title: Direct CSF injection of MnCl(2) for dynamic manganese-enhanced MRI.
abstract: MnCl(2) was injected intrathecally through the cisterna magna in rats, allowing infusion of divalent manganese ions (Mn(++)) into the CSF space and thence into the brain, without breaking the blood-brain barrier (BBB). Mn(++) uptake and washout dynamics in the brain were measured by serial T(1)-weighted MRI and EPI T(1) and T(2) mapping for up to 3 weeks after injection. Observations within the first 6 hr after injection demonstrated anterograde and bilateral distribution of the Mn(++) within the CSF space, from the olfactory bulb and frontal cortex to the brain stem. Enhancement increased in most brain areas up to 4 days after injection, and then slowly decreased. Relaxation maps at each time point demonstrated higher concentrations of Mn in basal ganglia. Residual concentrations were still observable after 3 weeks in all brain regions. With the use of MnCl(2) calibration phantoms, the maximum Mn concentration in the brain was estimated to be approximately 27 +/- 16 microM, corresponding to changes in relaxation rates of 0.49 +/- 0.30 s(-1) for R(1) and 3.9 +/- 2.4 s(-1) for R(2). For comparison, an intrathecal GdDTPA injection was performed. This injection showed different distribution dynamics: it remained chiefly within the CSF spaces, and was largely washed out after 1 day. This method shows promise as a means of supplying Mn(++) uniformly to the whole brain for a variety of chronic functional activation studies.
authors.affiliation: Department of Radiology, MGH-NMR Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Christina H
authors.initials: CH
authors.lastname: Liu
authors.forename: Helen E
authors.initials: HE
authors.lastname: D'Arceuil
authors.forename: Alex J
authors.initials: AJ
authors.lastname: de Crespigny
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D002712:Chlorides / Q000008:administration & dosage* / Q000378:metabolism; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007278:Injections, Spinal; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008345:Manganese / Q000032:analysis; D017895:Manganese Compounds / Q000008:administration & dosage* / Q000378:metabolism; D019047:Phantoms, Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D008345:Manganese; D019786:Gadolinium DTPA; C025340:manganese chloride