A Prospective Comparison of Duplex Ultrasonography, Captopril Renography, MRA, and CTA in Assessing Renal Artery Stenosis

Purpose: To prospectively compare the diagnostic accuracy of duplex ultrasonography, captopril renography, computed tomography angiography (CTA), and 3D Gd magnetic resonance angiography (MRA) in diagnosing hemodynamically significant renal artery stenosis (RAS). Material and Methods: The standard of reference was measurement of transstenotic pressure gradient. Fifty-eight hypertensive patients with suspicion of RAS were evaluated, when possible, by all five techniques. Sensitivity and specificity to detect RAS were compared for each technique on both a patient and kidney basis. Discrepancies were evaluated separately and classified as borderline, method dependent, or operator dependent. Results: The prevalence of RAS was 77%. The sensitivity specificity of ultrasonography, captopril renography, CTA, and MRA in detecting kidneys with RAS was 73 71%, 52 63%, 94 62%, and 93 91%, respectively. Ultrasonography had a significantly lower sensitivity than CTA and MRA (P