Ruptured aneurysm at the origin of the median artery of the corpus callosum associated with accessory middle cerebral artery--case report

Embryology of the anterior communicating artery complex: implications on possible adult variants

The anterior cerebral artery (ACA) and the anterior communicating artery (AComA) are important arteries of the telencephalon and are prominent location for cerebral aneurysms. Their embryological development is closely linked, and explains the possible variants seen in adults. In this paper, we present details related to the development of these two arteries, focusing on some variants such as the infra-optic course of the ACA, the unpaired ACA, and the persistent primitive olfactory artery.

Multiple cerebral arterial variations incidentally detected by magnetic resonance angiography: a case report

We herein report a case of multiple variations, including (1) anterior communicating artery duplication, (2) accessory anterior cerebral artery (ACA), (3) distal origin right accessory middle cerebral artery (MCA) with bifurcation, (4) proximal origin left accessory MCA with bifurcation, (5) right superior cerebellar artery (SCA) duplication, and (6) left SCA early bifurcation. These variations were found incidentally by magnetic resonance (MR) angiography. Volume-rendering images of MR angiography were more useful than maximum-intensity-projection images for identifying these variations, especially bilateral accessory MCAs, which were superimposed with the A1 segment of the ACAs and the M1 segment of the MCAs.

A Median Artery of the Corpus Callosum

The anterior communicating artery is one of the main components of the vascular network that delivers blood to the brain. Therefore, a good understanding of the normal anatomy and its variations is important to neurologists, neurosurgeons, and other health care providers dealing with the central nervous system. Here, we present a case of a median artery of the corpus callosum found in a cadaver, with consideration of cerebral hemodynamics implications.

Aneurysm of a duplicate middle cerebral artery

BACKGROUND

Anatomic middle cerebral artery (MCA) anomalies are rare, but each of the described variants (eg, duplicate, fenestrated, accessory) can be of clinical significance.

CASE DESCRIPTION

A 34-year-old man with a history of left hemispheric stroke was found to have an aberrant, early-arising duplicate left M1 segment of the MCA with an associated asymptomatic fusiform aneurysm. The patient was treated with a superficial temporal artery (STA) to distal MCA bypass followed by surgical trapping of the aneurysm.

RESULTS

Intraoperative and follow-up angiography performed postoperatively at 3 months showed complete isolation of the aneurysm from the circulation and patency of the bypass graft. The postoperative course was uneventful with the exception of a craniotomy flap infection, which was effectively managed with intravenous antibiotics, flap removal, and subsequent use of a fabricated replacement.

CONCLUSIONS

This rare case is presented and used as a framework for a brief discussion of the literature regarding both variant MCA anatomy and treatment considerations for these anomalies when associated with an aneurysm.

Transient ischemic attack associated with stenosis of accessory middle cerebral artery: a case report

Accessory middle cerebral artery (MCA) is a rare anatomical variation of middle cerebral artery branching. An association of the accessory middle cerebral artery and cerebral aneurysms had been well documented. We report a patient who presented with transient ischemic attack (TIA) associated with stenosis of the accessory MCA ostium.

The Accessory Middle Cerebral Artery: Anatomic Report

Objective:

An accessory middle cerebral artery (MCA) usually originates between the A1 and proximal A2 segment of the anterior cerebral artery, reaches the sylvian fissure, and supplies the territory of the MCA. This anomaly has been associated with cerebral aneurysms and Moyamoya disease. We report an accessory MCA arising from the A2 segment.

Methods:

A cadaveric head, fixed in formalin solution and injected with red and blue silicone on its vascular tree to trace intracranial and extracranial vessels, was dissected.

Results:

An accessory MCA was found arising from the A2 segment of the anterior cerebral artery and feeding the basal and inferior surface of the inferior frontal gyrus. In our specimen, the vessel was associated with intracranial aneurysms at other locations.

Conclusion:

Although anomalies of the MCA are rare, neurosurgeons must be familiar with such anatomic variations. An accessory MCA can be associated with Moyamoya disease and aneurysms at its junction with the anterior cerebral artery. Patients with this anomaly may, therefore, have an increased risk for developing aneurysms and other neurovascular complications. By obstructing the surgical view, an accessory MCA may increase the difficulty of exposing lesions in the vicinity of the optic chiasm.

Anterior cerebral artery variations detected by MR angiography

INTRODUCTION

From anatomical and angiographic studies, it is well known that there are several variations of the anterior cerebral artery (ACA). However, ACA variations have rarely been studied by magnetic resonance (MR) angiography. The purpose of this study was to investigate not only the type, location, configuration, and incidence of ACA variations, but also coexisting arterial pathology such as aneurysms detected by cranial MR angiography.

METHODS

We retrospectively reviewed cranial MR angiography images of 891 patients at our institution. All images were obtained with one of two 1.5-T scanners using the three-dimensional time-of-flight technique. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed these horizontal MIP images, inferosuperior MIP images, and source images, and identified variations of the ACA.

RESULTS

We found 50 instances (5.6%) of unilateral A1 segment aplasia, 27 (3.0%) of three A2 segments, 18 (2.0%) of an unpaired A2 segment, and 11 (1.2%) fenestrations of the A1 and/or A2 segment. Seven anterior communicating artery (ACoA) aneurysms and one ACA territory embolic infarction were found among the 50 patients with unilateral A1 segment aplasia. One ACoA aneurysm and one pericallosal infarction were found in the 27 patients with three A2 segments. Two distal ACA aneurysms were detected among the 18 patients with an unpaired A2 segment. No associated aneurysm was seen at the fenestrations.

CONCLUSION

Although the clinical significance of ACA variations is usually minor, an associated aneurysm is found relatively frequently. Thus, recognizing ACA variations during the interpretation of cranial MR angiograms is important.