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Advanced Neurology Cortical thickness and regional homogeneity in CSVD

Monte Carlo simulation correction with a vertex-wise/ for differences in age and education. Bonferroni correction
cluster-forming threshold of 3 (P < 0.001) and a cluster- was applied in the GLM for post hoc multiple comparison
wise P < 0.001 (two tailed). The cortical thicknesses of corrections. Partial correlation analysis was conducted to
significant brain regions were extracted for further study. explore the relationships between MRI parameters and
cognitive scale scores, with age and education as covariates.
2.5. fMRI data P < 0.05 was considered to indicate statistical significance.
2.5.1. Preprocessing of fMRI 3. Results

The fMRI analysis was based on the BOLD sequence.
DPARSF, a method based on the Resting-State Functional 3.1. Clinical assessments
MR Imaging Toolkit (http://www.restfmri.net) and Demographically, there was no difference in sex among
statistical parametric mapping software package (SPM12; the CSVD-CI group, CSVD-no-CI group, and NC group.
www.fil.ion.ucl.ac.uk/spm), was used for the preprocessing However, both of the CSVD groups were older than the
of fMRI data. The preprocessing steps included removing NC group, and the CSVD-CI group had fewer years
the first 10 volumes of data, slice timing correction, of education than the other two groups. There was no
realignment, reorientation, head motion correction (note significant difference in Fazekas scores, lacunar infarcts
that participants with head motion more than 2.0 mm of count, and microbleeds between the CSVD-CI group and
displacement in any direction, or 2.0° of rotation in any the CSVD-no-CI group. In terms of vascular risk factors,
angular dimension were excluded), image segmentation there was a significant difference in hypertension, but
for the high-resolution T1-weighted turbo gradient echo no significant differences in diabetes, hyperlipidemia,
sequence and the BOLD sequence by Diffeomorphic and smoking. In neuropsychological evaluation, there
Anatomical Registration Through Exponentiated Lie were significant differences in HAMD and VRIR scores
algebra, coregistration of T1 images to the functional between the CSVD-no-CI group and the NC group. Post
images, normalization using a 12-parameter non-linear hoc multiple comparisons were performed among the
transformation to the standard Montreal Neurological CSVD-CI group, CSVD-no-CI group, and NC group.
Institute (MNI) space (3 × 3 × 3 mm ), and band-pass Detailed information regarding the clinical assessments is
3
filtering (0.01–0.08 Hz). shown in Tables 1-3.
2.5.2. ReHo analysis 3.2. Cortical thickness analysis
The purpose of the fMRI analysis was to explore the There were significant differences in cortical thickness
functional changes of certain brain regions that were among the CSVD-CI group, CSVD-no-CI group, and
extracted from the structural analysis. The significant brain NC group in the left insula, right insula, right anterior
regions in cortical thickness analysis were transferred into cingulate gyrus (ACG), right cuneus, and right middle
MNI space and defined as regions of interest (ROIs) in temporal gyrus (MTG). Post hoc multiple comparisons
ReHo analysis. The ReHo analysis using the preprocessed were performed among the CSVD-CI group, CSVD-
fMRI data was also performed by DPARSF. The steps for no-CI group, and NC group, adding age and education as
acquiring the ReHo value after z-translation and smoothing covariates. Detailed information for the cortical thickness
were as follows: (1) Calculating the ReHo value of 27 voxels analysis is shown in Figure 1, Tables 4 and 5. The CSVD-CI
and doing a Z-transform, (2) smoothing the ReHo map group exhibited lower cortical thickness in all five regions
after Z-transform with a Gaussian kernel of 6 mm FWHM compared with that in the other two groups, and the
for noise reduction, and (3) extracting ReHo values of the CSVD-no-CI group exhibited lower cortical thickness only
ROIs for further statistical analysis. in the bilateral insula and the right MTG compared with
that in the NC group.
2.6. Statistical analysis
The demographic data were analyzed using SPSS 16.0 3.3. ReHo analysis
(SPSS, Chicago, IL, USA). All of the continuous variables The five brain regions exhibiting group differences in
were tested for normality before comparison. Analysis of cortical thickness analysis were targeted as the ROIs
variance (ANOVA) and the Kruskal–Wallis test were used in ReHo analysis. ReHo values of ROIs were extracted,
to compare the variation in age, education, and cognitive followed by GLM analysis (adding age and education
scale scores among the three groups according to normality. as covariates, using Bonferroni correction for post hoc
A Chi-squared test was used for the comparison of sex multiple comparisons). There were significant differences
and vascular risk factors among groups. Changes in ReHo in ReHo values of the left insula (P = 0.005) and right
across groups were analyzed using the GLM, controlling insula (P = 0.024) among the CSVD-CI group, CSVD-

Volume 1 Issue 1 (2022) 4 https://doi.org/10.36922/an.v1i1.48