title: Magnetic relaxation contrast agents in magnetization transfer imaging.
abstract: OBJECTIVE
  The effects of magnetic relaxation agents are explored in the context of magnetization transfer pulse sequences using cross-linked protein gels as modeled tissue systems.
  
  
  METHODS
  Magnetization transfer pulse sequences were used to study contrast agents that are designed to bind to rotationally immobilized protein targets.
  
  
  RESULTS
  The dynamic range available from contrast agents, used in conjunction with magnetization transfer pulse sequences, is comparable with or better than that based on spin-echo imaging sequences with short repetition times. Furthermore, useful changes in the intensity of water resonances may be achieved by using this combined approach even though the paramagnetic metal center may not have a free coordination position in the chelate complex for water molecule exchange.
  
  
  CONCLUSIONS
  The inclusion of magnetization transfer acquisition protocols in the context of magnetic imaging with contrast agents presents new opportunities for control of the information content of the image and for new classes of contrast agent structure and delivery.
authors.affiliation: Chemistry Department, University of Virginia, Charlottesville, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Danek
authors.forename: R G
authors.initials: RG
authors.lastname: Bryant
mesh_terms: D000818:Animals; D002417:Cattle; D003287:Contrast Media; D005682:Gadolinium; D019786:Gadolinium DTPA; D005782:Gels; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D017895:Manganese Compounds; D004369:Pentetic Acid; D019047:Phantoms, Imaging; D012710:Serum Albumin, Bovine; D013431:Sulfates
chemical_list: D003287:Contrast Media; D005782:Gels; D017895:Manganese Compounds; D013431:Sulfates; D012710:Serum Albumin, Bovine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA; C038958:gadolinium chloride; C039798:manganese sulfate