Color Doppler sonography in early renal transplantation follow-up: resistive index measurements versus power Doppler sonography.

OBJECTIVE: This study was designed to compare power Doppler images of perfusion with interlobar resistive index measurements obtained during the early monitoring of renal graft transplant to diagnose cortical perfusion abnormalities and assess prognosis. SUBJECTS AND METHODS: Thirty-one patients underwent color Doppler sonography (4-7 MHz and 7-10 MHz) on day 6+/-2 after renal transplantation. Cortical vessel density was assessed visually and classified as either normal or decreased. Twelve months after transplantation, the results of power Doppler imaging and the levels of resistive index were reviewed in light of clinical and laboratory findings, graft biopsy results, and functional outcome. RESULTS: No significant relationship was observed among power Doppler grades, levels of resistive index, and renal function. Power Doppler grades and resistive index levels failed to allow us to distinguish between tubulopathy and rejection. However, we found a statistically significant relationship between renal function at 12 months after transplantation and power Doppler grade (p = .04). CONCLUSION: This study suggests that color Doppler sonography is insensitive in revealing and in allowing radiologists to differentiate the causes of graft dysfunction. However, power Doppler sonography allows a prediction of the functional recovery of the graft at 12 months after transplantation not provided by resistive index levels.