Magnetic Resonance Angiography Versus Duplex Sonography for Diagnosing Renovascular Disease

Abstract

Abstract-Noninvasive testing for renovascular disease is required to identify patients who may benefit from revascularization procedures without exposing an unnecessary amount of patients to the risks of catheter angiography. All available methods of diagnosing renal artery stenosis have significant limitations. We compared a new technique, contrast-enhanced magnetic resonance angiography, with an established technique, duplex ultrasonography, for the detection of renal artery stenosis using catheter angiography as the standard of reference. Eighty-nine patients with clinically suspected renovascular disease underwent duplex renal scanning and contrast-enhanced magnetic resonance angiography. Sixty of these also underwent catheter angiography. All studies were interpreted for the presence of renal artery stenosis blinded to the results of the other imaging modalities. For detection of hemodynamically significant (Ն60% diameter reduction) main renal artery stenosis, sensitivity and specificity were 90% and 86%, respectively, for magnetic resonance angiography and 81% and 87% for duplex sonography. Most false readings involved differential grading of stenoses detected with all 3 techniques. When patients with fibromuscular dysplasia were excluded from the analysis, the sensitivity of magnetic resonance angiography increased to 97%, with a negative predictive value of 98%. Magnetic resonance angiography detected 96% and duplex 5% of accessory renal arteries seen at catheter angiography. Contrast-enhanced magnetic resonance angiography is a useful technique for diagnosing atherosclerotic renovascular disease. It overcomes the major limitations of duplex renal scanning. However, duplex has the advantage of providing hemodynamic information and appears better suited for the assessment of patients with suspected fibromuscular dysplasia. (Hypertension. 1999;33:726-731.)

The STARD Statement for Reporting Studies of Diagnostic Accuracy: Explanation and Elaboration

“…A test result may be invalidated by a concomitant medical condition or therapy that affects the test, e.g., the effect of beta-adrenergic blockers on heart rate response during an exercise test (indeterminant result) (24 ). (50 ) Since variability is the rule rather than the exception, researchers should explore possible sources of heterogeneity in results, within the limits of the available sample size. The best practice is to plan subgroup analyses before the start of the study (84 ).…”

“…They did not specify whether they planned this subgroup analysis before the data collection. (50 ) We recommend that authors report all measures of test reproducibility that they performed during the study (see Item 13). For quantitative analytical methods, report the coefficient of variation (CV) at concentrations that are relevant to the study, state those concentrations and the number of determinations (for within-run CV, if relevant) or the number of days of testing (for day-to-day, total CV), or both.…”

Congenital Solitary Kidney With Renovascular Hypertension Diagnosed by Means of Captopril-enhanced Renography and Magnetic Resonance Angiography

“…The sensitivity and specificity of MRA for the detection of hemodynamically significant stenosis of the main renal artery were reported to be around 90%. 11,12) However, MRA is less reliable for the diagnosis of FMD, and duplex utrasonography seems more suit-Vol 46 No 2 able for the assessment of patients with suspected FMD. 11) In our patient, the combination of captopril renography and MRA proved to be an effective screening method to detect RVHT.…”

Renal Denervation: Unde Venis et Quo Vadis?

“…As in the HNT-1 and HTN-2 trial, the follow-up methodology for detecting renal artery stenoses again is problematic since only Doppler ultrasound was performed to detect renal artery stenoses [50]. Doppler ultrasound has a significantly lower sensitivity and specificity compared to CT and MR angiography [72,73]. The extent to which this result would change in the case of corresponding follow-up via MR or CT angiography is currently speculative.…”