Comparing diagnostic techniques of magnetic resonance angiography (MRA) and Doppler ultrasonography in determining severity of renal artery stenosis

BACKGROUND: Renal artery stenosis is one of the important causes of hypertension and end stage renal failure. Magnetic resonance angiography (MRA) and Doppler ultrasonography are non-invasive and safe diagnostic techniques that have also high sensitivity and specificity. Since the accuracy and reliability of these techniques depend upon technicians and softwares, we decided to evaluate and compare the sensitivity and specificity of these techniques in Isfahan. METHODS: Our study included all the patients (37 patients) who underwent renal artery angiography during 2 years from May 2003 to May 2005 and up to six months after that had underwent MRA (21 patients) and Doppler sonography (16 patients) in Isfahan. Renal artery angiography was considered as the gold standard. RESULTS: Sensitivity, specificity, positive and negative predictive values of 100%, 25%, 25%, and 100% were obtained for MRA respectively. Specificity and positive predictive values (PPV) of Doppler sonography were 67%. Its sensitivity and negative predictive values (NPV) were 57%. CONCLUSION: Although it seems that technician dependency, technical and software problems were the reasons of low specificity of gadolinium-enhanced MRA in our study, further studies with larger sample sizes are recommended.