[Color-coded duplex sonography of dysfunctional kidney transplants. Correlation of the resistive index with the histopathologic results of biopsy].

The resistive index (RI) is used as a measure of the vascular resistance in renal allografts. The sample volume for the measurement can be positioned much more exactly with color duplex US than with duplex US, resulting in more precise values for the RI. To find out which pathologic changes lead to an increase of the RI, we correlated the RI with the histopathological results obtained in 43 biopsies. Our results show that it is not possible to differentiate between vascular and interstitial rejection on the basis of the RI because there is no statistically significant difference between the RI values caused by the two types of rejection. Distinct interstitial infiltration, edema of any origin, vascular changes and also chronic rejection and arteriolosclerosis lead to elevated RI. A good correlation was found between the elevation of RI and the severity of the vascular changes. Severe tubular and glomerular changes, cyclosporine toxicity, tubular necrosis, cytomegaly infection, glomerulonephritis and dysfunctions of other causes did not lead to elevation of the RI.