[Color Doppler ultrasound of kidney transplants. Does the resistance index facilitate diagnosis of chronic kidney failure?].

The retrospective study under report assessed the diagnostic capability of colour Doppler sonography (CDS) with measurement of the resistive index (RI) in the long-term follow-up of patients with renal allografts. 210 CDS examinations were performed in 115 patients. The time since transplantation ranged from 6 months to 22 years. The RI was correlated to laboratory parameters of renal allograft function (serum creatinine, urinary protein levels and serum-cyclosporine). In 97 of 210 examinations, serum creatinine was elevated (> 1.5 mg% or an increase of more then 0.3 mg% within the last 6 months). In 35 out of these examinations RI was > 70%, in 62 RI was < or = 70%. Thus, with a threshold RI of 70%, sensitivity of the RI in the diagnosis of renal allograft dysfunction is 36% and specificity 62%, respectively. There was no significant difference in the RI between examinations of allografts with normal function (68.2% +/- 7.5%) and those with dysfunction (68.5% +/- 8.5%). Furthermore, there was no significant correlation between the RI and any of the laboratory parameters. CDS with calculation of the RI cannot differentiate in the long-term follow-up between allografts with normal function and those with dysfunction.