Power Doppler versus color Doppler imaging in renal allograft evaluation.

The purpose of this study was to evaluate the impact of PDS compared to conventional CDI in the followup of 72 renal allograft patients. Renal allograft vascularization, assessed by PDS and CDI, was scored from 0 to 4, where 0 was the cortical "blush" and 4 was residual central perfusion. These scores were correlated with the resistive index, serum creatinine levels, hematocrit, and, in 35 cases, biopsy results. PDS scores of renal perfusion were one grade lower than CDI scores in 59 of 72 patients and two grades lower in two of 72 patients. A statistically significant correlation was found between PDS scores and the RI (r2 = 0.6, P < 0.05). However, no significant correlation was found between PDS scores and creatinine levels or hematocrit values. PDS scores are not related to histologic findings in renal allograft dysfunction. Overall, five biopsy-related arteriovenous fistulas were detected, two of which were missed on the initial PDS examination. In conclusion, PDS provides more complete visualization of the renal allograft vessel tree than CDI. However, biopsy-related arteriovenous fistulas are better seen by CDI.