Studying anatomy of cerebral arteries images on multislice computed tomography 256

% P1 T 250 2,37±0,49 0,6-3,7 2,3-2,4 P 253 2,37±0,48 0,5-3,6 2,3-2,4 P2 T 261 2,42±0,35 1,5-3,2 2,4-2,5 P 261 2,38±0,38 1,0-3,3 2,3-2,4 P3 T 255 1,74±0,41 0,7-2,9 1,7-1,8 P 260 1,67±0,4 0,5-2,7 1,6-1,7 VA T 261 3,62±0,88 1,2-6,7 3,5-3,7 P 260 3,18±0,85 0,8-6,0 3,1-3,3 BA 261 3,7±0,6 2,0-5,9 3,6-3,8 Posterior inferior cerebral Artery T 209 1,55±0,43 0,5-3,1 1,5-1,6 P 197 1,52±0,39 0,6-2,8 1,5-1,6 Anterior inferior cerebral Artery T 178 1,11±0,35 0,5-2,4 1,1-1,2 P 183 1,07±0,32 0,5-1,9 1,0-1,1 Superior Cerebral Artery T 260 1,31±0,35 0,5-3,0 1,3-1,3 P 261 1,23±0,31 0,5-2,0 1,2-1,3 Table 3.3: Average diameter of cerebral arteries originating from BA According to Table 3.3: average diameter segment P3 was the smallest in the PCA. Average diameter of posterior inferior cerebral artery was the largest among the cerebellum regions. According to Table 3.4: P3 segment has the largest length among the segments 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 Artery Side n Average Length ± SD Min-Max 95% P1 T 252 11,92±8,60 4,6-83,0 10,9-13,1 P 255 11,28±3,49 4,3-25,3 10,8-11,7 P2 T 261 28,55±8,04 4,3-60,3 27,6-29,5 P 261 26,84±9,18 10,1-75,6 25,7-28,0 P3 T 255 39,41±12,64 6,0-77,9 37,8-41,0 P 260 39,47±13,09 7,7-79,5 37,9-41,1 VA T 261 43,81±6,88 23,5-64,9 43,0-44,6 P 260 42,89±7,04 4,0-65,3 42,0-43,8 BA 261 28,85±4,73 18,1-54,0 28,3-29,4 3.2. Measurements of angles 3.2.1. Correlation between angles and age Table 3.5: Correlation between angle index and age Angles Side Age group p ≤ 60 Age > 60 Age ± SD ± SD A2-Callosomargin Left 117,15 ± 24,44 112,56 ± 33,46 >0,05 Right 122,17 ± 28,60 117,47 ± 31,90 >0,05 ICA-ECA Left 40,30 ± 27,16 48,77 ± 24,14 <0,05 Right 31,37 ± 18,75 41,39 ± 22,15 <0,05 Posterior Genu Left 85,74 ± 38,40 83,02 ± 38,42 >0,05 Right 91,01 ± 42,00 80,35 ± 41,64 >0,05 Anterior Genu Left 45,27 ± 20,50 49,72 ± 22,21 >0,05 Right 42,88 ± 19,60 45,13 ± 24,73 >0,05 BA-PCA Left 128,50 ± 14,02 125,41 ± 20,13 >0,05 Right 126,31 ± 14,20 116,60 ± 18,58 <0,05 VA left-right 49,03 ± 20,65 46,20 ± 21,59 >0,05 According to Table 3.5: angle of ICA-ECA (Inner-External carotid artery) was related to age; specifically, the group under 60 had the smaller angle value than the group over 60 old old. In other angles, the values did not 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 Arteries side n Hypoplasia (%) Aplasia (%) A1 Left 261 0 2,3 Right 261 2,3 1,15 A2 Left 261 0 1,15 Right 261 0 0 A3 Left 261 1,5 1,15 Right 261 3,0 0,77 Callosomargin Left 261 6,9 1,15 Right 261 5 0,4 Heubner Left 261 0 97,3 Right 261 0 96,9 Striate Left 261 0 1,5 Right 261 0 1,15 M1 Left 261 0 0 Right 261 0 0 M2 upper Left 261 0 0 Right 261 0 0 M2 lower Left 261 0 0 Right 261 0 0 Segment ICA of neck Left 261 0 0 Right 261 0 0 Segment ICA epidural intracranial Left 261 0 0 Right 261 0 0 Ophthalmica artery Left 261 0 0 Right 261 0 0 According to Table 3.6: the largest rate of variation was found in Heubner’s artery 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 lowest variation rate was 0% found in BA, VA on the left. Table 3.7: Variations in the dimensions cerebral arteries originating from BA Artery n Hypoplasia (N) Aplasia (N) Khác P1 L 261 4 8 0 P1 R 261 6 5 1 P2 L 261 0 0 0 P2 R 261 0 0 0 P3 L 261 6 6 0 P3 R 261 11 1 0 VA L 261 0 0 0 VA R 261 2 1 0 BA 261 0 0 0 Posterior inferior cerebral Artery L 261 16 52 0 Anterior inferior cerebral Artery L 261 71 68 0 Superior cerebral Artery L 261 34 0 0 Posterior inferior cerebral Artery R 261 12 63 0 Anterior inferior cerebral Artery R 261 80 68 0 Superior cerebral Artery R 261 53 0 0 + Communicating Artery According to Figure 3.3: the total AComA variation of the group above 60 old was 20.57%, while the group under 60 old had only 15.12%. Among the two age groups, the age group above 60 has the highest rate of variation with 24.57% at PComA R aplasia; the lowest was 2.86% found in AComA hypoplasia; in the group below 60 old, the highest rate of variation was 18.6% in PComA R hypoplasia; the lowest was 3.49% in AComA. 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 the morphological 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. With ICA, 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 % ACA 1 1,16 10 5,7 3 3,49 3 1,7 1 1,16 8 4,57 MCA 0 0 0 0 1 1,16 0 0 1 1,16 0 0 AComA 0 0 2 1,14 3 3,48 4 2,28 0 0 1 0,57 PComA 1 1,16 1 0,57 0 0 0 0 1 1,16 0 0 ICA 0 0 0 0 0 0 0 0 0 0 2 1,14 Total 2 2,32 13 7,43 7 8,14 7 4 3 3,49 11 6,3 + Cerebral arteries originating from BA Table 3.8: Morphological variation of cerebral arteries originating from BA by age Variation Artery Duplication Fenestration Different Variation ≤60 N % >60 N % ≤60 N % >60 N % ≤60 N % >60 N % VA 0 0 0 0 1 1,16 2 1,14 1 1,16 0 0 BA 0 0 1 0,57 4 4,65 2 1,14 0 0 1 0,57 PCA 0 0 0 0 0 0 0 0 2 2,32 10 5,7 Total 0 0 1 0,57 5 5,8 4 2,28 3 3,48 10 5,7 According to Table 3.8: group>60 old, 65% (15/23) of morphological variations. PCA has the most variations, 66.7% variants of the whole group>60 old. Group ≤60 old with the most fenestration-forming variant accounts for 21.7% (5/23) of the variation. 