title: MRI gradient fields increase brain mannitol space.
abstract: Following nephrectomy and intravenous injection of tritiated mannitol, adult male rats were exposed to magnetic resonance imaging (MRI) procedures at 1.5 T, 0.5 T, and 0.3 T. Compared to rats similarly handled but not exposed to MRI procedures, brain mannitol concentration, expressed as a percentage of mean body concentration, was significantly increased at 0.3 T and 0.5 T but not at 1.5 T. At 0.3 T, exposure to gradient-field fluctuations used for imaging increased brain mannitol concentration, but exposures to static main field and pulsed radiofrequency energies did not. Increased brain mannitol associated with gradient-field flux may reflect increased blood-brain barrier permeability or blood volume in brain. MRI effects on brain mannitol space are of uncertain clinical significance, but are consistent with prior evidence of an MRI-induced increase of brain capillary endothelial cell transport observed with horseradish peroxidase. Further studies are needed to confirm these findings and to explore the processes underlying changes in mannitol distribution related to MRI.
authors.affiliation: Department of Psychiatry, UCLA School of Medicine.
authors.forename: H J
authors.initials: HJ
authors.lastname: Garber
authors.forename: W H
authors.initials: WH
authors.lastname: Oldendorf
authors.forename: L D
authors.initials: LD
authors.lastname: Braun
authors.forename: R B
authors.initials: RB
authors.lastname: Lufkin
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000378:metabolism*; D004574:Electromagnetic Fields / Q000009:adverse effects; D055590:Electromagnetic Phenomena; D008279:Magnetic Resonance Imaging / Q000009:adverse effects; D008297:Male; D008353:Mannitol / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008353:Mannitol