Relationship between integrated backscatter and pathological changes of renal cortex during acute renal failure in rabbits

Objective To investigate the changes of integrated backscatter (IBS) of renal cortex and explore their relation to pathological changes of renal cortex during acute renal failure (ARF) in rabbits.Methods The model of ARF was established in rabbits through the intramuscular injection of 50% glycerin (12～15 ml/kg) into the hind leg. Ultrasonic examination was performed on the day before (T 0) and days 1, 3…13 after the injection (T 1,T 3…T 13 ) to measure the IBS of the renal cortex, medulla and sinus. The ratios of IBS of the renal cortex and that of medulla to that of sinus were regarded as the revised IBS (IBS%) of the renal cortex and medulla. Then a correlative analysis was conducted between the IBS% and pathological changes in the renal cortex and medulla.Results The significant increase of IBS% of the renal cortex appeared at T 3, peaked at T 7 and remained abnormal still at T 13 ( P 0.05 ). However, no significant change in IBS% of renal medulla was found. Pathological changes were mainly found in the renal cortex :① casts forming in the renal tubule;② swelling, necrosis and defluxion of the renal tubular epithelial cells;③ renal interstitial edema. These changes occured at T 1, peaked at T 7 and T 9 and remained abnormal at T 13 .Conclusions During ARF, IBS% of the renal cortex is significantly increased,which is closely related to the degree of renal cortical pathological changes. There is no significant change in the IBS% of the renal medulla. The increase in IBS% of the renal cortex during ARF is related to various pathological factors.