3.3.3. Variant of cerebral artery polygon Figure 3.4: Percentage of cerebral artery polygon variation by gender According to the Figure 3.4: 32,2% (84/261) subjects had normal cerebral artery polygons. 67.8% (177/261) was variation; including 90 cases of simple variation, 87 cases of complex variation. Male having normal cerebral artery polygons accounted for 47.12% (41/87) among patients having normal cerebral artery polygons and 29.3% (41/140) of all men; these percentages among females were 52.88% (43/87) and 35.5%, respectively. The number of men with a variation was 70.7% (99/140), the number of women with a variation was 64.5% (78/121), the difference was statistically significant (p <0.05). Figure 3.5: Classification of many cerebral artery polygon variations According to Figure 3.5: with complex variation, the size - size variation (91.95%) was the most common. The least frequent variation was morphological - size at 1.15%. CHAPTER 4: DISCUSSION 4.1. Percentage of cerebral arteries image display 4.1.1. Cerebral arteries originating from ICA According to Figure 3.1: the visualization rate of ACA was 99.36%; segments A1, A2, A3, as well as right and left sides, were capable of displaying full image differently. A2P segment had the highest image display rate of 100%. According to Pham Thu Ha when studying the cerebral artery polygon of the subjects having cerebral aneurysms, there were 4.12% (211/218) of A1 segment without images (aplasia); 100% (218/218) of A2 segment appeared, A3 was not mentioned in the study. Thus, the visualization rate of ACA in our study was similar to that of previous study, however, for A3 which is the furthest segment of ACA, the image displayed ratio was 95%, showing the superiority of MSCT 256 when evaluating the artery segment away from the center. For Callosomarginal artery, according to Cavalcanti when studying callosomarginal artery by autopsy and images of 60 brains, the likelihood of appearance of callosomarginal artery was 93.3% of which 55.2% come from segment A3. In our study, callosomarginal artery had good image. We did not evaluate the origin of this artery. With AComA, there was the highest rate of variation in the anterior half of the brain artery. According to Pham Thu Ha, variation rate was 11% when studying with MSCT 128 and 10.09% when studying by Digital Subtraction Angiography; however, there was a confounding factor in the study of AComA by angiogram with injection of contrast material. Since AComA is the ACA connecting on both sides, in case that flow pressure in the blood vessels of both sides was equal, contrast agent will be difficult to circulate to AComA, affecting the percentage of image to film display. Surgical techniques will not encounter this problem. In Heubner artery, percentage of image displayed was very low at about 2.9%. According to Impiombato when using digitized angiography to study of 100 subjects from 5-90 old, this rate was 12%. Meanwhile, Matsuda studying in 357 brains and found that 98.74% appeared Heubner artery. In our opinion, Heubner artery had about 0.8mm diameter, original source usually variants which can be from segment A1 (7.5%), A2 (16.3%) or the connection between A1 and A2 (76, 2%), making it difficult to identify the artery and to display images on film. If artery is small, not far from the root cause, the method of autopsy may be advantageous in finding the blood vessel. The percentage of image displayed for striate artery was 98.65%, no image displayed was 1.35%. We could not find data in previous studies for comparison. The percentage of image displayed in MCA, segment ICA of neck, segment ICA epidural intracranial, and Ophthalmica artery were 100% on MSCT 256. In our opinion, because these arteries are large branches with wide blood supply area, high flow rate, good circulation, these arteries could be fully displayed. For PComA, it had the highest variation rate among the studied arteries, average percentage of no image was 21.65%; poor image was 1.92%; according to Pham Thu Ha, percentage of no image was 23.85% (52/218) when studying with MSCT and 10.55% when studying using Digital Subtraction Angiography; Anubha Saha had 38.2% when performing autopsy, no PComA was found. Thus, the study of PComA anatomy by Digital Subtraction Angiography, which clears the background of image, had better ability to display the image compared to other methods. 