Summary of the thesis: Estimating pyramidal tract lesions and some diffusion tensor imaging indexs related to motor function in ischemic stroke patients

Aim of the thesis: Describe the imaging characteristics of the neural tract lesions in DTI inischemic stroke patients compared to normal people. Estimate the relation between some DTI indexs to motor function in ischemic stroke patients.

108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES

VU DUY LAM

ESTIMATING PYRAMIDAL TRACT LESIONS AND SOME DIFFUSION TENSOR IMAGING INDEXS RELATED TO MOTOR FUNCTION IN

ISCHEMIC STROKE PATIENTS

Speciality : Medical Imaging Code : 62.72.01.66

SUMMARY OF THE THESIS

HÀ NỘI - 2019

MEDICAL AND PHARMACEUTICAL SCIENCES

Name of supervisor:

1 MD, PhD, Ass Prof Lam Khanh

2 MD, Ass Prof Vu Long

Reviewer 1: ………

Reviewer 2: ………

Reviewer 3: ………

The thesis will be upholded by hospital council at:

h date month year 2018

Can find out more about this thesis in:

1 National Library

2 Library of 108 Institute of clinical Medical and Pharmaceutical sciences

POSITION OF THE PROBLEM

Importance of the problem:

Cerebral infarction is a severe diease which is the 3rd most common cause of mortality in Viet Nam after cancer and myocardial infarction Ischemic stroke makes some serious sequelae, 50% alive patients got paralytic symptoms and depended on the helping of the community

Motor paralysis is a symptom highly related to the damage of the pyramidal tract In the past, the diagnosis of the pyramidal injury mostly depended on the Babinski sign (+) The medical imaging of the pyramid was very difficult, because it had the same density and signal with the white matter in CT and MRI imagings

The invention of DTI can display the pathway of nervers in the brain and applying this technique can evaluate the damage of the tract, study the relationship between the pyramidal damage with patient’s motor function recovery which help doctors to make a right prognosis, have an effective treatment stratery and reduce patient’s sequela Therefor, we performed this research: “Estimating pyramidal tract lesions and some Diffusion Tensor Imaging indexs related to motor function in ischemic stroke patients” in 108 Institute

of Clinical Medical and Pharmaceutical Sciences, where had a specialist stroke center and a MRI 3.0 Tesla with DTI sequence

Aim of the thesis

1 Describe the imaging characteristics of the neural tract lesions

in DTI inischemic stroke patients compared to normal people

2 Estimate the relation between some DTI indexs to motor function in ischemic stroke patients

Contribution of the thesis: This is the first research in Viet Nam

about the damage of pyramidal tract in MRI

Contribution in radiology: Develop a new technique in radiology Contribution in treatment: Help to prognose the chance of

motor recovery to make an effective treatment strategy

Presentation of the thesis

The thesis comprises 116 pages, dealing with 2 pages for Position

of the Problem, 30 pages for the Overview, 17 pages for the Subjects and Research Method, 32 pages for the Study Results, 28 pages for the Discussion, 2 pages for the Conclusions There are 45 tables, 18 charts, 28 images of the study design There are 114 references, including 13Vietnamese documents and 101 English documents

Chapter 1: OVERVIEW

1.1 Anatomy

The pyramidal tract is the most important motor pathway in the human brain The pyramidal tract includes both the motor cortex and the motor pathways

1.1.1 The motor cortex

Classically the motor cortex is an area of the frontal lobe located

in the anterior to the central sulcus It contains the primary motor cortex, the premotor cortex, the supplementary motor area

1.1.1.1 The primary motor cortex

The primary motor cortex is located between the precentral sulcus and central sulcus include central gyrus and the paracentral lobule Anatomically, the precentral gyrus can be divided into four

segments: the inferior segment, the middle segment, the superior segment, the paracentral segment

In function, each the segment of the precentral gyrusis a functionl

unit control a partof the body The inferior segment: functional unit

of the face; the middle segment: functional unit of the hand and arm; the superior segmentfunctional unit of the trunk; the paracentral segment: functional unit of the leg

1.1.1.2 The premotor cortex: The premotor cortex is in front of the

primary motor cortex, patially locate in the mesial aspect of

hemisphere anterior to the paracentral lobule

1.1.1.3 The supplementary motor area

The supplementary motor area (SMA) is located in the mesial aspect of the first frontal gyrus, anterior to the primary motor cortex

of lower extremity and above the cingulate sulcus and behind the

premotor cortex The SMA is linked with the contralateral SMA through the commissural fibers of the corpus callosum

1.1.2 Motor pathways

Motor pathways or the pyramidal pathwaysinclude two components: the pyramidal tract or corticospinal tract and the corticonuclear fibers In function, the pyramidal tract controls muscle

of the trunk, the corticonuclear fibers control muscles of the head, face and neck

The pyramidal tract

The origins and pathways of the pyramidal tract are fully decribed

in the anatomy books, we would not repeat it In general, the pyramidal tract can be divided into two parts:Upper part (hemisphere part) shaped like a fan and lower part (from cerebral stem downwards) is cylinder in shape At present, with the DTI we can see the image of pyramidal tract from the cerebral cortex to the upper part of the medulla oblongata.The pyramidal tract is composed of approximately 1 million axons of motor neuron

