Using Doppler sonography to reveal renal artery stenosis: An evaluation ofoptimal imaging parameters

OBJECTIVE. The aim of this study was to determine the accuracy of direct an d indirect parameters for the diagnosis of renal artery stenosis and to det ermine the most useful thresholds for these parameters. SUBJECTS AND METHODS. One hundred twenty-five arteries in 63 patients were examined with renal Doppler sonography and angiography for the presence or absence of renal artery stenosis. Arteries were considered stenosed on angi ography if there was a diameter reduction of greater than 60%. Renal Dopple r sonographic measures of peak systolic velocity renal aortic ratio, accele ration time, and acceleration were recorded and compared with the angiograp hically determined presence or absence of disease. RESULTS. Doppler examination was technically successful in 87% of kidneys a nd 76% of patients. Receiver operating characteristic analysis showed the o ptimal peak systolic velocity threshold to be 180 cm/sec and the optimal re nal aortic ratio threshold to be 3.0. An acceleration time greater than 70 msec and an acceleration less than 300 cm/sec(2) yielded sensitivities of 4 1% and 56% respectively, and specificities of 85% and 62%, respectively. Co mbining a renal aortic ratio of greater than 3.0 or peak systolic velocity greater than 180 cm/sec provided the best combination of parameters with a sensitivity and sensitivity at 85% and 76%, respectively. CONCLUSION. The most accurate use of parameters was found to be a combinati on of either peak systolic velocity greater than 180 cm/sec or renal aortic ratio greater than 3.0. Indirect parameters were not found to be useful in predicting the presence or absence of renal artery stenosis.