4.1.2. Cerebral artery image display originating from the BA According to Figure 3.2: the average percentage of PCA was 98.7% in the P1 segments; P2 and P3 had different display ratio. According to Cihad Hamidi, percentage display of PCA was 100% when assessed by MSCT 64. In our study, percentage display of P2 was the highest among the 3 segments because P2 was supplied with blood from two sources: from BA through P1 and ICA via PComA.  The percentage of VA was 99.8% (521/522), in the study we encountered 01 case of VA aplasia on the right. When studying common anatomy and VA-BA system variants MSCT 65 and magnetic resonance imaging, Akgun did not report this variant. The percentage of BA was 100% because its a large coronary artery, has an important role in blood supply to the brain so the drug circulates well and has a display well. The studies of Dimmick, Akgun, and Harish did not meet the aplasia variant. Cerebellar arteries had varied percentage of images displayed from 73.9% to 100%. In particular, cerebellum on the brain was most likely to have image because it is the largest coronary artery from BA and has good ability to circulate drugs. According to Akgun when studying cerebellum arteries by CT 64 and magnetic resonance imaging, percentage of images displayed ranged from 75.6%-82.2%, which was not much different from our study. 4.2. Size of cerebral arteries 4.2.1. Size of cerebral arteries originating from ICA + Average diameter Aggarwal, when studying length of ACA by magnetic resonance imaging, divided ACA into 3 segments as the criteria we applied, but in this study, author has not been able to evaluate dimensions of A2 and A3. In 2012, Canaz studied 60 hemispheres on fresh corpses and indicated sizes of segments A1 and A2, but could not evaluate A3. Differences in results of the aforementioned studies were due to the application of different research equipment: magnetic resonance imaging, MSCT, vascular autopsy; subjects studied were different: artery of living human, formol corpses and fresh corpses. With MCA, authors all agreed on the division of main segments: M1, M2 above, M2 below. According to Gokmen, percentage of having an intermediate trunk is 61%. Gokmen is one of the few authors who have assessed the upper and lower diameter of MCA that research team found out. Our measurement results are different from the other authors on the average diameter of MCA which may be due to ethnicity and sample size. The left and right border of callosomargin artery had diameter in the range of 1.4-1.5; maximum value was 8.1mm on the left; minimum 0.5mm on the right. Canaz showed left border of callosomargin artery1.27 ± 0.36mm; right of callosomargin artery 1.23 ± 0.15mm maximum of 2.8mm on the left, minimum of 0.83mm on the right. In terms of mean values, there was no difference between two studies. With PComA, research results of the authors are different, in our opinion this difference is due to that study subjects had different races, Alfredo studied on Europeans, Pham Thu Ha and we studied on Southeast Asian people. Moreover, research equipments were also different: Alfredo uses anatomic method, Pham Thu Ha and we use MSCT. With PComA, research results of the authors are different, in our opinion this difference is due to the study subjects are different races, Alfredo studies on Europeans, Pham Thu Ha and our study rescued in southeast asia. At the same time, research facilities are also different, Alfredo uses anatomic method, Pham Thu Ha and we use MSCT. With ICA, we evaluate 2 sections: the left neck segment had average diameter at 4.63±0.55mm; and right segment had average diameter at 4.63 ± 0.60mm. Segment on the left of cranial epidural had average diameter at 5,10±0,84mm; Segment on the right of cranial epidural had average diameter at 4.98±0.79mm. According to Masatou kawashima, results of ICA autopsy showed that average diameter artery of neck segment was 8.57±1.34mm; petrous bone segment 5.42±0.68mm; sella turcica segment 3.95±0.56mm. Differences may be due to the application of different research equipment. + Average length With ACA: Huseyin applied autopsy on 30 fresh European corpses, Sandhya Gunnal applied the autopsy of 112 formolled corpses of people in South Asia, we applied MSCT 256 to study 261 people in South East Asia. When comparing research equipment, it is possible to see that length of ACA segments when