Relationship between the morphology of A-1 segment of anterior cerebral artery and anterior communicating artery aneurysms

Background: The anterior communicating artery (ACoA) is one of the most frequent sites for cerebral aneurysm. The peculiar directions of projection of aneurysms offer great challenges to clinical treatment. Objetives: To establish the relationship between morphology of A-1 segment of anterior cerebral artery (ACA) and aneurismal projection. Methods: Randomly selected digital subtraction angiography data of 264 anterior communicating artery aneurysms (ACoAA) cases and 296 cases of other cerebral vascular diseases in the same period were retrospectively analyzed. Results: Among 264 ACoAA patients, the morphology of A-1 segment showed type 1a in 158 sides, type 1b in 11, type 2a in 35, type 1 2b in 87, type 3 in 171 and absence in 66. The morphology of A-1 segment in 296 patients with other cerebral vascular diseases displayed type 1a in 195 sides, type 1b in 20, type 2a in 47, type 2b in 74, type 3 in 217 and absence in 39. The non-visualization of A-1 segment in the group of ACoAA occurred more than in the control group (chi(2) = 11.482, p = 0.001). The classifications of ACoAAs in 264 patients were confirmed as anterior-superior type in 121 cases, anterior-inferior type in 105, complicated type in 16, posterior-inferior type in 12 and posterior-superior type in 10. The correlation between morphology of A-1 segment of ACA and classifications of ACoAA was significant (p = 0.000; C = 0.619, p = 0.000). The direction of ACoAA was downward when the A-1 segment of ACA was Type 1a or Type 2a, and was upward when it was Type 1a or Type 2a and was upward or downward or complicated when it was Type 3. Conclusion: The relationship between morphology of A-1 segment of ACA and classification of ACoAA is clarified in the present study, which is helpful to surgical treatment.