To analyze the cerebral angiographic features of anterior communicating artery aneurysms. Methods The cerebral angiographic data of 40 cases of anterior communicating artery aneurysms confirmed by surgery in our department in recent years were summarized, and the cerebral angiographic data of 76 cases of other intracranial artery aneurysms (non-anterior communicating artery aneurysms) were selected as the control; at the same time, the imaging classification of anterior communicating artery aneurysms was carried out. Results Among the 40 cases of anterior communicating artery aneurysms cerebral angiography, 33 cases had A1 dominance on one side; 24 cases in the control group had A1 dominance on one side. Conclusion A1 dominance on one side of the anterior cerebral artery has a close relationship with anterior communicating artery aneurysms, and the typing of anterior communicating artery aneurysms has important clinical significance. Data and Methods I. General information There were 40 cases of anterior communicating artery aneurysm, including 23 male cases, 17 female cases, male:female=1.4:1. the age of the largest 66 years old, the age of the smallest 26 years old, the average age of 47 years old. Cerebral angiography of other intracranial aneurysms (non-anterior communicating artery aneurysms) was selected as a control group of 76 cases, 30 males and 46 females, with an average age of 50 years. In all cases, Seldinger’s technique was used to perform bilateral internal carotid artery and vertebral artery angiography through the right femoral artery puncture and intubation, and the anterior, lateral, and oblique films were taken, and rotational and Tang’s films were taken if the relationship between the aneurysm and the peripheral blood vessels was not clear. Based on the cerebral angiography, when the diameter of the A1 segment of the anterior cerebral artery of one side is thicker than that of the A1 segment of the opposite side, the A2 segment of the anterior cerebral arteries of both sides will be visualized at the same time when the internal carotid artery of that side is imaged. The A1 segment of the contralateral internal carotid artery is thin, narrow, or occluded. We call this side of the anterior cerebral artery A1 dominance. III. Imaging typing of anterior communicating artery aneurysm According to the lateral image of cerebral angiography of anterior communicating artery aneurysm, taking the projection point of the anterior communicating artery as the origin, establishing a right-angle coordinate system, with the horizontal axis parallel to the horizontal line and the longitudinal axis perpendicular to the transverse axis, the area around the anterior communicating artery will be divided into four regions, and anterior communicating artery aneurysm will be classified into four types, that is, anterosuperior, anteroinferior, post-superior, post-inferior, according to the region in which the tumor is located. If the lateral image is not good, combine with oblique film for reference. In addition, sylvatic aneurysms and lobulated aneurysms were categorized into complex types. Statistical methods SPSS13.0 statistical software package was used for statistical analysis, X2 test was used, and P<0.05 was regarded as statistically significant. Results I. Imaging characteristics of 40 cases of anterior communicating artery aneurysms Among the 40 cases of anterior communicating artery aneurysms, there were 37 cases of saccular aneurysms, 1 case of coxal aneurysm, and 2 cases of lobular aneurysms. The maximum diameter of the aneurysm was <5mm in 10 cases, 5-15mm in 27 cases, 15-25mm in 2 cases and >25mm in 1 case. Cerebral angiography showed (see Figure 1-4): left A1 dominance in 28 cases (70%), of which the left A1 diameter was larger than the right A1 diameter in 15 cases, and the right A1 was not visualized in 13 cases; right A1 dominance in 5 cases (12.5%), of which the right A1 diameter was larger than the left A1 diameter in 4 cases, and the left A1 was not visualized in 1 case; and the basic symmetry of the bilateral A1 was found in 7 cases (17.5%). There were 2 cases of multiple aneurysms, both of which were anterior traffic aneurysms and aneurysms at the bifurcation of the right middle cerebral artery on the right internal carotid artery angiography. Comparison of A1 dominance between anterior communicating artery aneurysms and non-anterior communicating artery aneurysms In the group of 40 anterior communicating artery aneurysms, there were 33 cases of A1 dominance on one side (accounting for 82.5%), and 7 cases of basic symmetry of A1 bilaterally; and in the control group of 76 non-anterior communicating artery aneurysms, there were 24 cases of A1 dominance on one side (accounting for 31.6%), and 52 cases of basic symmetry of A1 bilaterally. The difference between the two groups was significant (P<0.05), and those with one-sided A1 dominance in anterior traffic aneurysms were significantly higher than those with non-anterior traffic aneurysms. III. Imaging results of 40 cases of anterior communicating artery aneurysms 17 cases of anterosuperior type (42.5%); 11 cases of anterosuperior type (27.5%); 5 cases of posterosuperior type (12.5%); 4 cases of posterior-inferior type (10%); 3 cases of complex type (7.5%). Discussion I. Anatomical variations and cerebral angiographic features of the anterior communicating artery complex Usually, the anterior communicating artery is the center of the complex, including the anterior cerebral artery A1 segment, A2 segment and the Heubner's artery of return, collectively referred to as the anterior communicating artery complex. There are more vascular variants in this region, with the most common developmental abnormality in the A1 segment, which occurs at a rate of 10%, and is mostly seen in the right A1 segment developmental abnormality. "A1 dominance of the anterior cerebral artery" is a sign of cerebral angiography, which indicates that the blood flow obstruction caused by the occlusion, defect, slenderness, and other complex conditions of the A1 segment of the anterior cerebral artery on one side of the cerebral artery leads to a compensatory increase in the blood flow of the A1 segment on the other side of the cerebral artery, and the formation of this sign is related to the abnormal development of the A1 segment. Therefore, anterior communicating artery aneurysms are more common on cerebral angiography with A1 dominance on the left side, and anterior communicating artery aneurysms are also more common on the left side. In this group, there were 33 cases of A1 dominance on one