measuring on the diagnostic imaging device (MRI or MSCT) was different from measurement on body. In terms of corpses, results also differed between freshly frozen corpses and formolled corpses. Research’s team did not report evaluated the A3 segment which could be due to the fact that this section was far from the origin and it was complicated and difficult to assess. With MCA: Brzegowy and Vladimir Rohan divided same division M1, upper body (upper M2), lower body (lower M2) as us, but the authors only evaluate M1 index, while other segments have not been research. Our study has supplemented average length of upper and lower M2 segments which was previously unavailable. With AComA, it was studied by many authors such as XuTao, ​​Huseyin Canaz, Ayse Karatas, and Pham Thu Ha by using a various of means such as MSCT 64, 128, 256, or vascular autopsy, on many objects such as fresh corpses, formolled corpses, people living without cerebrovascular pathology, people with cerebrovascular disease, in different races. With all of the above factors, research results on AComA are very different. With ICA, neck segment has a larger average length than the intracranial segment. According to Vijaywargiya, average length of left and right petrous segments were at 31.76±6.46mm and 30,33±6,65mm, respectively. Average length of the left and right sinus segments were at 37.97±8.90 and 37.91±8.86mm, respectively. We divided ICA into 2 segments, intracranial and cerebral segments. Pham Thu Ha, when studying subjects with cerebral artery variation, pathologies often occured in cerebral artery polygon. Therefore, divided ICA does not bring much clinical significance, and identifying between anatomic landmarks on the film is difficult. Therefore, we propose to combine two segments mentioned above into a segment so-called epidural intracranial ICA. 4.2.2. Size of cerebral arteries originating from BA + Average diameter Vitosevic and Pham Thu Ha studied nearly all the arteries, main arterial branches supplying blood to brain originating from BA such as VA, BA, segment P1, P2, P3 of PCA. Only segment P3 have not been mentioned in the previous studies but have been supplemented by us. Anatomically, all studies showed consistent results when the main blood vessel would have large average diameter, the secondary blood vessel would have smaller average diameter in order of BA> VA; BA> PCA; P2> P3. For cerebellum arteries, PCA had the largest average diameter. This result is also published by Akgun, so the upper cerebellar arteries did not have the largest average diameter as previously known. + Average length PCA is an artery that has been studied by many authors and published the most different results, in our opinion, due to the inconsistent view of dividing segments of PCA, especially P2, P3, P4. According to the international nomenclature, PCA is divided into four sections: precedent communicating segment or the P1 segment; posterior communicating segment or P2 segment goes from the connecting node with PComA to the place separating external occipital artery (lateral) and internal occipital artery (central occipital); segment P3 is external occipital artery (lateral), a large lateral branch of PCA that supplies blood to underside of temporal lobe; segment P4 or internal occipital artery (central) is terminal end of PCA. We apply this division to research, so results of our length measurement are often larger than other authors. For BA: according to Filip Vitosevic, average length was 31.98±4.93 when studying 150 European subjects with MSCT 64. Result was lower than our study, possibly due to racial factor, both studies have applied imaging facilities with software to support the study. 4.3. Angles index Table 3.5 provides sufficient parameters of important constituent angles of cerebral arteries in group> 60 old old, value of angle ICA-ECA is greater than the group ≤60 old old, difference is statistically significant (p <0,05). Thus, through this study we can confirm that values of angle are not related to age. Our conclusion agrees with Feng Fan. 4.4. Anatomy of variant cerebral arteries 4.4.1. Size variation + Cerebral arteries originating from ICA According to Table 3.6: size variation mainly occurs in ACA: segments A1, A2, A3 and artery detached from ACA as Callosomargin, or Heubner arteries. Specifically, size variation of ACA: 3.4% hypoplasia; 3.26% aplasia. Among ACA segments, A3 segment has the highest frequency variation size of 3.21%. With Heubner artery, study noted that percentage of aplasia up to 97.1% was very high. Other arteries in the study, such as MCA, ICA segment of neck, and ICA segment of