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AND TRAINING DEFENCEVIETNAM MILITARY MEDICAL UNIVERSITY ---PHAM THANH NGUYEN RESEARCH ON MORPHOLOGICAL CHARACTERISTICS OF THALAMUS AND CONNECTION OF THALAMUS – CORTEX IN MRI OF HUMAN BR

AND TRAINING DEFENCE

VIETNAM MILITARY MEDICAL UNIVERSITY

-PHAM THANH NGUYEN

RESEARCH ON MORPHOLOGICAL CHARACTERISTICS

OF THALAMUS AND CONNECTION OF THALAMUS – CORTEX IN MRI OF HUMAN BRAIN OF HEALTHY

VIETNAMESE ADULTS

SPECIALITY: BIOMEDICAL SCIENCE

CODE: 9720101

SUMMARY OF THESIS

Full name of supervisors:

1 Associate Prof Dr Lam Khanh

2 Prof Dr Nguyen Duy Bac

The first opponent: Prof Dr Pham Minh Thong

The second opponent: Associate Prof Dr Ngo Xuan Khoa The third opponent: Associate Prof Dr Do Duc Cuong

The thesis will be protected before the Board of thesis review at Military Medical University at ……… a.m/ p.m on…………,2021

The thesis can be found at:

1 National Library

2 Library of Military Medical University

The thalamus is a complex of gray nuclei located in the brain.Recent advances in neural imaging technology have given new insightsinto the anatomical structure of the human brain and are changinghuman understanding of the hippocampus It is now possible todifferentiate subnuclear structures to examination of functionalconnections of different areas of the brain through functional magneticresonance imaging (fMRI), through studies of the brain in autopsy orthrough animal experiments

Investigating the anatomical links in one brain region and amongbrain regions helps us to understand the functional activities and thecoordination of functional activities of those brain regions Research hasbeen conducted on animals using noninvasive methods to learn aboutthe conduction tracts (bundles) in the brain, but studies involvingpathways in the human brain are very limited Injecting fluorescentpigments after autopsy allows the transmission bands (bundles) to beidentified but only seen at distances about 10 millimeters With furtherlinks may be determined by large bundle anatomy or histological study

of distal degeneration following a localized lesion, but such studies arebased on a relatively small number of The patient has no information.The creation of nerve path images by Diffusion Tensor Imaging -DTI is based on anisotropic diffusion of water molecules in the axons DTI

is a new and modern technique that provides full awareness of theconnections in the brain In addition, recent developments in diffuse tensionmagnetic resonance imaging have enabled us to determine the pathways ofthe bands (bundles), mainly in the living brain

The image of sensory pathways through the thalamus connecting

to brain regions is very important in clinical practice and has not beenstudied in Vietnam

The objectives of the study are to:

1 Describe the morphological features of the thalamus on the 3.0 tesla magnetic resonance image in healthy Vietnamese adults.

2 Determine morphological characteristics of the thalamus cortex on the 3.0 tesla DTI image in healthy Vietnamese adults.

-Practical meaning and further contributions

This thesis provides data of the changes in length, width, height

as well as the volume of the right and left thalamus on the 3.0 MRIfilms in ordinary Vietnamese adults At the same time, this thesis alsoidentifies morphological characteristics: length, number of fibers, FA,ADC of the thalamocortical tracts on magnetic resonance diffusiontensor imaging (DTI) 3.0 in ordinary Vietnamese adults These arevaluable scientific data of morphological characteristics of the thalamusand the thalamocortical tracts on MRI 3.0 images in normal Vietnameseadults This is the first study in Vietnam to apply a new and moderntechnique, which helps to fully understand the links in the brain, therecent development in magnetic resonance diffusion tensor imagingtechniques helps us to determine the path of the tracts (bundles), mainly

in the living brain

STRUCTURE OF THE THESIS

The thesis includes: 129 pages

Question: 2 pages; Overview: 38 pages; Research subjects andmethodology: 18 pages; Research results: 37 pages; Discussion:

31 pages; Conclusion: 2 pages; Recommendation 1 pages

The thesis also has 40 Tables, 7 Charts, 35 Figures; 141References (1 in Vietnamese and 140 in English)

CHAPTER 1 LITERATURE REVIEW

1 Anatomical and functional characteristics of the thalamus

1.1 Anatomical characteristics of the thalamus

1.1.1 Outline

The thalamus, shaped like an egg, is the two largest gray nuclei ofthe central gray nuclei and is a major component of the medial cerebrum,together with the hypothalamus forming the side of the thirdinterventriculare The boundary between the two regions is marked by afurrow (hypothalamus) that runs from the foramen interventriculare to theaperture aqueductus cerebri In most individuals, the bilateral thalamus isconnected through the thin slit of the third ventricle by adhesioninterthalamica, also known as the gray edge

