Study On Renal Perfusion Of Chronic Renal Failure In Rabbits With Contrast-enhanced Ultrasound

Objective: To access the renal perfusion of chronic renal failure (CRF) at different stages in rabbits by contrast-enhanced ultrasound with time-intensity curve, compared with the pathological changes and serum creatinine (Scr), blood urea nitrogen (BUN).Methods: Fifteen rabbit CRF models were established by intravenously injecting cationic bovine serum albumin (C-BSA) for 8 weeks. Scr and BUN were examined at pre-injection and 2w, 4w, 6w, 8w post-injection. Renal size was measured by 2D ultrasound at the same time points, and then contrast-enhanced ultrasound was performed on bilateral kidney. Renal perfusion was analyzed quantitatively with the time-intensity curve by Wash-in/Wash-out software. The parameters of the time intensity curve include time to enhancement (ET), time to peak intensity (PIT), peak signal intensity (PSI), area under the curve (AUC) and time to half of peak intensity (HPT). After that one rabbit was sacrificed randomly at each time point and its kidney was sampled for pathological examination. Investigate the changes of blood perfusion and time-intensity curve parameters in CRF rabbits at different stages with reference to the pathology and blood biochemistry.Results: The level of Scr and BUN has increased since 6w after injection of C-BSA. 2D ultrasound showed the renal volume was enlarged and the cortex was thickened from 2w to 6w post-injection; the pathological examination exhibited glomerular cyst cavity expanding, glomerular cell swelling, and inflammatory cell infiltration and exudate. At 8w post-injection, the renal size had a decreasing trend and pathological studies showed glomerular sclerosis, renal interstitial fibrosis and tubular atrophy. Renal cortical perfusion reduced from 4w, manifested as the PSI of the time-intensity curve parameters decreased. The speed of infusion and clearance was slower, shown as PIT and HPT delayed. Compared with pre-injection, there was no difference in AUC at 2w, 4w and 6w post-injection, and then AUC decreased at 8w post-injection.Conclusions: Contrast-enhanced ultrasound combined with time-intensity curve can analyze renal perfusion of CRF quantitatively at different stages. The reduction of renal perfusion was earlier than the changes of routine laboratory indexes in CRF. The change of haemodynamic was closely related with pathology.