title: Effect of injection rate on contrast-enhanced MR angiography image quality: Modulation transfer function analysis.
abstract: Contrast-enhanced (CE)-MRA optimization involves interactions of sequence duration, bolus timing, contrast recirculation, and both R1relaxivity and R2*-related reduction of signal. Prior data suggest superior image quality with slower gadolinium injection rates than typically used.
  
  
  
  A computer-based model of CE-MRA was developed, with contrast injection, physiologic, and image acquisition parameters varied over a wide gamut. Gadolinium concentration was derived using Verhoeven's model with recirculation, R1and R2* calculated at each time point, and modulation transfer curves used to determine injection rates, resulting in optimal resolution and image contrast for renal and carotid artery CE-MRA. Validation was via a vessel stenosis phantom and example patients who underwent carotid CE-MRA with low effective injection rates.
  
  
  
  Optimal resolution for renal and carotid CE-MRA is achieved with injection rates between 0.5 to 0.9 mL/s and 0.2 to 0.3 mL/s, respectively, dependent on contrast volume. Optimal image contrast requires slightly faster injection rates. Expected signal-to-noise ratio varies with both contrast volume and cardiac output. Simulated vessel phantom and clinical carotid CE-MRA exams at an effective contrast injection rate of 0.4 to 0.5 mL/s demonstrate increased resolution.
  
  
  
  Optimal image resolution is achieved at intuitively low, effective injection rates (0.2-0.9 mL/s, dependent on imaging parameters and contrast injection volume). Magn Reson Med 78:357-369, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Radiology, University of Colorado Denver, Aurora, Colorado, USA.
authors.forename: Toshimasa J
authors.identifier: 0000-0003-4058-5632
authors.initials: TJ
authors.lastname: Clark
authors.affiliation: Radiology, University of Washington, Seattle, Washington, USA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wilson
authors.affiliation: Radiology, University of Washington, Seattle, Washington, USA.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Maki
mesh_terms: D001158:Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D005682:Gadolinium / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005682:Gadolinium
keywords: MR angiography; Modulation transfer function; contrast injection rate