Poor image display: the artery is displayed on the film; however, there is an interruption along the length of that artery from the beginning to theend and the corresponding length or di
Trang 1The brain has an important role in coordinating all activities of thehuman body Brain only performs its functions when having normalanatomical structure and adequate blood supply Inner carotid artery (ICA)and Vertebral artery (VA) are the two main sources supply blood to thebrain Because of its important role in maintaining brain activity, cerebralarteries are the target of many specialties in medicine There are manymethods of anatomical research to cerebral arteries, one of which multislicecomputed tomography (MSCT) angiography, was known for manyadvantages: rapid performance, less invasive, with the ability to renderartery in three dimensions, clear images, which can illustrate small vesselsfar away from the origin, and a large number of films that allows tocompute the rare anatomical variants, as well as easy to store these films for
1 Evaluating the percentage of cerebral artery image displayed on multislicecomputed tomography 256
2 Describe the common types and anatomical variants of cerebral arteries
NEW CONTRIBUTIONS OF THE THESIS
1 Measuring the percentage of cerebral artery image displayed byMSCT 256 for the first time
2 Figuring out the characteristics of Vietnamese cerebral vascularanatomy on length, diameter, branch, angle, morphological variation, andsize variation Suffering analyze the correlation between vascular anatomyand gender and age Full analysis about correlation between vascularanatomy and gender and age
3 Announced 58 types of cerebral artery polygon variations in Vietnam,including many variants that have not been mentioned in previous studies
THESIS OUTLINE
The thesis consists of 129 pages (excluding references and appendices),with the following main sections: Introduction 2 pages; Chapter 1:Literature review 28 pages; Chapter 2: Subjects and Methods 17 pages;Chapter 3: Results 35 pages; Chapter 4: Discussion 44 pages; Conclusion: 2pages; Recommendations: 1 page The thesis has 28 tables, 8 figures,1diagram and 85 images References included 120 documents Five articlesthat are directly related to the thesis have been published
Trang 2CHAPTER 1: ACKNOWLEDGEMENT 1.1 Multislice Computed tomography angiography
1.1.1 The basic principle of MSCT
MSCT: the scanner is designed with a round that allows X-ray tubes andreceivers to rotate freely 360 degrees, allowing image data to becontinuously and quickly captured while the machine is moving The digitalimage data set of MSCT angiography is very large, transmitted to the host,processed images by specialized software
Patients undergoing MSCT are injected iodine drug of 300-400mg /ml,dose of 1-1.5ml / kg, large intravenous injection at 3-5 ml/s, total dose from60-100ml After bolus injection, aortic artery will be observed internally,and the machine automatically scans from vertebral C1 up to the top of theskull The thickness of slices is from 0.5 to 1.25mm, with 0.6mm rendering
1.1.2 Rendering techniques after capturing images
There are many methods of rendering, we choose some methods used inthe study:
+ Maximum Intensity Projection (MIP): technique can be quickly andeasily rendered on the computer of the MSCT Images can be made indifferent thicknesses This technique is based on detecting the highestdensity pixels in a given ray, which is sensitive to signals that overlap fromadjacent bone or venous structures that capture drugs
+ Curved Reformat (CR): this technique applies when evaluating theentire path of a long and zigzag blood vessel, such as carotid artery and VA
In this image editing technique, the artery is detected along its path withpixels to display the user-selected image on successive cross-sectionalimages CR images are useful for screening ICA and VA
+ Volume Rendering (VR): non-surface pixels are also included in thedata set This is an advantage, because when different thresholds are set, thelayers of blood vessels can be peeled off or made transparently, therebyshowing the underlying structures
1.1.3 The value of computed tomography angiography
According to Ayarayman (2004), compared with digitized angiographywhen evaluating blood vessels, MSCT has 81-90% sensitivity and 93%specificity Li (2009) reported that MSCT 64 had a sensitivity of 99%, a100% specificity; a positive predictive value (with lesions) was 100% and anegative predictive values (without injury) was 92.3% in diagnosingcerebral artery variants
Trang 31.1.4 Multislice Computed tomography 256
MSCT 256 is the 4th generation of computed tomography This isproduced by the General Electric company, and is approved by the US Foodand Drug (FDA) in 2014 with many advantages, such as 0.28 seconds/1snapshot time, rotation distance/1 rotation is 16cm, good image quality;radiation dose reduces by 82% compared to previous machine
