Valerie C. Anderson1, David P. Lenar1,
Joseph F. Quinn2, William J. Woodward3, Jeffrey A. Kaye2,
William D. Rooney3
1Neurological Surgery, Oregon Health
& Science University, Portland, OR, United States; 2Neurology,
Oregon Health & Science University, Portland, OR, United States; 3Advanced
Imaging Research Center, Oregon Health & Science University, Portland,
OR, United States
Longitudinal
water proton (1H2O) relaxation time constants (T1)
are strongly associated with macromolecular volume fraction. Here, we report
that 1H2O T1 values are increased in the
thalamus of subjects with early AD compared to age-matched, cognitively
normal controls. Further, we find that the increased 1H2O
T1 values in early AD reflect, at least in part, neurodegenerative
(macromolecular loss) processes and
that contributions to the increased 1H2O T1
values from altered blood water content (via dilation or increased vessel
density) are small.