) and showed a thicker medulla (left: 0.93 ± 0.21 cm, right: 0.79 ± 0.22 cm), and thus a lower corticomedullary ratio (left: 0.80 ± 0.23, right: 1.01 ± 0.32). For the cortical thickness, no significant difference was observed between the left (0.71 ± 0.14 cm) and right kidney (0.74 ± 0.14 cm).

Impact of gonadal status on ultrasonographic renal parenchymal dimensions in healthy cats

“…Ultrasonography provides high-quality images and information about the physical structure of the kidneys, so ultrasonography can be considered a reference modality for feline renal imaging. 5 In human medicine, decreasing cortical thickness measured by ultrasonography is used for early detection of renal failure and reduced estimated glomerular filtration rate (eGFR). 6,7 This suggests cortical thickness may be an indicator of CKD in cats, and may be useful in assessing disease progression.…”

“…Renal dimensions of cats, including renal length, cortical thickness and medullary thickness, are affected by several factors, including kidney location, body weight, age and sex. 5,8,9 Gonadal status is another factor that must be considered. It has been noted radiographically that neutered cats have a lower ratio of renal length to the length of the second lumbar vertebra (L2) than intact cats.…”

Feline abdominal ultrasonography: what’s normal? what’s abnormal? The kidneys and perinephric space

“…4,[7][8][9][10][11] A study in 2013 reported mean renal size in three cat breeds: Sphynx (4.09 ± 0.33 cm), British Shorthair (3.77 ± 0.43 cm) and Ragdoll (3.87 ± 0.41 cm). 12 The ratio of cortical to medullary thickness was reported to be similar in all three cat breeds: Sphynx 0.93 ± 0.43, British Shorthair 0.91 ± 0.26 and Ragdoll 0.88 ± 0.31. 12 In some large breeds such as the Maine Coon, kidney size may naturally be slightly larger and fall outside of the normal range.…”

“…12 The ratio of cortical to medullary thickness was reported to be similar in all three cat breeds: Sphynx 0.93 ± 0.43, British Shorthair 0.91 ± 0.26 and Ragdoll 0.88 ± 0.31. 12 In some large breeds such as the Maine Coon, kidney size may naturally be slightly larger and fall outside of the normal range. In some cats, the right kidney may be slightly longer than the left, but the two kidneys should still be similar in length.…”

“…In some cats, the right kidney may be slightly longer than the left, but the two kidneys should still be similar in length. 4,9,11,12 Which kidney is which?…”