Value of non-contrast-enhanced MR angiography combined with captopril renal scintigraphy in the diagnosis of renovascular hypertension

Objective To evaluate the clinical value of non-contrast-enhanced MR angiography (NCE-MRA) combined with captopril renal scintigraphy (CRS) in the diagnosis of renovascular hypertension (RVH). Methods A total of 52 patients (33 males, 19 females; age: (54.5±16.3) years) with highly suspected RVH between January 2018 and October 2018 from Henan Provincial People′s Hospital were retrospectively analyzed. The examination data of NCE-MRA, basic renal dynamic imaging, CRS and digital subtraction angiography (DSA) were collected and reviewed. The renal artery stenosis (RAS) rate≥70% was the criterion for RVH diagnosed by DSA, which was considered as the gold standard. The diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of NCE-MRA, CRS and NCE-MRA+ CRS were determined. The consistency between NCE-MRA and DSA was analyzed by Kappa test. The differences of diagnostic efficiencies between CRS and NCE-MRA + CRS were compared by χ2 test or Fisher exact test. Results There was a high consistency between NCE-MRA and DSA in the diagnosis of RVH (Kappa=0.81, 95% CI: 0.62-0.96; P<0.01). The diagnostic sensitivity, specificity, accuracy, PPV and NPV of NCE-MRA were 88.89%(24/27), 92.00%(23/25), 90.38%(47/52), 92.31%(24/26), and 88.46%(23/26) respectively, those of CRS were 81.48%(22/27), 72.00%(18/25), 76.92%(40/52), 75.86%(22/29) and 78.26%(18/23) respectively, and those of NCE-MRA+ CRS were 74.07%(20/27), 100%(25/25), 86.54%(45/52), 100%(20/20) and 78.12%(25/32) respectively. Compared with CRS, the specificity (P=0.01) and PPV (P=0.03) of NCE-MRA+ CRS in the diagnosis of RVH were increased. Conclusion NCE-MRA and CRS are effective in the diagnosis of RVH, and the combination of two methods can significantly improve the diagnostic specificity and PPV than CRS alone. Key words: Hypertension, renovascular; Radionuclide imaging; Captopril; Technetium Tc 99m pentetate; Magnetic resonance imaging