Grey-matter volume as a potential feature for the
classification of Alzheimer’s disease and mild cognitive
impairment: An exploratory study
Yan’e Guo 1, Zengqiang Zhang 1,2, Bo Zhou 1, Pan Wang 1, Hongxiang Yao3,
Minshao Yuan4, Ningyu An3, Haitao Dai2, Luning Wang 1, Xi Zhang1, Yong
Liu5,6
1Department
of Neurology, Institute of Geriatrics and Gerontology, Chinese
PLA General Hospital, Beijing 100853, China
2Hainan
Branch of Chinese PLA General Hospital, Sanya 572014, China
3Department
of Radiology, Chinese PLA General Hospital, Beijing 100853,
China
4Department
of Neurology, the People’s Hospital of Jimo, Qingdao 266200,
China
5Brainnetome
Center, Institute of Automation, Chinese Academy of Sciences,
Beijing 100190, China
6National
Laboratory of Pattern Recognition, Institute of Automation, Chinese
Academy of Sciences, Beijing 100190, China
Corresponding
authors:
Xi
Zhang
and
Yong
Liu.
E-mail:
zhangxi@301hospital.com.cn, yliu@nlpr.ia.ac.cn
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Fig. S1. Whole-brain voxel-wise analyses between groups. A-C: Brain areas with
significant atrophy in aMCI patients compared to NC individuals (A); AD compared
to aMCI patients (B); and AD patients compared to NC individuals (C). In all cases, P
<0.001, cluster size >40 voxels, uncorrected.
Fig. S2. Subregion segmentation. The left hippocampus was isolated based on the
AAL template using the WFU_PickAtlas toolkit (www.ansir.wfubmc.edu) [1] and
included 20 slices (at y-axis) from the head to the tail and 932 voxels (resolution 2
mm×2 mm×2 mm). Next, we divided these 20 slices into 4 equal parts. The voxel
numbers for the head, body 1, body 2, and tail were 264, 202, 265, and 201,
respectively. The right hippocampus and the bilateral parahippocampus were
subdivided in the same manner. A and B illustrate the parcellations of the bilateral
hippocampus and parahippocampus. C: The gray-matter volumes of these
subdivided regions were significantly decreased in AD (grey bar) compared to NC
groups (white bar). *P <0.05 (FDR-corrected).
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Fig. S3. ROC curves of the leave-2-to-5-out analyses to classify participants with AD
and NC using the linear discrimination analysis method. A: We randomly removed 2
participants who formed the test group and examined the remaining 60 as the
training group. This cross-validation step was performed 1770 (60×59/2) times. The
average proportion of correct classifications between the AD and NC participants
was 82.3%. B-D: Similarly, we randomly removed 3-to-5 participants as test datasets
and performed 10,000 cross-validations; the mean correct ratio was ~83%. AUC,
area under the curve; correct ratio, percentage of participants correctly classified
out of the total number of participants.
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Fig. S4. The same cross-validation procedure was used to distinguish the AD, aMCI,
and NC groups. A-D: ROC curves showing that the leave-2-to-5-out analyses
resulted in classification of NC (blue), aMCI (red), and AD (black) participants when
linear discrimination analysis was used. AUC, area under the curve; correct ratio,
percentage of participants correctly classified out of the total number of
participants.
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Fig. S5. Brain areas with significant grey matter atrophy in AD patients compared to
NC individuals. A: left hemisphere. B: right hemisphere (P <0.001, FWE corrected,
cluster size >40 voxels). Further details on these regions are in Table S1.
Table S1. Regions with significantly reduced gray-matter volume in AD patients
compared to normal controls
Region
BA
Cluster size
T value
Z value
MNI Coordinates
Hip/Phip.L
28/34
362
10.94
8.34
-28
-12 -16
(x,y,z)
7.38
6.17
-20 -22 -14
6.84
5.83
-26 2 -22
9.43
7.31
26 -10 -16
7.51
6.25
38 -30 -12
Hip/Phip.R
28/34
386
STG/MTG.L
21/22
246
8.96
7.07
-56 -38 -4
Hip/Phip.R
30
82
8.10
6.60
20 -36 0
Hip/Phip.L
27
67
7.69
6.36
-20 -36 -2
Two-sample, two-tailed t-tests with age and gender as covariants. The threshold for the
resultant T-value map was chosen to be P <0.001 [T = 5.89, df = (1, 58), FWE-corrected]
for each voxel with a cluster size of at least 40 voxels. Phip, parahippocampus; BA,
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Brodmann’s area; Hip, hippocampus; MTG, middle temporal gyrus; L, left; R, right; STG,
superior temporal gyrus.
REFERENCES
[1] Ledberg A, Akerman S, Roland PE. Estimation of the probabilities of 3D
clusters in functional brain images. Neuroimage 1998, 8: 113-128.
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