1.4T study of proton magnetic relaxation rates, iron concentrations, and plaque burden in Alzheimer's disease and control postmortem brain tissue.
We measured proton magnetic longitudinal (R(1)) and transverse (R(2)) relaxation rates at 1.4T, iron concentrations, water contents, and amyloid plaque densities in postmortem brain tissue samples from three Alzheimer's disease (AD), two possible AD, and five control subjects. Iron concentrations and R(1) were significantly higher in the temporal cortex region of our AD group compared to the controls. Frequency analyses showed that the observed trends of higher iron, R(1), and R(2) in AD gray matter regions were statistically significant. Simple regression models indicated that for AD and control gray matter the iron concentrations and water contents have significant linear correlations with R(1) and R(2). Multiple regression models based on iron concentrations and water contents were highly significant for all groups and tissue types and suggested that the effects of iron become more important in determining R(1) and R(2) in the AD samples. At 1.4T R(1) and R(2) are strongly affected by water content and to a lesser extent by variations in iron concentrations. The AD plaque density did not correlate with iron concentrations, water contents, R(1), or R(2), suggesting that increases in AD brain iron are not strongly related to the accumulation of amyloid plaques.
School of Physics, University of Western Australia, Perth, WA 6009, Australia. mhouse@physics.uwa.edu.au
Michael J
MJ
House
Timothy G
TG
St Pierre
Catriona
C
McLean
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology*; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D007501:Iron / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D058225:Plaque, Amyloid
D007501:Iron