title: Manganese enhancement in non-CNS organs.
abstract: Manganese-enhanced magnetic resonance imaging (MEMRI) is a novel imaging technique capable of monitoring calcium influx, in vivo. Manganese (Mn2+) ions, similar to calcium ions (Ca2+), are taken up by activated cells where their paramagnetic properties afford signal enhancement in T(1)-weighted MRI methodologies. In this study we have assessed Mn2+ distribution in mice using magnetization-prepared rapid gradient echo (MP-RAGE) based MRI, by measuring changes in T(1)-effective relaxation times (T(1)-eff), effective R(1)-relaxation rates (R(1)-eff) and signal intensity (SI) profiles over time. The manganese concentration in the tissue was also determined using inductively coupled plasma atomic emission spectrometry (ICP-AES). Our results show a strong positive correlation between infused dose of MnCl2 and the tissue manganese concentration. Furthermore, we demonstrate a linear relationship between R(1)-eff and tissue manganese concentration and tissue-specific Mn2+ distribution in murine tissues following dose-dependent Mn2+ administration. This data provides an optimized MnCl2 dose regimen for an MP-RAGE based sequence protocol for specific target organs and presents a potential 3D MRI technique for in vivo imaging of Ca2+ entry during Ca2+-dependent processes in a wide range of tissues.
authors.affiliation: Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Hammersmith Hospital Campus, Imperial College London, London, UK.
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Lee
authors.forename: Po-Wah
authors.initials: PW
authors.lastname: So
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Price
authors.forename: James R C
authors.initials: JR
authors.lastname: Parkinson
authors.forename: David J
authors.initials: DJ
authors.lastname: Larkman
authors.forename: Jane
authors.initials: J
authors.lastname: Halliday
authors.forename: Simon M
authors.initials: SM
authors.lastname: Poucher
authors.forename: John A T
authors.initials: JA
authors.lastname: Pugh
authors.forename: Alan G
authors.initials: AG
authors.lastname: Cox
authors.forename: Cameron W
authors.initials: CW
authors.lastname: McLeod
authors.forename: Jimmy D
authors.initials: JD
authors.lastname: Bell
mesh_terms: D000818:Animals; D002712:Chlorides / Q000008:administration & dosage / Q000378:metabolism; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008345:Manganese / Q000737:chemistry / Q000378:metabolism; D017895:Manganese Compounds / Q000008:administration & dosage / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D014018:Tissue Distribution
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D008345:Manganese; C025340:manganese chloride