[en] Full text: The aim of this prospective study was to compare doppler ultrasound (DU) and CR in the detection of renal artery stenosis (RAS) in hypertensive patients. 84 patients (24 M, 60 F, mean age 61 years) underwent renography (350 MBq ⁹⁹Tc^m-DTPA) 60 min after prehydration and 50 mg captopril oral]y or the patient's usual dose of ACE inhibitor. Dynamic and sequential images were obtained up to 20 min. A baseline study off ACE inhibitors was performed if the captopril study was abnormal. Renogram curves, time to peak (N < 5 min), mean cortical transit time (N < 4.5 min) and split function (N = 42-58%) were calculated. Studies were reported by two observers. DU was performed by a single experienced sonologist. Aortic and main renal artery velocities (N ratio<3), intra-renal arterial velocities (N<180 cm.s^-1), acceleration times (N < 0.07 s) and resistive indices (Δ < 0.05) were obtained when possible. The DU was considered technically adequate if the intra-renal indices could be obtained from both kidneys. Renal angiography was performed in 5 patients. DU and CR were concordant in 67 patients (79%), of whom 61 (72%) were normal. Angiography confirmed RAS in 3 patients with concordant, abnormal studies. In 6 patients (7%), the DU was technically inadequate. CR was incomplete in 3 patients (4%) who did not have a baseline study despite an abnormal captopril study. Eight patients had unilateral RAS by one test (4 DU, 4 CR), while the other test was normal. Angiography was performed in 2 of these patients and confirmed RAS in both (CR + /DU- and DU + /CR -). In conclusion, CR and DU have a high concordance rate in screening for RAS. Ultrasound provides additional anatomical information but has a higher rate of technical failures