Quantitative evaluation of acute renal failure in rabbits with contrast-enhanced ultrasound.

Background Assessment of perfusion in the early period of acute renal failure (ARF) is important, and can not be made by conventional ultrasound. The aim of this study was to prospectively test in a rabbit ARF model whether real-time contrast-enhanced ultrasound (CEUS) can quantitatively evaluate the hemodynamic changes of renal cortex in the early period. Methods The model of ARF was induced in 30 healthy New Zealand white rabbits (2.5-3.0 kg), by intramuscular injection of 50% glycerin solution (12 ml/kg). CEUS were performed on right kidneys before, 6 and 24 hours after glycerin injection. CEUS quantitative indexes were measured in renal cortex using QLAB software. Comparisons between different stages were performed using paired t test. The sensitivity of CEUS in diagnosing ARF was compared with blood serum urea nitrogen (BUN), serum creatinine (SCr) level and color Doppler flow imaging (CDFI). Results Among quantitative indexes, time to peak (UP) and area under curve (AUC) increased significantly from (5.86 +/- 2.57) seconds and (124.4 +/- 46.7) dB.s before glycerin injection to (7.66 +/- 2.05) seconds and (288.1 +/- 64.9) dB.s 6 hours after injection (P <0.05). Slope rate of ascending curve (A) and descending curve (a) decreased slightly from (3.00 +/- 1.22) dB/s and (0.19 +/- 0.15) 1/s to (2.80 +/- 1.45) dB.s and (0.09 +/- 0.02) 1/s (P <0.05). Twenty-four hours later, only AUC increased significantly from (124.4 +/- 46.7) dB.s to (466.2 +/- 52.2) dB.s (P <0.05). Conclusion Quantitative indexes of CEUS might be useful in predicting the hemodynamic changes of renal cortex in the early six hours of ARF model. Chin Med J 2012;125(4):652-656