Infraoptic anterior cerebral artery: case series report and literature review

The Infraoptic or Infrachiasmatic Course of the Anterior Cerebral Artery Emerging an Elongated Internal Carotid Artery

(1) Background: The normal A1 segment of the anterior cerebral artery (ACA) has a supraoptic course. The proximal infraoptic course of an A1 segment leaving the internal carotid artery (ICA) near the origin of the ophthalmic artery is a rare possibility. This study aimed to determine the prevalence and detailed anatomy of infraoptic A1 segments. (2) Methods: We retrospectively studied 145 computed tomography angiograms from 92 male and 53 female cases, with ages varying from 61 to 78 y.o. (3) Results: In 21/145 cases, infraoptic or infrachiasmatic horizontal-medial courses of A1 segments that emerged distally from the ICA were found. Distal infraoptic A1 segments were bilateral in 16/145 cases and unilateral in 3/145 cases. Infrachiasmatic A1 segments were found bilaterally in 2/145 male cases. All the infraoptic/infrachiasmatic A1 segments left long ICAs with low bifurcations. In 7/34 sides with distal infraoptic or infrachiasmatic A1 segments, supracarotid courses were present. In one female, the right A1 segment had an anterior supraclinoid, supracarotid and infraoptic course. In two female cases with a bilateral distal infraoptic A1, the segment was almost contacting the respective posterior cerebral artery. (4) Conclusions: In cases with dolicho(ectatic) ICAs, the A1 segments could have infraoptic and supracarotid courses the neurosurgeons should be aware of.

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.

Anterior cerebral artery trifurcation with infraoptic origin and contralateral A1 segment absence

PURPOSE

To describe an uncommon anatomical variant of the anterior cerebral artery and the imaging findings.

METHODS

A 2-month-old infant with known history of atrial and ventricular septal defects was admitted to our institution for evaluation and management of growth failure. Given the clinical presentation and medical history, magnetic resonance imaging (MRI) of the brain and MR angiography (MRA) were performed to exclude congenital hypopituitarism and any vascular abnormality.

RESULTS

Time of flight MRA revealed trifurcation of the anterior cerebral artery with one of the vessels arising from the ophthalmic segment of the right internal carotid artery; thus, the A1 segment of the left anterior cerebral artery (ACA) was absent, and the right posterior cerebral artery (PCA) had a fetal origin.

CONCLUSION

Anatomical variants of the cerebral circulation are asymptomatic and found incidentally. Knowledge of these variants and careful examination of CT/MRI angiograms are important for diagnosis and treatment planning.

An MRI study of typical anatomical variants of the anterior communicating artery complex

PURPOSE

This magnetic resonance imaging study examined the most frequent anatomical variants of the anterior communicating artery (ACoA) complex of the cerebral arterial circle, and aimed to determine whether they were associated with ACoA complex aneurysm.

METHODS

The study enrolled 669 patients. Using three-dimensional time-of-flight magnetic resonance angiography, 617 patients were classified into the following groups based on the anatomical variation in the ACoA complex: no ACoA complex anomaly; ACoA complex aneurysm; and vascular anomaly distant from the cerebral arterial circle.

RESULTS

Of the 617 classified subjects, the classical anatomical description applied to 48.73% in the no ACoA complex anomaly group and 37.5% in the ACoA complex aneurysm group. One variant (left anterior cerebral artery segment A1 hypoplasia) was significantly more frequent in the ACoA complex aneurysm group. There was no sex difference in the prevalence of any variant.

CONCLUSIONS

Anatomical variants of the ACoA complex of the cerebral arterial circle were found in almost half of the subjects. One variant seemed to be associated with a higher likelihood of an aneurysm, but causality could not be inferred.

Infraoptic anterior cerebral artery or carotid-anterior cerebral artery anastomosis: A very rare embryological variation. Case series and review of literature

PURPOSE

An infraoptic course of the anterior cerebral artery (ACA) is a rare cerebrovascular variation that can be associated with anterior communicating artery aneurysm. The purpose of this study is: 1. Describe infraoptic ACA or Carotid-ACA anastomosis. 2. Discuss the embryology. 3. Demonstrate this rare variation on CT/MR angiography. 4. Discuss its clinical significance. 5. Understand the anatomy for appropriate management of associated vascular pathology (Anterior communicating aneurysm). 6.

LITERATURE REVIEW

METHODS

We describe 2 cases with CT/MR angiographic findings of this rare vascular variation along with review of embryology and literature.

