The diameters of the A2 segment of the anterior cerebral artery in patients without and with intracranial aneurysms

Mirsad Zornic, Franck Emmanuel Roux, Hajrudin Kozarevic, Zlatko Ercegovic


Background: Although neurosurgical anatomy of the anterior cerebral arteries (ACAs) has been well described, most diagnostic brain procedures and techniques have used morphometric data regarding the diameter of the A2 segment based on measurements derived from cadaveric studies.

Aim: To analyze the internal diameter of the A2 segment of the ACA based on CT angiography (CTA) in individuals with and without intracranial aneurysms.

Methods: We analyzed CT angiograms of 278 individuals; 143 without aneurysms (83 males and 60 females, mean age 56,21) and 135 subjects harbouring intracranial aneurysm. Data analysis included inner diameters and vascular asymmetry coefficient (VAC) of the A2 segment of ACAs.

Results: In male subjects, the mean internal diameter (ID) in the aneurysm group was 2.01 mm for the left side and 1.99 mm for the right side, respectively. In the group with aneurysms the mean ID was 2.09 mm on the left side and 2.07 mm on the right side, respectively. In females, in the group without aneurysms, the mean ID was 1.92 mm on the left side and 1.94 mm on the right side. In the aneurysm group the mean ID was 2.07 mm on the left and 2.09 mm on the right side, respectively. In the group without aneurysms, males have had larger mean ID, but in the aneurysm group, there was no significant difference in mean ID. Insignificant difference was noted between sides in males not harbouring aneurysms. Likewise, females not harbouring aneurysms showed insignificantly larger mean ID at the right side. A2 segment was symmetrical in 98% individuals, without gender difference. The mean ID of the A2 segment did not change in respect to age.


Conclusion: A detailed knowledge regarding the arterial diameter is important when planning and performing cerebrovascular or interventional procedures. Values of diameter, presented herein may provide reference values specific for normal individuals and, also, for individuals with intracranial aneurysms.


anterior cerebral artery; A2 segment; diameter; CT angiography; intracranial

DOI: 10.5457/ams.v42i1.317