title: Correlation of proton transverse relaxation rates (R2) with iron concentrations in postmortem brain tissue from alzheimer's disease patients.
abstract: Iron accumulates in the Alzheimer's disease (AD) brain and is directly associated with beta-amyloid pathology. The proton transverse relaxation rate (R(2)) has a strong linear relationship with iron concentrations in healthy brain tissue; however, an independent test of this relationship has not been extended to AD brain tissue. In this study in vitro single spin-echo (SE) measurements were made on tissue samples from four human AD brains using a 4.7T MRI research scanner. R(2) values were calculated for 14 cortical and subcortical gray matter (GM) and white matter (WM) regions. Atomic absorption spectroscopy was used to measure iron concentrations in the corresponding excised brain regions. Significant positive linear correlations were observed between R(2) values and iron concentrations in GM regions assessed across individual tissue samples and data averaged by brain region. With the use of a predictive model for R(2), a threshold iron concentration of 55 microg Fe/g wet tissue was determined above which R(2) appears to be dominated by the affects of iron in AD brain tissue. High-field MRI may therefore be a useful research tool for assessing brain iron changes associated with AD.
authors.affiliation: School of Physics, University of Western Australia, Perth, Australia. mhouse@physics.uwa.edu.au
authors.forename: Michael J
authors.initials: MJ
authors.lastname: House
authors.forename: Timothy G
authors.initials: TG
authors.lastname: St Pierre
authors.forename: Kris V
authors.initials: KV
authors.lastname: Kowdley
authors.forename: Thomas
authors.initials: T
authors.lastname: Montine
authors.forename: James
authors.initials: J
authors.lastname: Connor
authors.forename: John
authors.initials: J
authors.lastname: Beard
authors.forename: Jose
authors.initials: J
authors.lastname: Berger
authors.forename: Narendra
authors.initials: N
authors.lastname: Siddaiah
authors.forename: Eric
authors.initials: E
authors.lastname: Shankland
authors.forename: Lee-Way
authors.initials: LW
authors.lastname: Jin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D007501:Iron / Q000032:analysis*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011522:Protons; D011859:Radiography
chemical_list: D011522:Protons; D007501:Iron