Role of color Doppler ultrasound in the evaluation of renal transplantation from living donors

Purpose: The aim of this study was to evaluate the same kidney before and after transplantation to assess the ability of the allograft to restore blood flow, time required to achieve functional recovery after surgery and the possibility of differentiating normal from pathological allografts using color Doppler ultrasound (CDUS) flow indices: resistive index (RI)/renal cortical ratio (RCR) and scintigraphy. Materials and methods: 79 living donors and 79 recipients. Donors underwent renal CDUS and scintigraphy. CDUS was repeated on the allograft 24 h, 3, 15 and 30 days after transplantation, and scintigraphy 3-5 days after transplantation. Recipients were divided into two groups on the basis of clinical and biochemical values: (A) well-functioning allografts and (B) acute pathology. Results of CDUS, RI and RCI were compared to results of scintigraphy, biochemical values and biopsy. Results: Group (A) n = 60 (76 %), group (B) n = 19 (24 %); RI sensitivity was 93 %, specificity 83 %. In group (A) positive predictive value (PPV) was 94 % and in group (B) 90 %. RCR using receiver operating characteristic curve analysis yielded sensitivity 100 % and specificity 98.3 %. Scintigraphy mean values of glomerular filtration ratio and T max before transplantation were in group (A): 50.32 ml/min and 4.87 min; after transplantation 46.88 ml/min and 4.96 min; in group (B): 48.68 ml/min and 4.63 min, after transplantation 27.89 ml/min and 10.53 min, respectively. Pearson's correlation coefficient between preoperative and postoperative results of scintigraphy was significant in group (A) (glomerular filtration ratio = 0.85, T max = 0.70) and not significant in group (B) (glomerular filtration ratio = 0.40, T max = 0.08). Conclusion: This study shows that CDUS, RI and RCR are useful in postoperative evaluation of transplanted kidneys as these parameters can, after only 24 h, confirm the good condition of the allograft despite still excessive blood parameter values. © 2014 Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).