Diffusion abnormality in posterior cingulate fiber tracts in Alzheimer's disease: tract-specific analysis.
OBJECTIVE
The aim of this study was to determine diffusion abnormalities in the posterior cingulate fiber tracts (PCFTs) in patients with Alzheimer's disease (AD) by diffusion tensor tractography (DTT).


METHODS
We studied 23 AD patients and 18 age-matched normal controls who underwent magnetic resonance imaging using diffusion tensor imaging (DTI). DTT of PCFTs was generated from DTI. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in co-registered voxels along with DTT of PCFTs. Student's t-test was used to compare results between the AD patients and normal controls.


RESULTS
The MD in PCFTs was significantly higher in AD patients than in normal controls (P = 0.019). The FA in PCFTs was significantly lower in AD patients than in normal controls (P = 0.007).


CONCLUSIONS
The abnormal MD increase and FA decrease, which is considered to indicate a net loss of barriers that restrict water molecular motion and tissue anisotropy of white matter, is consistent with neuropathological data that demonstrate partial loss of myelin, axons, and oligodendrial cells in white matter of AD brains. Our results suggest that MD and FA reflect progression of AD-related histopathological changes in the PCFTs and may represent a useful biological index for monitoring AD.
Nakata
Yasuhiro
Y
Department of Radiology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. nakatay-tky@umin.ac.jp
Sato
Noriko
N
Abe
Osamu
O
Shikakura
Shoko
S
Arima
Kunimasa
K
Furuta
Nobuo
N
Uno
Masatake
M
Hirai
Shigeo
S
Masutani
Yoshitaka
Y
Ohtomo
Kuni
K
Aoki
Shigeki
S
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism*; D016880:Anisotropy; D001369:Axons / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006179:Gyrus Cinguli / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000378:metabolism / Q000473:pathology; D009836:Oligodendroglia / Q000378:metabolism / Q000473:pathology; D011712:Pyramidal Tracts / Q000378:metabolism / Q000473:pathology; D012720:Severity of Illness Index