Comparison of diagnostic value of duplex and color Doppler ultrasound in experimental acute renal failure in rabbits

Objective To compare the diagnostic value of two dimentional ultrasound, spectrum and color Doppler ultrasound in experimental acute renal failure(ARF) in rabbits.Methods 50% glycerin (12～15 ml/kg ) were injected into the thigh muscle of the back leg of the rabbit to induce an animal model of ARF. Ultrasonic examination was performed on the day before (T 0) and days 1,3…13 after the injection(T 1,T 3…T 13 ). Renal size was evaluated by two dimensional ultrasound. The hemodynamic changes of the kidney were quantitatively analysed by spectrum Doppler,while color Doppler flow imaging(CDFI) and color Doppler power imaging(CDPI) were used to qualitatively study the blood perfusion of the kidney during ARF. The renal imaging in CDFI and CDPI were classified three grades.Grade Ⅰ,the blood perfusion of the kidney was normal and the flow singles could be seen at the site near to the renal capsule. Grade Ⅱ,the blood perfusion of the kidney was slightly abnormal and the flow singles could be seen in the renal cortex but not near to the capsule.Grade Ⅲ,the blood perfusion was heavily abnormal and the flow singles could not be seen in the renal cortex.Results The changes of renal hemodynamics and renal size began at T 3,peaked at T 5 and T 7,and returned to normal at T 9.The renal imaging of all rabbits were grade Ⅰ in CDPI and CDFI at T 0.In CDFI,all were grade Ⅲ at T 1～T 9,at T 11 and T 13 most of them only returned to grade Ⅱ,no one returned to grade Ⅰ.In CDPI, however, all were grade Ⅱ at T 1 and T 3, while only a few were grade Ⅲ at T 5 and T 7, and most have returned to grade Ⅰ at T 9.Conclusions During the period of ARF, two dimensional ultrasound is useful in showing the echo and measuring the depth of renal cortex. Spectrum Doppler is helpful in quantitatively analysing the renal hemodynamic changes. CDPI is more sensitive than CDFI in showing the blood perfusion of the kidney