The use of duplex Doppler ultrasonography to evaluate renal allograft dysfunction.

This study evaluated the utility of duplex Doppler sonograms (DS) and the resistive index (RI) in the identification and differential diagnosis of various causes of renal allograft dysfunction. The efficacy of DS and RI was studied either during acute episodes of allograft dysfunction or during periodic posttransplantation longitudinal analyses. The unique features of each renal allograft results in poor correlative value for single isolated measurements of RI. We observed that the highest RIs were in ATN and that an RI of 0.9 was not specific for acute vascular rejection. Also, an RI of 0.9 was rare in acute cellular rejection. RI could not distinguish acute rejection, chronic rejection, CsA toxicity, or obstruction, although the mean RI was significantly different from normal in these groups. Serial studies of RI did document a change at the time of a clinical event compared to baseline. It is concluded that RI is not specific to any one clinical entity.