title: Accuracy of unenhanced magnetic resonance angiography for the assessment of renal artery stenosis.
abstract: OBJECTIVE
  To evaluate the accuracy of unenhanced magnetic resonance angiography (U-MRA) using balanced steady-state free precession (SSFP) sequences with inversion recovery (IR) pulses for the evaluation of renal artery stenosis.
  
  
  METHODS
  U-MRA was performed in 24 patients with suspected main renal artery stenosis. Two radiologists evaluated the quality of the imaging studies and the ability of U-MRA to identify hemodynamically significant main renal artery stenosis (RAS) defined as a stenosis ≥50% when compared to gold standard tests: contrast-enhanced magnetic resonance angiography (CE-MRA) (18 patients) or digital subtraction arteriography (DSA) (6 patients).
  
  
  RESULTS
  A total of 44 main renal arteries were evaluated. Of them, 32 renal arteries could be assessed with U-MRA. When CE-MRA or DSA was used as the reference standard, nine renal arteries had hemodynamically significant RAS. U-MRA correctly identified eight out of nine arteries as having ≥50% RAS, and correctly identified 22 out of 23 arteries as not having significant RAS, with a sensitivity of 88.8%, a specificity of 95.65%, positive and negative predictive value of 88.8% and 95.65%, respectively, and an accuracy of 93.75%. Renal artery fibromuscular dysplasia (FMD) was observed in the two misclassified arteries.
  
  
  CONCLUSIONS
  U-MRA is a reliable diagnostic method to depict normal and stenotic main renal arteries. U-MRA can be used as an alternative to contrast-enhanced magnetic resonance angiography or computer tomography angiography in patients with renal insufficiency unless FMD is suspected.
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Sebastià
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Alejandro D
authors.initials: AD
authors.lastname: Sotomayor
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Blanca
authors.initials: B
authors.lastname: Paño
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Salvador
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Burrel
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Botey
authors.affiliation: CDI, Department of Radiology and Nephrology, Hospital Clinic of Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Nicolau
keywords: Contrast-enhanced magnetic resonance angiography (CE-MRA); Fibromuscular dysplasia (FMD); Hypertension (HTA); Renal artery stenosis (RAS); Unenhanced magnetic resonance angiography (U-MRA)