a To determine volumes of corpus callosum and intracranial volumes of Vietnamese normal adults. Subjects and methods: Analyzing volumes of corpus callosum and intracranial volumes from cranial magnetic resonance images taken from 455 Vietnamese healthy subjects (males 47.03%), and ranging in age from 17 to 87 years. Results: The total volume of corpus callosum was indifferent between genders (males: 3.40 ± 0.47 cm3 ; females 3.32 ± 0.44 cm3 ; p = 0.06), but volumes of rostrum, genu, and splenium regions were larger in males than those in females. The intracranial volume in females (1387.35 ± 96.72 cm3 ) was 10.76% smaller than that in males (1536.58 ± 103.46 cm3 ) (p < 0.001). The corpus callosum was getting smaller with ageing, which appeared in men more obviously and dispersedly at truncus and isthmus subregions, whereas in women that tendency was at central-truncus only. Conclusions: Findings from this morphological study on corpus callosum and intracranial volumes contributed to the reference anthropometric values of current Vietnamese adults using non-invasive imaging tools.
Trang 1MEASURING THE CORPUS CALLOSUM AND INTRACRANIAL VOLUMES OF VIETNAMESE NORMAL ADULTS USING
MAGNETIC RESONANCE IMAGING
Tong Quoc Dong 1 ; Nguyen Le Chien 1 ; Dang Tien Truong 1 Hoang Van Luong 1 ; Tran Hai Anh 1
SUMMARY
Objectives: To determine volumes of corpus callosum and intracranial volumes of Vietnamese normal adults Subjects and methods: Analyzing volumes of corpus callosum and intracranial volumes from cranial magnetic resonance images taken from 455 Vietnamese healthy subjects (males 47.03%), and ranging in age from 17 to 87 years Results: The total volume of corpus callosum was indifferent between genders (males: 3.40 ± 0.47 cm 3 ; females 3.32 ± 0.44 cm 3 ; p = 0.06), but volumes of rostrum, genu, and splenium regions were larger in males than those in females The intracranial volume in females (1387.35 ± 96.72 cm 3 ) was 10.76% smaller than that in males (1536.58 ± 103.46 cm 3 ) (p < 0.001) The corpus callosum was getting smaller with ageing, which appeared in men more obviously and dispersedly at truncus and isthmus subregions, whereas in women that tendency was at central-truncus only Conclusions: Findings from this morphological study on corpus callosum and intracranial volumes contributed to the reference anthropometric values of current Vietnamese adults using non-invasive imaging tools
* Keywords: Corpus callosum; Intracranial volume; Anthropometry; Vietnamese adults; MRI.
INTRODUCTION
With the development of modern
analytical techniques, methods for
evaluation of brain morphological
characteristics and their changes based
on magnetic resonance imaging (MRI)
have been being conducted at many
research centres abroad, and had also
attracted interest over the past decade in
Vietnam [2, 3] There have been
non-invasive studies using MRI in healthy
people as well as in people with brain
damaging diseases to investigate changes
of brain morphology, yet an issue on normal values of brain structures with age and sex in healthy adults is still open, raising a requirement for building-up reference ranges of brain structures with this novel imaging technique
Situating in the centre of the human brain consisting of approximately 200
250 million myelinated axons [7], the corpus callosum (CC) forms the largest commissural white matter bundle, connecting the hemispheres and brain cortical regions [9]
1 Vietnam Military Medical University
Corresponding author: Tran Hai Anh (anhhtr@yahoo.com)
Date received: 10/07/2019
Date accepted: 12/08/2019
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Therefore, changes in the brain structures
or functions in both physiological (age,
sex) or pathological states might affect
the CC and compromise this morphogical
structure The total intracranial volume
relates to hard tissue and relatively stable,
hence it has often been regarded as a
reference measurement for adjustment in
analyzing brain soft tissues, including the
CC [4]
From above mentioned issues, the
present study was conducted in order to:
Determine the corpus callosum and
intracranial volumes of Vietnamese normal
adults using MRI
SUBJECTS AND METHODS
1 Subjects
MRI were taken from 455 right-handed
Vietnamese adults (214 males, 19 - 82 years
old; 241 females, 17 - 87 years olds), who
visited the outpatient ward at 108 Military
Central Hospital from Nov 2017 to Nov
2018 They had no history of
neuro-psychiatric disorders or chronic diseases,
and had informed consent to participate in
the study Image data analysis and processing were performed at Department
of Physiology, Vietnam Military Medical University
2 Methods
* MRI procedure and analysis:
Three-dimensional brain scans were taken by a 1.5 Tesla MRI scanner system (Siemen, Germany), using the T1-weighted sagittal sequence with parameters: slice thickness 1 mm, TR = 15 ms, TE = 5 ms, NEX = 1 ms, flip angle = 30°, 25 x 25 cm FOV; matrix = 256 x 256, with more than
300 contiguous slices on each subject Brain image scans were then reviewed and confirmed by specialist physicians that of subjects having no damages of central nervous system The imaging data were stored in DICOM format, compressed
to NIFTI, rendering and analyzing for brain regions using FreeSurfer software version 6.0.0 [5] Volumetric values (cm3) of the total corpus callosum volume and its
subregions (figure 1) as well as intracranial
volume were taken into account
Figure 1: Corpus callosum and its subregion (Hampel et al, 1998 [6])
Trang 3* Data analysis:
Subjects were categorized by gender
and divided into 6 groups of age, ranging
from 17 to 87 years old The volumes of
total corpus callosum and its subregions
were compared among age groups within
sex by a co-variance analysis (ANCOVA);
the differences in age and the proportion
of subjects among groups were compared using the Student’s t.test and proportional comparisons (Chi-square tests) The analyses were made with SPSS 22.0 (IBM Inc., USA) and a significant difference was set as p value of less than 0.05
RESULTS
1 Demography of subjects
Table 1: Age and gender of subjects
Gender, n (%)
Age group
(n, X ± SD)
0.012
