Postoperative haemodynamic changes in transplanted liver: Long-term follow-up with ultrasonography.

OBJECTIVE: To investigate haemodynamic changes in the transplanted liver without postoperative complications. METHODS: Colour Doppler ultrasound was used to monitor recipients of liver transplants who had no postoperative complications. The haemodynamic data for the hepatic vasculature were compared at different time-points during the first 4 years after liver transplantation. RESULTS: A total of 144 liver transplant patients were enrolled in the study. Portal vein flow velocity decreased significantly from 72.1 ± 30.3 cm/s at 1 day to 44.2 ± 20.1 cm/s at 1 month after liver transplantation. Hepatic artery flow velocity was 61.4 ± 33.2 cm/s at day 1; it then decreased slowly but significantly to 48.3 ± 20.4 cm/s at 3 years after transplantation. There were 81 (56.3%) patients with high hepatic artery resistance index (HARI) (>0.80) and 19 (13.2%) with low HARI (<0.50) measured at least once during the 4-year follow-up examination. CONCLUSIONS: Decreased portal vein flow velocity was the typical change observed during the first month after liver transplantation. Abnormal haemodynamic Doppler results should be interpreted with caution because they may not be clinically significant and may improve spontaneously.

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 (TTP) 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.

[Quantitative evaluation of contrast-enhanced ultrasound in the early diagnosis of acute renal failure of rabbits].

OBJECTIVE: To evaluate the early diagnostic value of contrast-enhanced ultrasound (CEUS) in acute renal failure (ARF) of rabbit. METHODS: The rabbit model of ARF was established by intramuscular injection of 50% glycerin (12 ml/kg) into the hind legs of 18 New Zealand rabbits. CEUS was performed for both kidneys before injection and 6 hours after the injection. The slope rate of ascending curve (A), the slope rate of descending curve (alpha), area under curve (AUC), derived peak intensity (DPI), and time to peak (TTP) were measured in renal cortex of rabbits using Q-lab software package. Blood serum urea nitrogen (BUN) and serum creatinine (SCr) were measured. RESULTS: The values of A and alpha before the injection of glycerin were (3.07 +/- 1.83) dB/s and (0.19 +/- 0.15)/s, respectively, which were significantly higher than the values after injection [ (2.76 +/- 1.31) dB/s and (0.09 +/- 0.02)/s, respectively] (P < 0.05). The values of AUC and TTP before the injection of glycerin were (137.4 +/- 68.4) dB s and (6.33 +/- 3.71) s, which were significantly lower than the values after injection [(309.5 +/- 88.9) dB s and (8.61 +/- 3.97) s, respectively] (P < 0.01). No significant change of DPI, BUN or SCr was found. CONCLUSIONS: CEUS can precisely display the hemodynamic change of ARF model of rabbit in the early stage, with superior sensitivity than BUN and SCr. It may be a promising imaging method for the early diagnosis of ARF.