Diffusion tensor imaging of cingulum fibers in mild cognitive impairment and Alzheimer disease.
BACKGROUND
Neuroimaging in mild cognitive impairment (MCI) and Alzheimer disease (AD) generally shows medial temporal lobe atrophy and diminished glucose metabolism and cerebral blood flow in the posterior cingulate gyrus. However, it is unclear whether these abnormalities also impact the cingulum fibers, which connect the medial temporal lobe and the posterior cingulate regions.


OBJECTIVE
To use diffusion tensor imaging (DTI), by measuring fractional anisotropy (FA), to test 1) if MCI and AD are associated with DTI abnormalities in the parahippocampal and posterior cingulate regions of the cingulum fibers; 2) if white matter abnormalities extend to the neocortical fiber connections in the corpus callosum (CC); 3) if DTI improves accuracy to separate AD and MCI from healthy aging vs structural MRI.


METHODS
DTI and structural MRI were preformed on 17 patients with AD, 17 with MCI, and 18 cognitively normal (CN) subjects.


RESULTS
FA of the cingulum fibers was significantly reduced in MCI, and even more in AD. FA was also significantly reduced in the splenium of the CC in AD, but not in MCI. Adding DTI to hippocampal volume significantly improved the accuracy to separate MCI and AD from CN.


CONCLUSIONS
Assessment of the cingulum fibers using diffusion tensor imaging may aid early diagnosis of Alzheimer disease.
Zhang
Y
Y
MR Unit (114M), VA Medical Center, 4150, Clement Street, San Francisco, CA 94121, USA. Yu.Zhang@ucsf.edu
Schuff
N
N
Jahng
G-H
GH
Bayne
W
W
Mori
S
S
Schad
L
L
Mueller
S
S
Du
A-T
AT
Kramer
J H
JH
Yaffe
K
K
Chui
H
H
Jagust
W J
WJ
Miller
B L
BL
Weiner
M W
MW
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000145:classification / Q000175:diagnosis*; D003072:Cognition Disorders / Q000145:classification / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D020534:Parahippocampal Gyrus / Q000473:pathology