According to Su-Kiat Chua (2013), when comparing MSCT 256 withMSCT 64 in coronary artery disease research, some conclusions weremade: the MSCT 256 had a shorter scan time (4.4 ± 0.6 seconds compared
to 5.0 ± 0.7 seconds, p <0.001) compared to MSCT 64 MSCT 256angiography was more accurate in diagnosis based on patient analysis(97% vs 83%, p <0.05) than MSCT 64 According to our research, noapplication of MSCT 256 in cerebral angiography has been found
1.2 Variant anatomy of cerebral artery
1.2.1 Definition
+ Size variations included 2 types
Aplasia: there is no vascular segment appearing on the rendering image.Anatomically, aplasia is considered to have no vascularity
Hypoplasia: the segment diameter is <1mm for the main artery and
<0.5mm for the Communicating artery
Some other variations of the name according to actual image:trifurcation of cerebral artery, azygos cerebral artery
1.2.2 Variant of cerebral artery polygon (Willis Circle)
The cerebral artery polygon is the connection between two carotidsystem and BA system According to classic anatomy, anterior half polygonhas two anterior cerebral arteries (ACA) connected by anteriorcommunicating artery (AComA) The posterior half polygon has twoposterior cerebral artery (PCA) connected to posterior communicatingartery (PComA)
There are two classified variations of cerebral arteries: the first way,according to anterior or posterior half polygon; the second way, according
Trang 4to simple variant (only one cerebral artery variant) or complex variant (two
or more variant) In 2011, Hoang Minh Tu announced 18 types variants ofVietnamese people without cerebrovascular disease when studying withMSCT 64 In 2018, Pham Thu Ha recorded 20 types of cerebral arteryvariants in Vietnam when studying with MSCT 128
CHAPTER 2: MATERIALS AND METHOD
2.1 Research subjects
261 cerebral artery image files of the study subjects (no cerebrovascularpathology) were taken by MSCT 256 machine at Huu Nghi Hospital'sDiagnostic Imaging Department, from July 2017 to December 2018
2.2 Research Methods
The study was conducted using a cross-sectional design, recruiting alleligible patients until reaching the necessary sample size
2.3 Research variables
Full image display: the artery is clearly displayed on the film
Poor image display: the artery is displayed on the film; however, there is
an interruption along the length of that artery (from the beginning to theend) and the corresponding length or diameter cannot be measured
No image display: there is no artery in the film taken through two ormore rendering
The length of the artery is measured along artery from the beginning tothe end
The diameter of the artery is measured at the middle of cerebral artery,
on the cross-section diagram of artery
The angle of artery branches is determined by drawing two lines: astraight line through axis of blood vessel to determine angle, and a straightline through axis of main artery that divide the artery branches Theseparation angle of branch is angle between these two lines and thedirection of blood flow
Trang 5CHAPTER 3: RESEARCH RESULTS 3.1 Percentage of image display cerebral arteries
3.1.1 Percentage of cerebral artery image display originating from ICA
Figure 3.1: Rate of cerebral artery image display is originating from ICA
According to Figure 3.1: percentage of images displayed 100% wasfound in the Middle Cerebral Artery (MCA) and ICA The percentage ofimages displayed >90% was seen in the ACA and striate arteries Thelowest rate of images displayed was seen at recurrent artery of Heubnerwith 2.9%
3.1.2 Percentage of cerebral artery image display originating from BA
According to Figure 3.2: The percentage of image displayed 100%was found in basal artery (BA) and Supper cerebral artery (SCA).The percentage of image displayed > 90% was seen in PCA, and VA
Full display Poor display
Figure 3.2: Rate of cerebral artery image display originating from BA Note: SCA: Supper cerebral artery; AICA: Anterior inferior cerebral artery;
PICA: Posterior inferior cerebral artery
Trang 63.2 The size of cerebral arteries
3.2.1 The size of cerebral arteries originating from ICA
According to Table 3.1: average diameter segment A1 of ACA was
greater than A2 and A3 The segment M1 was larger than that of the
segment M2 above and below Average diameter ICA was the largest
among the arteries
Table 3.1: Average diameter of the cerebral arteries originating from ICA
diameter ± SD Min-Max 95%CI
Trang 7Table 3.2: Average length of the cerebral arteries originating from ICA
Artery Side n Length ± SD Average Min-Max 95%CI
A1 TP 255258 17,26±3,1517,12±3,34 9,1-41,12,1-28,2 16,9-17,616,7-17,5A2 TP 258261 43,88±11,6543,79±14,12 13,8-73,58,0 - 95,2 42,4-45,342,1-45,5A3 TP 258259 54,84±16,0655,60±15,86 5,2-101,412,0-96,1 52,8-56,953,7-57,5
