Ruptured Aneurysm Arising From the Proximal End of an Azygos Anterior Cerebral Artery-Case Report-

Abstract

A 59-year-old woman presented with subarachnoid hemorrhage. Conventional angiography and threedimensional computed tomography (3-D CT) angiography showed a saccular aneurysm at the junction of the azygos anterior cerebral artery (ACA) and the left A 1 segment. This aneurysm was associated with a fenestration of the right hypoplastic A 1 segment. The aneurysm neck was completely clipped, preserving the azygos ACA and other perforators. Aneurysm of the azygos ACA is almost always located at the distal bifurcation, and rarely at the proximal end. Proximal azygos ACA aneurysm can mimic anterior communicating artery aneurysm. Therefore, accurate preoperative diagnosis is critical using 3-D CT angiography as well as conventional angiography, and close follow up of patient is necessary to monitor for development of a de novo aneurysm at the distal bifurcation of the azygos ACA.

Ruptured Saccular Aneurysm Arising from Fenestrated Proximal Anterior Cerebral Artery : Case Report and Literature Review

“…The overall incidence of azygos ACA is ranged from 0.22% to 1.1%2). There are two theories for azygos ACA formation.…”

Coil Embolization of a Traumatic Intracranial Aneurysm of the Distal Part of the Azygos Anterior Cerebral Artery Followed Up for 4 Years -Case Report-

“…2) Azygos ACA is closely associated with the occurrence of saccular aneurysm, with an incidence ranging from 41% to 71%, because of the abnormal development or resultant hemodynamic stress. 6,7) Almost all aneurysms of the azygos ACA are located at the distal bifurcation of the artery. 12) The mechanism underlying the formation of a traumatic aneurysm in the distal part of the ACA involves shearing forces at the time of injury compressing the pericallosal artery, which is a very common site for aneurysm formation on the azygos ACA, against the stationary falcine edge, causing brain shift and resulting in the formation of traumatic aneurysm at this location.…”

Three-Dimensional Angiographic Demonstration of Plexiform Fenestrations of the Proximal Anterior Cerebral Artery Associated with a Ruptured Aneurysm

“…There have been 60 reported cases of fenestration of the anterior cerebral artery (ACA) 3,4,6) , and the incidence of fenestration of the ACA is about 0.2-7.2% in autopsy specimens 1,2) . The incidence of fenestration of the intracranial vessels is 0.3-0.9% on angiogram, and they are frequently located in the basilar and vertebral arteries 7,10) .…”

“…The embryologically normal fusion process or normal regression would make such fenestrations disappear, but incomplete fusion or abnormal regression might result in a fenestration or plexiform remnant 9) . Most of the A1 fenestrations reported thus far have been single 3,4,6,10) fenestrations, with double 8,12) fenestrations being reported only on rare occasions. In our case, the fenestrations were multiple and resembled a plexiform network in the distal end of the A1, which may strongly support the theory described by Padget 9) , namely that a remnant of the plexiform anastomosis between the primitive olfactory artery and the A1 segment is the source of such fenestrations.…”

“…Fenestration of the anterior cerebral artery (ACA) is rare [1][2][3][4]6,8) and is often associated with cerebral aneurysms 3,6,8,10) . Although the pathogenesis of A1 fenestrations has not been well described, a remnant of an embryonic plexiform anastomosis between the primitive olfactory artery and the ACA or abnormal regression are well accepted explanations for the formation of A1 fenestrations 8,11) .…”