1.1.2 Outward form of the thalamus

The thalamus is ovoid, with large heads facing back, the largeaxis facing forward, inward, and slightly upwards, with the large axis onthe opposite side at an angle of about 60 °, extending backwards Thethalamus are about 3cm long, 2cm high, 1.5cm thick, with 4 sides:inside, outside, back (upper), abdomen (bottom); 2 heads: front, back;and 3 shores are more or less identified: the inner upper shore, the outerupper shore and the inner lower shore

1.1.3 The inner form of the thalamus

1.1.4 The role of the thalamus

The thalamus is the main transition station to the cortex, described as a

"gateway" to the cortex Almost everything we can know about the outside world, or about ourselves, is based on information passing through the thalamus.

1.1.4.1 Environmental awareness is an activity related to the thalamus 1.1.4.2 The importance of the cerebral cortex - thalamus - cortex for perception 1.1.4.3 Perception to act or action to perceive? Parallel processing of sensory and motor signals

1.2 Neurotransmitters

1.2.1 Sensory nerve pathways

1.2.1.1 Outline of the sensory neurotransmitters

1.2.1.2 Somatic sensory pathways posterior column – medial lemniscus

The Dorsal Column-Medial Lemniscal Pathway

The dorsal column-medial lemniscal pathway (DCML) carriesthe sensory modalities of fine touch (tactile sensation), vibration andproprioception There are three groups of neurones involved in thispathway – first, second and third order neurones

First Order Neurones

Second Order Neurones

Third Order Neurones

1.2.1.3 Unconscious Sensation

Posterior spinocerebellar tract

Anterior spinocerebellar tract

1.2.1.4 The Anterolateral System

First Order Neurones

Second Order Neurones

Third Order Neurones

1.2.2 Descending motor pathways

is equivalent in all directions, that is, water diffuses freely However, inwhite matter diffuses in a directional way, also known as anisotropic.Due to the structural properties and delineation of myelin in thebundles of nerve fibers, the water molecules in these bundles areconfined diffuse along the axons of the bundle of nerve fibers.Therefore, DTIs are used to identify and characterize the white matter'sconduction bundles and thus can provide researchers with the properties

of the connection pathways in the brain

1.3.2 DTI applications in brain structure research

1.3.3 Some methods and initial application of DTI in determining the structural features and nuclei of the thalamus

1.3.4 Determination of the connections of the thalamus to the cortex using DTI

1.3.5 DTI applications in research on the thalamus and neurotransmitters in Vietnam

So far, with the available documents, we have only seen the work ofauthors Nguyen Tri Dung, Pham Ngoc Hoa, and Cao Thien Tuong in 2010studying the use of DTIs in distinguishing brain abcess from necrotic braintumors in capsule form There is no research study on morphologicalcharacteristics of the hippocampus and the connections of the thalamuswith regions of the cerebral cortex by this technique

CHAPTER 2 SUBJECTS AND METHODS 2.1 Participants and data acquisition

2.1.1 Location and duration of research

This thesis was conducted at the Imaging Department of the108th Military Central Hospital, from June 2015 to December 2016

2.1.2 Subjects of study

This study used data sets and methods of analyzing and filmingcranial CHT films of 50 normal people, aged 18 years and older,without any brain diseases or neurological damage

- Criteria for selecting research subjects

Select the subject without any skull abnormalities; history orcurrently traumatic brain injury, any diseases that cause central nervousdamage such as Alzheimer's, brain tumors, or any neurological, psychiatricand chronic neurological diseases All research subjects were MRI capturedwith basic pulse sequences and DTI pulses

- Exclusion criterias

Subjects are excluded from the research if they have one of thediseases such as central neurological damage pathologies, for example,Alzheimer's, brain tumors, or neurological, psychiatric and chronicneurological diseases

2.3 Research indicators

2.3.1 General characteristics of the research participants

General characteristics: Age, gender

2.3.2 Morphology of thalamus on MRI 3.0 tesla

The length of the right and left thalamus (mm)

The width of the right and left thalamus (mm)

The height of the right and left thalamus (mm)

The volume of the right and left thalamus (ml)

2.3.3 Morphology of thalamocortical sensory tract on DTI 3.0 tesla

- The number of branches of thalamocortical tracts on the 3D image

- The length of thalamocortical tracts on the 3D image

The right and left thalamocortical tracts’ dimensions on 3D images:

- Types of thalamocortical tract graphs (divided in 2, 3, 4, 5, 6 branches and branches to the opposite side when connected to thecerebral cortex).

