Anatomical Study Of The Relationship Between Each Segment Of Anterior Cerebral Artery And Anterior Communicating Aneurysm

Objective:In this study,we used human specimen anatomy,CT angiography（CTA）and digital subtraction angiography（DSA）techniques to measure the basic anatomical data of segments A1-A3 of the anterior cerebral artery.And the differences between different measurement methods were compared.Furthermore,we analyzed the relationship between the anterior communicating aneurysm and blood vessel length,diameter,shape variation,and degree of vascular curvature.Meanwhile,the similarities and differences between normal adults and anterior communicating aneurysm patients were compared.These data would provide theoretical basis and data support for studying the causes and clinical evaluation the risk of anterior communicating aneurysm.Materials and methods:1.Human specimen informationIn this study,we collected 10 normal adult head specimens from the Department of Human Anatomy,School of Basic Medical Sciences,Jilin University,including 7 males and 3 females.According to the basic operation of local anatomy,the skin and subcutaneous tissue of the head were separated to expose the skull.A hand-held craniotomy saw was used to perform a routine craniotomy along the upper nape line of the extraoccipital carina,and the rongeur was used to destroy the petrous part of the temporal bone and the bone of the skull base.Along the dura mater,skull base vessels were fully exposed,and the related anatomical structures of the anterior cerebral artery and the anterior communicating artery were measure,and their relationship was identified.2.Videography informationThis study collected data from patients who underwent head CTA enhanced scan or DSA test at the Imaging Center of the First Hospital of Jilin University from June 2019 to October 2020.According to the inclusion and exclusion criteria,we obtained 127 cases of CTA normal adults group with an average age of 49 years,including 78 males and 49females;83 cases of CTA anterior communicating aneurysm group with an average age of 55 years,including 51 males and 32 females;63 cases of DSA normal adults group with an average age of 53 years,including38 males and 25 females.According to the operating procedures of the Imaging Center of the First Hospital of Jilin University and the requirements of Discovery ^TM64-row gemstone CT and Innova 3100 imaging machine,routine data were collected.DSA used the right femoral artery inguinal to insert the needle,and the standard anterior and lateral projection were selected for the angiographic position,and the oblique projection was added if necessary.Upload the data that conformed to the inclusion criteria to the AW workstation.In the later stage,data screening and image processing were conducted by professional and technical personnel of the imaging center,and appropriate window width and window height were selected for three-dimensional reconstruction of the circulatory system and surrounding areas.Maximum intensity projection（MIP）,Multiplane recombination（MPR）,curved planar reformation（CPR）,volume rendering（VR）were used for image optimization,and the workstation’s measuring means were used for observation and data acquisition under the guidance of technical personnel.3.All the measurements were performed there times,and SPSS25.0statistical analysis software was used for statistical analysis,expressed as X±S.P<0.05 indicated that the difference was statistically significant.Results:1.There were no statistical difference between left and right length of the anterior cerebral artery A1segment in the human specimen group,DSA group,CTA normal adult group,and CTA anterior cerebral aneurysms group.However,the diameter of the left side of the anterior cerebral artery A1 segment was longer than that of the right side significantly.There was no significant difference in the length and diameter of the anterior cerebral artery A1 segment between the ipsilateral CTA normal adult group and the CTA anterior communicating aneurysm group.2.The proportion of balanced type,dominant type and absent type in CTA normal adult group were 79.5%,16.6%and 3.9%respectively;and the proportion of balanced type,dominant type and absent type in CTA anterior chiasmatic aneurysm group were 49.3%,37.3%and 13.4%respectively.3.In CTA anterior chiasmatic aneurysm group,when the anterior communicating artery was balanced type,the ratios of optic chiasm and longitudinal fissure aneurysms were 58%and 42%,respectively;when the anterior communicating artery was dominant or absent type,the ratios of optic chiasm and longitudinal fissure aneurysms were 31%and 69%,respectively.4.There were no statistical difference between left and right length of the anterior cerebral artery A2 segment in the human specimen group,DSA group,CTA normal adult group,and CTA anterior cerebral aneurysms group.There was no significant difference in the diameter of the anterior cerebral artery A2 segment between the ipsilateral CTA normal adult group and the CTA anterior communicating aneurysm group.5.The variation rate of anterior cerebral artery A2 segment in CTA normal adults and CTA anterior chiasmatic aneurysm group were 0.79%and 4.8%,respectively.6.Compared with the normal adult group and the non-aneurysm side of the aneurysm group,there were statistical differences in the angle between the A1 and A2 segments of the anterior cerebral artery and the angle between the A2 segment of the anterior cerebral artery and the anterior communicating artery in aneurysm side of the aneurysm group;there was no significant difference in the angle between the A1 segment of the anterior cerebral artery and the anterior communicating artery.7.There was no significant difference in the relative length and curvature of the A3 segment of the anterior cerebral artery in the CTA normal adult group.Conclusion:1.The occurrence of anterior communicating aneurysm was closely related to the superiority of the A1 segment of the anterior cerebral artery.When the A1 segment of the anterior cerebral artery was dominant or absent type,longitudinal fission aneurysms were more likely to happen.2.The angle between A2 segment of the anterior cerebral artery and anterior communicating artery was increased,and the angle between the A1 and A2 segments of the anterior cerebral artery was decreased,and the variations in A2 segment of the anterior cerebral artery indicating a risk of anterior communicating aneurysm.3.The relative length and curvature of the A3 segment of the anterior cerebral artery have little effect on the occurrence of anterior communicating aneurysm.