title: Use of a blood-pool contrast agent for MR-guided vascular procedures: feasibility of ultrasmall superparamagnetic iron oxide particles.
abstract: OBJECTIVE
  The purpose of this study was to examine the dose dependency of the intravascular signal intensity after injection of ultrasmall superparamagnetic iron oxide (USPIO) particles (SH U 555 C) in a rabbit model studied with a low-field-strength magnetic resonance (MR) imaging system. The results were used to facilitate MR-guided vascular procedures in a pig.
  
  
  METHODS
  All experiments were performed at 0.2 T. To determine the optimum USPIO (or SH U 555 C) dose for intravascular interventions, the authors acquired coronal three-dimensional MR angiographic images in 12 rabbits after injection of four dose levels (10, 20, 30, and 40 micromol of iron per kilogram body weight). The intraaortic signal intensities were measured in user-defined regions of interest. For numerical analysis, signal intensity enhancement was computed. Subsequently MR image-guided procedures were performed in USPIO-enhanced vessels in one pig.
  
  
  RESULTS
  The signal intensity evaluation shows a clear-cut dose dependence in both early and late phases after administration of SH U 555 C. A high-spatial-resolution MR angiogram acquired 20 minutes after injection yielded the best results with the highest dose (40 micromol of iron per kilogram); at that dose, intravascular enhancement was sufficient for vascular procedures for 60 minutes after injection.
  
  
  CONCLUSIONS
  SH U 555 C is a promising contrast agent for MR angiography and MR-guided vascular procedures in an open low-field-strength MR imager.
authors.affiliation: Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, OH 44108, USA.
authors.forename: Frank K
authors.initials: FK
authors.lastname: Wacker
authors.forename: Michael
authors.initials: M
authors.lastname: Wendt
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ebert
authors.forename: Claudia
authors.initials: C
authors.lastname: Hillenbrandt
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Wolf
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Lewin
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage*; D003911:Dextrans; D004305:Dose-Response Relationship, Drug; D005240:Feasibility Studies; D052203:Ferrosoferric Oxide; D007089:Image Enhancement / Q000379:methods*; D007501:Iron / Q000008:administration & dosage*; D018810:Magnetic Resonance Angiography; D058185:Magnetite Nanoparticles; D023421:Models, Animal; D010087:Oxides / Q000008:administration & dosage*; D011817:Rabbits; D012815:Signal Processing, Computer-Assisted; D013552:Swine
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide