title: Enhancing fMRI contrast in awake-behaving primates using intravascular magnetite dextran nanopartieles.
abstract: Functional MRI in awake-behaving primates is an emerging tool for bridging the gap between human fMRI and neurophysiology information from nonhuman primates. We report the use of magnetite dextran nanoparticles (Feridex) as a blood-pool agent to enhance fMRI contrast-to-noise (CNR) in primate FMRI. The intravascular half-life of the magnetite dextran was long compared to lanthanide chelates (T(1/2) = 198 min) with shortened T(2) relaxation observed in blood and cerebral cortex. Greater than 3-fold enhancement in the percentage MR signal change was observed using nanoparticles (13%) compared with conventional BOLD fMRI (4%). The calculated regional cerebral blood volume in macaque primary visual cortex increased 32% with photic stimulation. The increased CNR allows greater flexibility in the design of awake-behaving primate fMRI studies with the potential for improvements in resolution and significantly shortened imaging times.
authors.affiliation: Division of Biology, 216-76, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Dubowitz
authors.forename: K A
authors.initials: KA
authors.lastname: Bernheim
authors.forename: D Y
authors.initials: DY
authors.lastname: Chen
authors.forename: W G
authors.initials: WG
authors.lastname: Bradley
authors.forename: R A
authors.initials: RA
authors.lastname: Andersen
mesh_terms: D000818:Animals; D001364:Awareness; D001522:Behavior, Animal; D002560:Cerebrovascular Circulation / Q000502:physiology; D003287:Contrast Media / Q000493:pharmacokinetics*; D003911:Dextrans / Q000493:pharmacokinetics*; D052203:Ferrosoferric Oxide; D007501:Iron / Q000493:pharmacokinetics*; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010087:Oxides / Q000493:pharmacokinetics*; D014793:Visual Cortex / Q000502:physiology*
chemical_list: D003287:Contrast Media; D003911:Dextrans; D010087:Oxides; D007501:Iron; D052203:Ferrosoferric Oxide