Each neuron consists of a cell body, one or more dendrites and an axon The axon is the primary structure part of the tract Axons with myelin sheath are called myelinated appear white, masses of such axons form the fiber bundle CNS axons are myelinate by oligo-dendrocytes, which do not provide a neurilemma Consequently, damaged CNS axon (the pyramidal tract) usually do not regenerate to result Waller degeneration

1.2 Pathology

1.2.1 Cerebral infarction

Acute stage: The necrosis process is formed, local edema of the brain, initiation is intracellular cytotoxic edemathen there were vasogenic edema and extracellularedema

Subacute stage: In this stage, the process of repair and absorption

of necrotic tissue, it takes place from the periphery towards the center of encephalomalacic area The result of this process is the formation of cyst with surrouding glial scars

Chronic stage: The appearance of the fluid-filled cavity lined by

astrocystes and glial scars, the sulci and ventricle is dilated, the gyri

is shrinked

Cerebral infarction in areas where the pyramid tract passes leads

to damage in each segment passing through This process takes place

in several stages, the last and most severe consequence is Waller degenerationin the far part of axon Neurotransmitter ability of axon

is lost

1.2.2 Damaged pyramid tract

The injury process will go through 4 stages

Stage 1: Manifested by physical interruption of the myelin sheath

and axon

Stage 2: Characterized by the destruction of the myelin sheath Stage 3: The myelin sheath almost disappeared, the glial tissue replaced the myelin sheath and axon degeneration

Stage 4: Characterized by cerebral volume lost and atropic the

white matter bundle (Waller degeneration)

Morphologically, it can only detect an axon degeneration at stage

4 Early manifestations of degeneration can only be detected by the change of FA and ADC indexes on DTI

1.3 Clinical diagnosis

Patient clinical nerve symptoms help doctors to direct the diagnosis Besides, evaluating the area of lesion, clinicians need to measure the level of losing motion though patient muscle power and the recovery by mRankin scales

-Evaluate clinical muscle power by MRC scales 1976

Display from 0-5 0 point: completely paralytic 5 points: normal power

- Evaluate the patient recovery by mRankin scales

Prognosis by Rosso (2011): good recovery if mRankin ≤ 2, bad if

6 > mRankin > 3

Chapter 2: SUBJECTS AND RESEARCH METHODS

2.1 Subjects

2.1.1 Places and time

The thesis was performed in the 108 Institute of Clinical Medical and Pharmaceutical Sciences from 2/1011 to 9/2016

2.1.2 Subjects

* Selection criteria of patients

- Paralytic patients diagnosed as brain infarct by MRI 3.0 Tesla in the 108 Institute of Clinical Medical and Pharmaceutical Sciences

- Patients had one infarct lesion located in pyramidal tract in MRI

- Patients was treated and had full records in the 108 Institute of Clinical Medical and Pharmaceutical Sciences

- Non-resident patients were recovered motion function with the stardard process over 1 year

* Criteria of Comparation

- Adults with every genders, none paralytic, none clinical symptoms

- Non-abnormal imagings in MRI

* Exclusion criteria

- Patients is not available with selection criterias

- Patiens with relapsed infart in clinical or CT scans

2.1.3 The sample size

It is calculated by this formula:

2

p q n

2.2.2 Means of research

- MRI Achieva 3.0 Tesla Phillips with 16 channel coils and DTI sequences

- Software: Extended MR Workspace

2.2.3 The protocol of MRI examination

- Perform MRI scout viewthrough the head

- Examination the brain: take the axial slides from the base to the vertex along to the OM linewith these sequences T1W, T2W, FLAIR, DWI

- Examination the pyramidal tract with DTI sequences 32 SENSE (TR: 10172 ms, TE: 93 ms) with EPI technique,the number of diffuse direction: 32; b: 1000s/mm2; matrix: 128 x 128, FOV: 230 x

230 mm; slide thickness 2 mm, voxel size: 1,8 x 1,8 x 2 mm

- Tranfer data to the workstation

2.2.4 Protocol of analyzing data and reconstruction imagings

- Build FA 2D color map

- Reconstruction 3D of the pyramidal tract from FA color map

2.3 The criteria used in study

2.3.1 General characteristics

- Comparation group:

- Infarction group

2.3.2 DTI of pyramid tract in the comparation group

- Departure of the tract, measurement of the tract in 3D

- FA, ADC values of total pyramidal tract FA, ADC values of each tract: corona radiate, internal capsule, basal ganglia, thalamus, pons

Hình 2.1 Illutration of brain shows ROIs of the CST for FA,

ADC measurements

Pons infacrt; a: top, b: center, c: bottom Source Zhang 2015

b

Corona radiataInternal capsuleMidbrain

Medulla oblongataPons infarct

a

c

2.3.3 DT imagings in infarct patients

- Imagings of infarction area: location, median area, median

depth, FA, ADC

- Imagings 2D, 3D of the pyramid tract on MRI

- The degree of the damaged of the pyramid tract, relation between tract lesions and the level of paralytic

