Efficacy and safety of gadobutrol-enhanced MRA of the renal arteries: Results from GRAMS (Gadobutrol-enhanced renal artery MRA study), a prospective, intraindividual multicenter phase 3 blinded study

J Magn Reson Imaging. 2018 Feb;47(2):572-581. doi: 10.1002/jmri.25774. Epub 2017 Jun 2.

Abstract

Purpose: To compare the performance of magnetic resonance angiography (MRA) with 1M gadobutrol, a high relaxivity macrocyclic contrast agent, to 2D time-of-flight MRA (ToF-MRA) using computed tomographic angiography (CTA) as the standard of reference. Primary objectives were evaluation for superiority of structural delineation and noninferiority for detection and exclusion of clinically significant disease.

Materials and methods: In all, 315 subjects underwent unenhanced and contrast-enhanced MRA with 1M gadobutrol (CE-MRA) and were scanned with 1.5T MRI equipped with an at least 6-element body coil. Evaluations were based on both centralized blinded read (BR) performed by six readers as well as investigator site interpretations for the 292 subjects who completed the study. Quantitative evaluations including percent stenosis and normal vessel measurements were also performed. Secondary endpoints included identification of accessory renal arteries, diagnosis of fibromuscular dysplasia (FMD), diagnostic confidence, and need for additional imaging.

Results: A total of 292 patients suspected of renal artery disease completed the study. CE-MRA demonstrated statistically significant improvement in assessability of vascular segments compared to ToF: 95.9% vs. 77.6% (P < 0.0001). In the BR, the sensitivity and specificity of CE-MRA were noninferior to ToF-MRA (53.4% vs. 46.6% and 95.1% vs. 85.7%, respectively). There was less error in the CE-MRA stenosis measurements (0.15 mm gadobutrol vs. 0.41 mm ToF, P < 0.05). FMD was correctly diagnosed more frequently, 10% more accessory renal arteries were identified (P < 0.01), diagnostic confidence increased (P < 0.01), and fewer additional imaging studies were recommended (P < 0.01).

Conclusion: Gadobutrol-enhanced MRA of the renal arteries has superior visualization, more accurate vessel measurements, and may serve as a CTA alternative without any ionizing radiation.

Level of evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:572-581.

Keywords: contrast-enhanced MRA; gadobutrol; renal artery stenosis; time-of-flight MRA.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Contrast Media*
  • Female
  • Humans
  • Image Enhancement / methods*
  • Magnetic Resonance Angiography / methods*
  • Male
  • Middle Aged
  • Organometallic Compounds*
  • Prospective Studies
  • Renal Artery / diagnostic imaging*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Single-Blind Method
  • Vascular Diseases / diagnostic imaging*
  • Young Adult

Substances

  • Contrast Media
  • Organometallic Compounds
  • gadobutrol