M1 TP 261261 19,98±6,1019,68±6,28 2,6-39,44,5-38,3 19,2-20,718,9-20,4M2 upper TP 261261 23,42±11,8922,85-13,18 2,6-77,83,5-81,7 21,2-24,522,0-24,9M2 lower TP 261261 29,11±15,3131,73-16,36 7,6-85,72,5-97,1 29,7-33,727,2-31,0PComA TP 203206 11,87±4,8714,02±9,13 1,0-48,51,4-90,4 11,2-12,512,8-15,3Segment ICA
of neck TP 261261 81,63±11,4482,55±11,22 48,7-118,156,2-120 80,2-83,081,2-83,9Segment ICA
epidural
intracranial
T 261 78,08±11,91 5,9-114,6 76,6-79,5
P 261 77.89±10,38 17,2-107,9 76,6-79,2
3.2.2 The size of cerebral arteries originating from BA
Artery Sid e n Diameter ± SD Min-Max Average KTC 95%
P1 TP 250253 2,37±0,492,37±0,48 0,6-3,70,5-3,6 2,3-2,42,3-2,4P2 TP 261261 2,42±0,352,38±0,38 1,5-3,21,0-3,3 2,4-2,52,3-2,4P3 TP 255260 1,74±0,411,67±0,4 0,7-2,90,5-2,7 1,7-1,81,6-1,7
VA TP 261260 3,62±0,883,18±0,85 1,2-6,70,8-6,0 3,5-3,73,1-3,3
Posterior inferior
cerebral Artery TP 209197 1,55±0,431,52±0,39 0,5-3,10,6-2,8 1,5-1,61,5-1,6Anterior inferior
cerebral Artery TP 178183 1,11±0,351,07±0,32 0,5-2,40,5-1,9 1,1-1,21,0-1,1Superior Cerebral
Artery TP 260261 1,31±0,351,23±0,31 0,5-3,00,5-2,0 1,3-1,31,2-1,3
Table 3.3: Average diameter of cerebral arteries originating from BA
Trang 8According to Table 3.3: average diameter segment P3 was the smallest
in the PCA Average diameter of posterior inferior cerebral artery was thelargest among the cerebellum regions
According to Table 3.4: P3 segment has the largest length among thesegments of PCA Length of VA segment in the skull was longer than the
BA segment
Table 3.4: Average length of cerebral arteries originating from BA
3.2.1 Correlation between angles and age
Table 3.5: Correlation between angle index and age
28,60
117,47 ± 31,90 >0,05
ICA-ECA
Left 40,30 ± 27,16 48,77 ± 24,14 <0,05Right 31,37 ± 18,75 41,39 ± 22,15 <0,05Posterior Genu Left 85,74 ± 38,40 83,02 ± 38,42 >0,05
Right 91,01 ± 42,00 80,35 ± 41,64 >0,05Anterior Genu Left 45,27 ± 20,50 49,72 ± 22,21 >0,05
Right 42,88 ± 19,60 45,13 ± 24,73 >0,05
14,02
125,41 ± 20,13 >0,05
Trang 9Right 126,31 ±
14,20
116,60 ± 18,58 <0,05
VA left-right 49,03 ± 20,65 46,20 ± 21,59 >0,05According to Table 3.5: angle of ICA-ECA (Inner-External carotidartery) was related to age; specifically, the group under 60 had the smallerangle value than the group over 60 old old In other angles, the values didnot differ among age groups
3.3 Anatomical variation
3.3.1 Size variation of cerebral arteries
+ Cerebral arteries originating from ICA
Table 3.6: Dimension variation of cerebral arteries originating from ICA
Trang 10According to Table 3.6: the largest rate of variation was found in Heubner’sartery at 97.1% The lowest rate was 0% for artery of ICA - MCA The arteries
on each side and each segment have different variation rates
+ Cerebral arteries originating from BA
According to Table 3.7: the most common size variation was found
in right anterior cerebellum with less than 56.7% (148/261) The lowestvariation rate was 0% found in BA, VA on the left
Table 3.7: Variations in the dimensions cerebral arteries originating from
Trang 11AComA hypoplasia; in the group below 60 old, the highest rate of variationwas 18.6% in PComA R hypoplasia; the lowest was 3.49% in AComA.
Hypoplasia > 60 Hypoplasia =<60 Aplasia > 60 Aplasia=<60
Figure 3.3: Dimension variation of communicating artery by age group 3.3.2 Morphological variation
+ Cerebral arteries originating from ICA:
According to Table 3.7: the group>60 old, 72% (31/43) of themorphological variations by age group The group> 60 old of ACA, 83.9%(26/31) of the total number of variants occurring at the age of> 60 old WithICA, there was only morphological variation in the age group> 60 old
Table 3.7: Morphological variation of cerebral arteries originating from
ICA by age group
Variation,
Age
group Artery
Duplication Fenestration Different
Variation
≤ 60 N
%
>60 N
%
≤ 60 N
%
>60 N
%
≤ 60 N
%
>60 N
Trang 12Total 2,322 7,4313 8,147 74 3,493 6,311
+ Cerebral arteries originating from BA
Table 3.8: Morphological variation of cerebral arteries originating from
BA by age
Variatio
n Artery
Duplication Fenestration Different
Variation
≤60 N
%
>60 N
%
≤60 N
%
>60 N
%
≤60 N
%
>60 N
%
0
00
11,16
21,14
11,16
00
55,8
42,28
33,48
105,7According to Table 3.8: group>60 old, 65% (15/23) ofmorphological variations PCA has the most variations, 66.7% variants ofthe whole group>60 old Group ≤60 old with the most fenestration-formingvariant accounts for 21.7% (5/23) of the variation
3.3.3 Variant of cerebral artery polygon
15.7
Female
Column1
Figure 3.4: Percentage of cerebral artery polygon variation by gender
According to the Figure 3.4: 32,2% (84/261) subjects had normalcerebral artery polygons 67.8% (177/261) was variation; including 90 cases
of simple variation, 87 cases of complex variation Male having normalcerebral artery polygons accounted for 47.12% (41/87) among patientshaving normal cerebral artery polygons and 29.3% (41/140) of all men;these percentages among females were 52.88% (43/87) and 35.5%,