epidural intracranial, were not recorded in size variation. According to Michelle, rates of hypoplasia and aplasia in segment A1 were 5.3% and 5.65% respectively; segment A2 were 4.25% and 0.35%; segment A3 the author did not evaluate. In our study, rate of hypoplasia and aplasia of segment A1 are lower than Michelle's result, one of the reasons we think of is that the resolution of MSCT 256 is higher than MSCT 64. + Cerebral arteries originating from BA According to Table 3.7: size variation appears near whole (except BA and left VA) artery derived from BA. In particular, cerebellar arteries have the largest variation 33.01% (517/1566); BA has the smallest variation 0%; variation percentage of segments of PCA is 3% (48/1566); variation rate of VA is 0.57% (3/522). With PCA, P3 and P1 segments have the largest variation 4.6% (24/522), P2 segment has the lowest variation rate among the 3 segments with 0%. According to the fact that artery segment as far away from the origin is easier to be variant, but P2 segment has a smaller size than P1 segment; in our opinion, because P2 segment receives more blood from the ICA system through PComA, hypoplasia variant was low, resulting in the percentage of size variation was generally lower than P1 (not supplied by the ICA system). According to our research, cereberal arteries are often less studied than main arteries such as PCA, BA, VA. Sangma Sarah, when evaluated by using MSCT 64, found: cerebellar aplasia below one side 16%; aplasia on both sides 3%; right of 10%; 6% on left. The other arteries we have not found documents to mention. + Communicating Artery According to Figure 3.3: total AComA variant of group> 60 old was 20.57% while that of ≤60 old group was only 15.12%. Similarly, total variants of PComA L was 43.43% and 26.75%; total variants of PComA R was 35.43% and 31.39%, respectively. Among two age groups, the group> 60 old with the highest variation rate was 24.57% in PComA R aplasia; the lowest was 2.86% found in AComA hypoplasia; group≤60 old has the highest rate of variation is 18.6% in PComA L hypoplasia; the lowest is 3.49% in AComA. Thus, the higher of age, more anatomical variants in communicating artery of which the most common are variants in PComA. Now, no similar studies have been published, we have added correlation between age and percentage of variants of coronary artery in the anatomical knowledge. 4.4.2. Morphological variation of cerebral arteries + Cerebral arteries originating from ICA According to Table 3.7: group>60 old, 72% (31/43) morphological changes by age group, group≤60 old 28%. Among group> 60 old, percentage of ACA variation was the highest with 67.7% (21/31); at the same time MCA has no change in this age group. For group≤60 old, morphological changes in ACA are the most common in studied arteries 50% (5/10); at the same time, ICA has no change in this age group. Considering each artery being studied, ACA is 60.4% (26/43) of total morphological variations of all studied arteries; and group> 60 old, 80.77% (21/26) ACA variants. Thus, the higher age, the greater the variation in ACA. In terms of variation, two artery bodies in group>60 old are the most common in ACA changes with 38.46% (10/26); however, this is rare in age group<60 with only 3.84% (1/26) of all ACA variants. With MCA, rate of variation was very low, 4.65% (2/43) of total morphological changes of studied arteries. However, this variation is only found in age group ≤ 60 (2/2), so in our study, the age group> 60 has no variation. In terms of each type of variation, we did not encounter a bilateral MCA arterial variant at all ages in our study, fenestration - form angiogenic variant accounting for 50% (1/2) of total MCA morphological variant and only seen in the age group ≤ 60 old. With AComA, variation percentage 23.25% (10/43) of the total variation, of which the age group>60 old 70% (7/10). Thus, the higher the age of AComA was, the higher morphological variation was. Considering each variation, vascular fenestration of group> 60 old was the most common among AComA variants, 40% (4/10). We did not encounter duplication variant in group <60 old. With PComA, variation percentage 6.98% (3/43) of total morphological variations, of which ≤ 60 old group 66.67% (2/3). Thus, patients with the younger age were more likely to encounter PComA morphological variation. In terms of each variation, study did not find a vascular fenestration variant of PComA at any age, percentage duplication accounted for 66.67% of PComA total variation and was equal in two age groups. With ICA, variation percentage 4.65% (2/43) of total variation, and only occurs in group>