The results on table 1 showed no significant differences in mean age and the gender proportion of subjects However, the proportions of males and females among age groups were significantly different (p = 0.012) This difference can be attributed to the variety in the proportion of subjects by gender among groups of 45 - 54 and from
65 years old
Table 2: Corpus callosum and intracranial volumes (cm3) in both genders
Male
(x̅ ± SD)
Female
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Results in table 2 showed that though the total corpus callosum volume was indifferent between males and females, the volume of the rostrum-genu and splenium
of the corpus callosum in females were smaller than that of males (p = 0.002 and p = 0.004, respectively) The intracranial volume in females was also marked smaller than that in males (p < 0.001) The difference in intracranial volume between genders would have certain effects on the size and volume of internal brain structures Therefore, in evaluation of the corpus callosum volume in this study, the intracranial volume was regarded as a covariance
2 Change of corpus callosum volume by age groups
Table 3: Values of corpus callosum volumes (cm3) in males of age groups
Corpus
callosum
volumes
Total volume
Rostrum and genu
Anterior truncus
Central truncus
Posterior truncus and isthmus
Splenium
≤ 24
25 - 34
35 – 44
45 – 54
55 – 64
≥ 65
(The volume values shown were adjusted with the total intracranial volume)
Analyzing on males (table 3) showed that except for a might increase in volume of
the splenium even ageing, the corpus callosum continuously grew to about 35 - 44 years old and then began to shrink (p = 0.003) Moreover, the callosal shrinkage by ageing occurred mainly in the truncus and isthmus (included the anterior, p < 0.001; central, p < 0.001; posterior truncus and isthmus, p = 0.005)
Trang 5Table 4: Values of corpus callosum volumes (cm3) in females of age groups
Corpus
callosum
volumes
Total volume
Rostrum and genu
Anterior truncus
Central truncus
Posterior truncus and isthmus
Splenium
≤ 24
25 - 34
35 - 44
45 - 54
55 - 64
≥ 65
(The volume values shown after adjusted with the total intracranial volume)
In females, the shrinking phenomenon of the total corpus callosum as well as its
subregions was unobservable (p = 0.41), except for the central segment (p = 0.003) Moreover, the central volume also reached the peak value earlier than that in males, at the group “To 24”, and then gradually decreased with age
DISCUSSION
Anthropometrics of cranial sizes and
volumes of the Vietnamese population,
along with understandings of morphological
changes in functional brain regions aids in
determining normal ranges of values that
are references for studies on pathological
conditions in human However, negligence
of inter-individual variability of brain
structure and head size could cause
deviations in the determination of volumes
of brain structures [1] Several studies
analyzing volumes of brain regions on MRI
images of normal human showed that
intracranial volume in women was smaller than that in men Buckner et al (2014), by manually measuring intracranial volume, concluded that this volume was 10 - 20% greater in men than in women and it was minimally affected by age [4] Le Huu Hung (1995) also measured intracranial volume on the Vietnamese population and demonstrated that it was 8.43% greater in men than in women, with respective values of 1363.97 ± 103.2 cm3 and 1257.91 ± 92.2 cm3 [1] In this study, the total intracranial volume in men was 1536.58 cm3, which was 10.76% greater
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than that in women (1387.35 cm3) The
results reported by Le Huu Hung were
smaller than ours, which could be
attributable to the discrepancy in measuring
methods between two studies Our study
measured cranial size on MRI of alive
human while previous studies measured
on archaeological crania, which could have
shrunk due to dehydration after death or
in the process of cadaver preservation
Besides, changes in socio-economic status
between present and previous times
require more novel studies to establish
systematically reference ranges of human
anthropometrics
The present study analysed volume of
corpus callosum in both genders in
correlation with age and intracranial
volume Our results showed that corpus
callosum decreased in size at certain
ages, and more significantly and obviously
in men than in women In men, the corpus
callosum reached the peak at the age of
35 - 44 years old, then started to shrink
mainly at the truncus In women, the
corpus callosum did not present an obvious
change in total volume in adults and its
shrinkage was clearly observed only in
the central truncus Those findings were
different from many abroad studies on
volume of the corpus callosum
Takeda et al (2003) analysed several
indexes of the corpus callosum of
Japanese normal population in relation
with age by manually measuring on MRI,
which showed that changes occurred
mainly at the genu portion with no
difference between males and females
[10] Junle et al (2008) analysed biometric
indexes of the corpus callosum on
T1-weighted MRI of 286 healthy Chinese
from 20 to 86 years old found that among six regions of the corpus callosum, the length of the genu, 1/3 anterior, central and 1/3 posterior truncus, and splenium tended to declined over age [8] However, they noted a bigger volume of the corpus callosum in females than in males [8] Those inconsistencies may due to discrepancies in ethnics and measuring methods on MRI, and negligence of co-variants affecting intracranial volume in data analysis Another study by Prendergast
et al [9] on cranial MRI of 305 American adults showed that the corpus callosum developed maximally at the age of 32.2 for men and of 40.1 for women, which was consistent with our findings, but the decrement occurred mainly at the CC genu portion
CONCLUSIONS
Investigation on brain MRI showed that the intracranial volume of Vietnamese adults presently had different properties than those of previous studies, and the corpus callosum of the Vietnamese people also had compromised traits differed from those of other ethnicities and races Therefore, our findings in the present study contributed to the anthropometrics reference of current Vietnamese adults
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