- Relation between the characteristics of diffusion tensor indexs and the recovery after 1 year

2.4 Collecting, handlingand analysis data

2.4.1 Collecting techniques

2.4.2 Tools to collect the information

2.4.3 Handling and analysis data

Data is analysed by biomedical statistics method Analyse data by software SPSS16.0, Epi 3.5.4, Epicalc 2000.Value p < 0,05 is statistical significance

Chapter 3: RESULTS 3.1 Clinical characteristics

3.1.2.1 Time admission and time of treatment

The medium time admission since having the first symptom The hyperacute is 5,1 ± 2,1 hours The acute is 17,2 ± 6,4 hours The subacute is 83,5 ± 41,4 hours The chronic is 384 ± 145,9 hours The medium time of treatment is 17 ± 5,9 days

3.1.2.2 The recovery after 1 year

Table 3.3 mRankin scores after 1 year

3.2 Imagings characteristics in DTI

3.2.1 Pyramid tract DTI in comparation group

3.2.1.1 The size of the tract

Table 3.5 The size of the tract in the both sides

Side

Length (mm) 129,1 ± 11,4 127,8 ± 10,3 0,54 Number of fibres 498,9 ± 67,9 496,5 ± 35,8 0,82

3.2.1.2 DTI indexs of the tract

Table 3.6 FA and ADC in the whole pyramidal tract

3.2.2 Imagings of the infarct area in MRI

3.2.2.1 Distribution of the artery supplement

Table 3.7 The artery supplement

patients (n) (%)

3.2.2.2 Location of the infacrt

Table 3.8 Location of the infacrt

Location of the infacrt Number of

3.2.2.3 Medium area of the infacrt

Table 3.9-10 Medium area and depth of the infacrt

area (mm 2 )

Medium depth (mm)

Infarction

Corona radiata 384,4±319,5 15,6±8,1 Internal capsule 368,9±257,8 25,5±14,5 Basal ganglia 124±100,2 18,2±4,4

3.2.2.4 Chracteristics of DTI indexs

Table 3.11 Compare the FA and ADC values in the infarction and

the opposite side in the hyperacute and acute stages

(n=29)

Opposite side (n=29)

p

Table 3.12 Compare the FA and ADC values in the infarction and

the opposite side in the subacute stages

=33)

Opposite side (n=33)

Area supplied by MCA 0,246±0,156 0,485±0,231 0,00

3.2.3 Imagings of the tract lesions in DTI

3.2.3.1 Number of the tract lesions

Table 3.14 Number of the tract lesions

Pyramidal tract Number of

patients (n) Percentage (%)

3.2.3.2 Relation between the location of tract and the infarction

Table 3.15 Relation between the location of tract and the

infarction

Involvement

Location

No (n)

Partial (n)

Total (n)

Total (n)

Table 3.17 Compare the FA and ADC values in the infarction and

the opposite side

Pyramid tract

The infarction (n=65)

The opposite side (n=65) p

Comparation group (n=52)

Comparation group (n=52)

p

FA 0,476±0,082 0,512±0,071 0,03

ADC 0,827±0,127 0,832±0,101 0,83 Voxel 487,6±282,4 834,1 ± 82,2 0,00

Length 110,6±25,8 127,8 ± 10,3 0,00

Number of fibres 99,6±98,5 496,5 ± 35,8 0,00

3.2.3.3 Damaged in infarction pyramidal tract segments in the hyperacute stage

Table 3.20-21 Compare FA, ADC values between infarction pyramidal tract segments and the opposite side

Values Location Infarction

(n=9)

The opposite side (n=9)

p

FA

Center 0,525±0,210 0,694±0,104 0,07Top 0,438±0,181 0,512±0,150 0,39Bottom 0,478±0,152 0,648±0,210 0,08

p

FA

Center 0,488±0,204 0,608±0,176 0,04

Top 0,544±0,153 0,509±0,136 0,43Bottom 0,556±0,162 0,617±0,172 0,24

ADC

Center 0,613±0,202 0,747±0,114 0,01

Top 0,673±0,172 0,785±0,096 0,01

Bottom 0,698±0,176 0,815±0,175 0,03

3.2.3.5 Damaged in infacrtion pyramidal tract segments in the subacute stage

Table 3.24-25.Compare FA, ADC values between infarction pyramidal tract segments and the opposite side

Values Location Infarction

(n=33)

The opposite side (n=33)

p

FA

Center 0,507±0,236 0,680±0,132 0,00

Top 0,445±0,194 0,585±0,118 0,00 Bottom 0,601±0,205 0,667±0,176 0,16

ADC

Center 0,620±0,227 0,725±0,212 0,05

Top 0,724±0,214 0,725±0,137 0,98Bottom 0,693±0,211 0,736±0,179 0,37

In this research, there were 3 patients in the chronic stage The number of patients aren’t enough to perform comparation

3.2.4 Relation between the tract DTI indexs and the patient’s motor function after 1 year

Table 3.26 The degree of the tract lesion followingNelles (2008)

Statement Location

Intact (n)

Partial disruption (n)

Complete disruption (n)