Assessment of renal artery stenosis: comparison of captopril renography and gadolinium-enhanced breath-hold MR angiography.
OBJECTIVE
To determine the accuracy of captopril renography (CR) and gadolinium-enhanced breath-hold magnetic resonance (MR) angiography in the diagnosis of 50-99% renal artery stenosis (RAS).


METHODS
Forty-three patients with possible RAS, of whom 53% had renal function impairment (creatinine >130 micromol/l), were included.(99m)Tc-mercaptoacetyl triglycine (MAG(3)) renography was performed after an oral dose of 25 mg captopril. Gadolinium-enhanced MR angiography was performed on a standard 1.5 Tesla system: TR 13.5, TE 3.5, flip angle 60 degrees, matrix 195 x 512. Intra-arterial digital subtraction angiography (DSA) was the standard of reference.


RESULTS
Captropril renography accurately categorized 22 of 26 patients who had either uni- or bilateral RAS of 50-99%. The sensitivity and specificity of CR for the detection of 50-99% stenosis were 85 and 71%, respectively. With MR angiography one occluded artery was incorrectly diagnosed as a stenosis. Sensitivity and specificity were 100 and 94%, respectively. The difference between the accuracies of MR angiography and CR was statistically significant (P = 0.02). The accuracy of CR was lower in patients with renal impairment (70%) than in those with normal renal function (90%).


CONCLUSIONS
MR angiography showed a high accuracy in diagnosing RAS of between 50 and 99%. CR was less accurate than MR angiography, especially in patients with renal function impairment. In patients with normal renal function, however, CR remains a useful diagnostic test.
Bongers
V
V
Department of Nuclear Medicine, University Hospital Utrecht, The Netherlands.
Bakker
J
J
Beutler
J J
JJ
Beek
F J
FJ
De Klerk
J M
JM
D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity
D000806:Angiotensin-Converting Enzyme Inhibitors; D003287:Contrast Media; D002216:Captopril; D019786:Gadolinium DTPA