- FA, ADC values of thalamocortical tracts on 3D image

Analyzes the linear correlation between X and Y variables with astandard distributionwith a Pearson correlationnumber

CHAPTER 3 RESULTS 3.1 Age and gender characteristics of research subjects

Table 3.1 Statistics on age groups, gender and the corresponding

distributions of research subjects

n(%)

n(%)

n(%)

6(12)

50(100)

3.2 Morphological characteristics of the thalamus

3.2.1 General characteristics of the size and volume of the thalamus

Table 3.2 General characteristics of the sizes and the volume of the

thalamus subjects in study (n = 50)

3.2.2 Characteristics of the thalamus length

Bảng 3.3 Comparison of the left and right mean length of the thalamus

Table 3.3 shows that the length of the left thalamus in male is 31.30

mm, which is 30.92 mm larger than the length of the left thalamus infemale, but there is no difference that is statistically significant with p>0,05 The length of the right thalamus for men is 31.38 mm, greater thanthe length of the right thalamus for women is 31.05 mm, but there is nodifference with p> 0,05 The mean lengths of the right and left thalamus(31.23 mm and 31.12 mm) were not statistically significant with p> 0.05

3.2.3 Characteristics of the thalamus width

Table 3.5 Comparison of the left and right medium width of the

Table 3.5 shows that the width of the left thalamus in men tends

to be greater than the width of the thalamus in women, but thisdifference is not statistically significant with p> 0.05 However, thewidth of the right thalamus for men is 16.74 mm, larger than the width

of the right thalamus for women, 16.16 mm, which is statisticallysignificant with p <0.05 The width of the thalamus on both sides is alsosimilar: left (16.46 mm) and right (16.46 mm) with p = 0.979

3.2.4 Height characteristics of the thalamus

Table 3.7 Compare the average height on the right and left sides of the

mm respectively The height of the thalamus on the left (16.77 mm)corresponds to the right (16.79 mm) with p = 0.946

3.2.5 Volumetric characteristics of the thalamus

Table 3.9 Comparision between the left and right volumes of the

of the thalamus volume on the left and the number on the right is 6.43

ml Consequently, the volume of the thalamus in both sides arerelatively similar The total volume of the thalamus is 12.86 ml

3.3 Morphological characteristics of the thalamus - cortex

3.3.1 Characteristics of the size of the thalamus - cortex

3.3.1.1 Characteristics of the length of the cortical thalamus

Table 3.20 Length of the thalamus - cortex

p < 0.05

Table 3.21 Compare the average length of the thalamocortical tracts by

gender on both sides

Gender The average length of the

Table 3.21 shows the average length of the thalamocortical tracts between left and right in females is 118,94 mm and 127,85 mm

respectively The female's average length of the thalamocortical tracts

on the right is longer than the left, a statistically significant result with(p < 0,05) The male’s average length of the thalamocortical tracts onthe left is 123,32 mm and the right is132,32 mm; which mean theaverage length of the thalamocortical tracts on the right is longer thanthe left - a statistically significant result with (p < 0,05)

3.3.1.2 The morphological characteristics about the number of thalamocortical tracts’s fibers

Table 3.23 The number of fibers's the left and right thalamocortical

p > 0.05 the number of fibers of thalamocortical tracts’s male in the left

is 295,5 fibers and in the right is 401,5 fibers The number of fibers of

the thalamocortical tracts in the left is lower than the right which is notstatistically significant with p > 0.05.

Median value about the number of fibers of thalamocorticaltracts in the left is 315 fibers, in the right is 401,5 fibers; The number offibers of the thalamocortical tracts in the right is higher than the left butthe difference is not statistically significant, with p > 0,05

Table 3.24 Compare the average length of the

thalamocortical tractson the right and the left in gender (fibers)

The thalamocortical tracts

Male (n = 26)

Female (n = 24)

Average (n = 50)

pMedian

value

Medianvalue

MedianvalueNumber of fibers on the left 295,50 347,00 315,00 0,396Number of fibers on the right 401,50 398,50 401,50 0,777

Comment:

Table 3,24’s result shows the number of fibers on the rightside is almost the same for both gender, while the number of male'sfibers on the left side is lower than female but the difference is notstatistically significant, with p > 0,05

3.3.2 Morphological forms of the thalamocortical tracts

Table 3.30 Statistics of the number and distribution of branching

morphologies of the thalamocortical tracts

Table 3.30 results show that the thalamocortical tracts’ branchesare polymorphism In which, the group of 4 branches accounts for 42%,the group of 3 branches accounts for 25%, the group of 5 branchesaccounts for 16%, the group of 6 branches accounts for 12% and theleast group of 2 branches accounts for 5% From the image we can seeshows that there are branches with equal proportions on the right andleft, each accounting for 50%

3.3.3 Characteristics of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the thalamocortical tracts

3.3.3.1 Characteristics of fractional anisotropy (FA) of the

3.3.3.2 Characteristics of apparent diffusion coefficient (ADC) of the thalamocortical tracts.