Renal ultrasonographic strain elastography and symmetric dimethylarginine (SDMA) in canine and feline chronic kidney disease.

Chronic kidney disease (CKD) is a common renal disease in dogs and cats. Renal fibrosis is a main pathologic process leading of CKD progression. Renal biopsy is the gold standard for renal fibrosis assessment. However, it is not routinely performed in clinic due to its invasiveness. Therefore, the aim of this study was to evaluate the use of ultrasonographic strain elastography (SE), which is a non-invasive method for renal tissue stiffness determination and its association with renal function. Renal strain ratios and renal function were evaluated in 13 CKD dogs (CKDD), 38 healthy dogs (HD), 17 CKD cats (CKDC) and 26 healthy cats (HC). There were significantly lower renal cortical strain ratios than medullary strain ratios in all groups (HD; P<0.01, HC; P<0.01, CKDD and CKDC; P<0.05) and significantly lower cortical and medullary strain ratios in both CKDD and CKDC than in healthy control animals of both species (P<0.0001). In dogs, the renal cortical and medullary strain ratios significantly negatively correlated with plasma creatinine (P<0.05), blood urea nitrogen (BUN; P<0.05; P<0.01, respectively), and symmetric dimethylarginine (SDMA; P<0.01). In cats, similar correlations were found for plasma creatinine (P<0.001), BUN (P<0.05; P<0.001, respectively) and SDMA (P<0.05). SE might be a promising imaging diagnostic tool for renal-elasticity evaluation, also correlating with renal functional impairment in canine and feline CKD.