RESULTS AND CONCLUSION

Generally, ACA arises from the internal carotid artery (ICA) terminus and runs medially superior to the optic nerves and communicates with contralateral ACA through the anterior communicating artery. An infraoptic course of the A1 segment of the ACA is associated with a low ICA bifurcation, usually located intradurally at or just above the level of the origin of the ophthalmic artery. Rarely, infraoptic origins of A1 are proximal or at the level of origin of the ophthalmic arteries and arise below the optic strut possibly extradurally. Abberant ACA course has been shown to be associated with aneurysms which needs prompt recognition, to allow optimum treatment planning (surgical/endovascular). Our first case has bilateral infraoptic ACA seen on CT angiography. The second case has ipsilateral (right) infraoptic ACA with associated anterior communicating artery aneurysm.

Carotid-anterior cerebral artery (ACA) anastomosis associated with azygos ACA and ophthalmic artery arising from the middle meningeal artery: a case report

Among variations of the anterior cerebral artery (ACA), anastomosis of its A1-A2 junction with the ophthalmic segment of the internal carotid artery is rare and described as carotid-ACA anastomosis or infraoptic course of the ACA. One common variant, an azygos ACA, demonstrates no pairing of the A2 segment. To our knowledge, association of a carotid-ACA anastomosis with an azygos ACA is not reported in the English-language literature. We report a case diagnosed by magnetic resonance angiography in which right carotid-ACA anastomosis was associated with an azygos ACA and the right ophthalmic artery originated from the middle meningeal artery.

[Combination of infraoptic anterior cerebral artery with an aneurysm of the ACA-AcomA complex. Case study and literature review]

The infraoptic anterior cerebral artery (ACA) is an abnormal vessel that usually is a bifurcation of the intradural part of the internal carotid artery (ICA) or near the site of discharge of the ophthalmic artery, which passes under the ipsilateral optic nerve and penetrates between the optic nerves into the prechiasm cistern, reaching the ACA-AcomA complex. The infra-optic ACA is an extremely rare anomaly, but it may be of great clinical significance in surgery of the arteries of the anterior sections of the Willis circle. The article describes the case of a combination of infra-optical ACA with an aneurysm of the ACA-AcomA complex. This observation is of interest both from the viewpoint of the rarity of the considered pathology and the associated increased risk of the formation of intracranial aneurysms.

Bilateral carotid-anterior cerebral artery anastomoses associated with bilateral ophthalmic arteries arising from the anastomotic arteries diagnosed by magnetic resonance angiography: a case report

Rarely, the anterior cerebral artery (ACA) arises from the ophthalmic segment of the internal carotid artery, a condition described as carotid-ACA anastomosis or infraoptic course of the ACA that generally demonstrates right-sided predominance. We diagnosed a case of bilateral anastomoses of the carotid and ACA vessels in which bilateral ophthalmic arteries arose from the origins of the anastomotic vessels using magnetic resonance (MR) angiography. Identification of rare arterial variations on MR angiography requires careful scrutiny of source images, and creation of partial volume-rendering images can aid visualization of detailed anatomic structures.

Anomalies and Normal Variants of the Cerebral Arterial Supply: A Comprehensive Pictorial Review with a Proposed Workflow for Classification and Significance

Cerebral arteries may exhibit a wide range of variation from normal anatomy, which can be incidentally discovered during imaging. Knowledge of such variants is crucial to differentiate them from pathologies, to understand the etiology of certain pathologies directly related to a vascular variant, and to depict the changes in collateral circulation in patients with certain variants. Detection of particular variants may lead to the discovery of other nonvascular or vascular anomalies, especially aneurysms, and may also affect planning of endovascular or neurosurgical interventions. In this review, we summarize the variants and anomalies of cerebral arteries seen on cross-sectional imaging classified by a morphological approach and categorize their significance from a clinical perspective. This structured review is intended to serve as a guide for daily use in clinical practice.

Multiple variations of the cerebral arteries associated with tetralogy of Fallot: a case report

Tetralogy of Fallot (TOF) can be associated with vascular malformations or variations, especially of the aortic arch or supracardiac major venous systems. We report its association with an extremely rare combination of three such variations of the cerebral arteries-a right persistent hypoglossal artery, an extremely rare left carotid-right anterior cerebral artery (ACA) anastomosis, and a left accessory middle cerebral artery arising from the A1-A2 junction of the left ACA-which were diagnosed by magnetic resonance angiography in a 9-year-old girl during evaluation of multiple acute cerebral infarctions.