VISUALIZATION OF THE RENAL-ARTERIES AND VALUE OF COLOR-CODED DUPLEX SONOGRAPHY IN THE DETECTION OF RENAL-ARTERY STENOSIS USING AN ECHO ENHANCING AGENT

Purpose: To assess whether the use of an echo-enhancing agent reliably allows the diagnosis of renal artery stenosis with colour-coded Doppl er sonography. Materials and Methods: We examined the main, segmental, and, if present, the accessory renal arteries of 31 patients before a nd after intravenous injection of Levovist(R) using colour-coded Doppl er sonography and compared the results with digital subtraction angiog raphy. A rise in peak systolic velocity in the main renal artery and a reduction of the acceleration index in segmental arteries were used a s parameters to detect renal artery stenosis. Results: After i.v. admi nistration of Levovist(R) the main stem of the renal arteries could be well delineated in 36 of 62 cases (58%) during colour-coded Doppler s onography against 31 cases without Levovist(R). Taking only the visibl e cases in account the sensitivity of native as well as of enhanced co lour-coded Doppler sonography of the renal main !;tem was 100%, the sp ecificity was 96% and 94%, respectively. Only one of 11 accessory rena l arteries was identified after echo enhancement. The segmental arteri es were seen only after echo enhancement in 12 cases so that 60 of the total of 62 renal arteries (95%) could be evaluated. The sensitivity and specificity of the native examination were 67% and 70%. After echo enhancement sensitivity was 75% and specificity was 81%. Conclusion: Using an echo-enhancing agent the sensitivity and specificity for dete ction of relevant renal artery stenosis could only be slightly improve d compared to the native examination.