title: Steady-state equilibrium phase inversion recovery ON-resonant water suppression (IRON) MR angiography in conjunction with superparamagnetic nanoparticles. A robust technique for imaging within a wide range of contrast agent dosages.
abstract: OBJECTIVE
  To investigate the ability of inversion recovery ON-resonant water suppression (IRON) in conjunction with P904 (superparamagnetic nanoparticles which consisting of a maghemite core coated with a low-molecular-weight amino-alcohol derivative of glucose) to perform steady-state equilibrium phase MR angiography (MRA) over a wide dose range.
  
  
  METHODS
  Experiments were approved by the institutional animal care committee. Rabbits (n = 12) were imaged at baseline and serially after the administration of 10 incremental dosages of 0.57-5.7 mgFe/Kg P904. Conventional T1-weighted and IRON MRA were obtained on a clinical 1.5 Tesla (T) scanner to image the thoracic and abdominal aorta, and peripheral vessels. Contrast-to-noise ratios (CNR) and vessel sharpness were quantified.
  
  
  RESULTS
  Using IRON MRA, CNR and vessel sharpness progressively increased with incremental dosages of the contrast agent P904, exhibiting constantly higher contrast values than T1 -weighted MRA over a very wide range of contrast agent doses (CNR of 18.8 ± 5.6 for IRON versus 11.1 ± 2.8 for T1 -weighted MRA at 1.71 mgFe/kg, P = 0.02 and 19.8 ± 5.9 for IRON versus -0.8 ± 1.4 for T1-weighted MRA at 3.99 mgFe/kg, P = 0.0002). Similar results were obtained for vessel sharpness in peripheral vessels, (Vessel sharpness of 46.76 ± 6.48% for IRON versus 33.20 ± 3.53% for T1-weighted MRA at 1.71 mgFe/Kg, P = 0.002, and of 48.66 ± 5.50% for IRON versus 19.00 ± 7.41% for T1-weighted MRA at 3.99 mgFe/Kg, P = 0.003).
  
  
  CONCLUSIONS
  Our study suggests that quantitative CNR and vessel sharpness after the injection of P904 are consistently higher for IRON MRA when compared with conventional T1-weighted MRA. These findings apply for a wide range of contrast agent dosages.
authors: University of Heidelberg, Department of Cardiology, Heidelberg, Germany.
authors: Gitsios
authors: G
authors: Gitsioudis
authors: Matthias
authors: M
authors: Stuber
authors: Ingolf
authors: I
authors: Arend
authors: Moritz
authors: M
authors: Thomas
authors: Jing
authors: J
authors: Yu
authors: Thomas
authors: T
authors: Hilbel
authors: Evangelos
authors: E
authors: Giannitsis
authors: Hugo A
authors: HA
authors: Katus
authors: Grigorios
authors: G
authors: Korosoglou
mesh_terms: D000438:Alcohols / Q000737:chemistry; D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology; D001013:Aorta, Thoracic / Q000473:pathology; D003287:Contrast Media / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D018810:Magnetic Resonance Angiography; D008280:Magnetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D015233:Models, Statistical; D008970:Molecular Weight; D015588:Observer Variation; D010316:Particle Size; D011817:Rabbits; D014867:Water / Q000737:chemistry
chemical_list: D000438:Alcohols; D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D014867:Water; C000499:ferric oxide; D007501:Iron; D005947:Glucose
keywords: blood-pool contrast agent; clinical dose; magnetic resonance angiography; off-resonance imaging (IRON MRA)