title: In vivo Na-23 MR imaging and spectroscopy of rat brain during TmDOTP5- infusion.
abstract: In vivo sodium-23 and hydrogen-1 magnetic resonance (MR) imaging and spectroscopy of the rat brain during infusion of the shift reagent thulium DOTP5- (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra[methylene phosphonate] was performed to assign the various peaks observed during infusion and to evaluate the shift reagent in discriminating tissue compartments. Na-23 spectra collected during the infusion showed two shifted peaks that were assigned to intravascular Na+ and extracellular muscle Na+, respectively, and one unshifted peak assigned to intra- and extracellular brain Na+ and cerebrospinal fluid Na+. These assignments were validated with H-1 and Na-23 MR imaging and Na-23 chemical shift imaging (CSI). The H-1 and Na-23 images showed that a surface coil placed on a rat head can detect a substantial amount of signal from muscle surrounding the skull. Na-23 CSI spectra from successive 1-mm-thick coronal sections indicated that the shift reagent did not cross the blood-brain barrier. The study also showed that bulk susceptibility shifts are quite small with Tm-DOTP5-. This reagent may be useful in determining compartmental Na+ concentrations and blood flow kinetics in brain and in examining the integrity of the blood-brain barrier.
authors.affiliation: Mary Nell and Ralph B. Rogers Magnetic Resonance Center, Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-9085.
authors.forename: N
authors.initials: N
authors.lastname: Bansal
authors.forename: M J
authors.initials: MJ
authors.lastname: Germann
authors.forename: I
authors.initials: I
authors.lastname: Lazar
authors.forename: C R
authors.initials: CR
authors.lastname: Malloy
authors.forename: A D
authors.initials: AD
authors.lastname: Sherry
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D051381:Rats; D011919:Rats, Inbred Strains; D012975:Sodium Isotopes; D013932:Thulium
chemical_list: D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D012975:Sodium Isotopes; C069929:thulium(III) 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetramethylenephosphonate; D013932:Thulium