side in 40 cases of anterior communicating artery aneurysms, including 28 cases of A1 dominance on the left side and 5 cases of A1 dominance on the right side. The relationship between anterior communicating artery aneurysms and A1 dominance Anterior communicating artery aneurysms are often accompanied by abnormal development of the A1 segment on one side, and Kirgis[3] reported that there were 15 cases of A1 dominance in 26 cases of anterior communicating artery aneurysms. Kirgis[3] reported that A1 dominance was found in 15 out of 26 cases of anterior communicating artery aneurysm. In our anterior traffic aneurysm and control group, there were 33 cases (82.5%) and 24 cases (31.6%) of A1 dominance each. There were significantly more A1 dominant individuals in the anterior communicating artery aneurysm group than in the control group. Local vascular anatomical variations and hemodynamic changes caused by abnormal development of the A1 segment on one side are closely related to the formation of anterior communicating artery aneurysms. That is, those with dominant blood flow in the A1 segment of the anterior cerebral artery have a higher likelihood of developing anterior traffic aneurysms. The cerebral angiographic sign of "A1 dominance of the anterior cerebral artery" has been referred to by some authors [7][8] as the "trident artery sign" or "vascular pattern predisposing to the formation of anterior traffic aneurysms". The authors[7][8] called it "triple bifurcation artery sign" or "vascular pattern prone to anterior traffic aneurysm formation", and believed that those with this sign should be followed up for early detection of aneurysms, even if they do not have subpial hemorrhage. III. Typing of anterior communicating artery aneurysm Due to the variation of anterior communicating artery complex and hemodynamics, the site of aneurysm tip, the morphology and pointing of aneurysm varied greatly. The aneurysm tip can be located in the upper, lower, anterior and posterior aspects of the anterior communicating artery, and usually occurs in the bifurcation part of the vessel, which is in line with the axial direction of the dominant blood flow. The aneurysm can point in different directions due to factors such as hemodynamics and vessel wall weakness. Yasargil reported 375 anterior communicating artery aneurysms, which were categorized into five types based on intraoperative aneurysm pointing: forward, upward, backward, downward, and complex pointing. When analyzing the surgical techniques and surgical results of aneurysms with different pointing, he pointed out that the pointing of the aneurysm must be considered before separating the aneurysm, and the process of separation varies with the pointing of the aneurysm, and at the same time, he believed that the pointing of the aneurysm has an impact on the surgical results. Domestically, Liu Xiangxiang and Dai Qinshun reported 36 cases of anterior communicating artery aneurysms; according to the cerebral angiography lateral image of the aneurysm pointing classification, through the anterior communicating artery, the parallel and perpendicular lines with the base of the anterior cranial notch were drawn and the anterior communicating artery area was divided into 3 areas with a clockwise needle, and the aneurysm pointing to the 12:00-5:00 area was known as a forward developmental type, which was found in 18 cases, accounting for 50% of the cases; and the downward developmental type, which was found from 5:00-9:00, was found in 14 cases, accounting for 39 cases. The aneurysm pointing downward from 5:00 to 9:00 was the downward developing type in 14 cases (39%), and the aneurysm pointing backward from 9:00 to 12:00 was the backward developing type in 4 cases (11%). They concluded that the wing-point approach was the preferred surgical method for cases with tumors pointing downward and anteriorly. In cases with aneurysms pointing posteriorly, some of which are high-grade aneurysms, the longitudinal fissure approach is preferred to the wing point approach. Among the 40 anterior traffic aneurysms in our group, the anterior-inferior type, in which the aneurysm grows anteriorly and inferiorly, compresses the optic nerve, and care should be taken not to injure the optic nerve and its blood-supplying arteries during surgery. In this type of aneurysm, the wing-point approach is easier to expose and the surgical effect is good; in the anterior-superior type, the exposure of the aneurysm is not ideal during the wing-point approach, and sometimes it is necessary to resect a small portion of the frontal lobe to expose the aneurysm, and the exposure of the contralateral A2 segment is poor, and it is easy to injure the opposite side of the Heubner artery, and it may result in the stenosis of the contralateral A2 segment after the clenching of the aneurysm. When this type of aneurysm is accessed through the longitudinal fissure, it is easier to expose the bilateral A2 segments, and it is easy to separate the neck of the clipped aneurysm; Posterosuperior type, the aneurysm grows posteriorly, adjacent to the hypothalamus and the mouth of the corpus callosum, which makes the separation more difficult, and if it damages the hypothalamus and the corpus callosum, there will be complications, and the serious cases will lead to coma, electrolyte disorders, and have a danger to the life; Posterosuperior type, the aneurysm develops posteriorly downward, and it points to the hypothalamus and the endplate, which is a big risk for the surgery. The posterior-inferior type, in which the tumor develops posteriorly and points to the hypothalamus and the endplate, is a risky operation and is prone to damage the perforating vessels of the hypothalamus, with more complications. The number of cases of posterosuperior type, posterosinferior type and complex type in this group is relatively small. According to the cerebral angiography lateral image of anterior traffic aneurysms, sometimes the pointing of the aneurysm is complicated, not completely standardized in the above classification, but between the two types of classification. The surgical choice of wing point approach or longitudinal fissure approach is still related to the experience and habit of the operator. In conclusion, careful preoperative review of the radiographs, typing of the aneurysm, and clarification of the pointing of the aneurysm and its relationship with the surrounding blood vessels and other tissues and structures are of great clinical significance for the surgical operation and intraoperative prediction of the difficulties and estimation of the accidents.