Diagnosis of persistent primitive olfactory artery using computed tomography angiography

Persistent Primitive Olfactory Artery Aneurysm

A middle-aged adult presented to the hospital with a high-grade aneurysmal subarachnoid hemorrhage. The patient was treated with endovascular coil embolization of a ruptured basilar tip aneurysm. Angiography demonstrated multiple other aneurysms, including type I persistent primitive olfactory artery aneurysm. After complete recovery and return to independence, the patient underwent elective treatment of the persistent primitive olfactory artery aneurysm with endovascular placement of a flow diversion stent. Persistent primitive olfactory artery is an extremely rare variant of the anterior cerebral artery with an incidence of 0.14% and a known increased risk of aneurysm formation.

Anterior Cerebral Artery: Variant Anatomy and Pathology

The anterior cerebral artery (ACA) contains anatomical variants that are closely related to its embryology and development. In this study, the authors reviewed the most commonly encountered variants of the ACA and anterior communicating artery. They also reviewed the embryological origins of these variants as well as a variety of associated pathologies. Several variants are described and highlighted with illustrations including: (1) the aberrant origin of the ACA from the internal carotid artery and its developmental association with the ophthalmic artery; (2) the persistent olfactory artery; (3) the azygous ACA; (4) the triplicated ACA; and (5) multiple anterior communicating arteries. The formation of aneurysms is associated with such variants, thus their knowledge and the embryology behind their development are crucial to prevent injury to the patient.

Aneurysm of the A1 Segment of the Anterior Cerebral Artery Associated with the Persistent Primitive Olfactory Artery

BACKGROUND

The persistent primitive artery constitutes the anterior cerebral artery proper. When the persistent primitive artery keeps its embryologic course along the olfactory bulb, it is called the persistent primitive olfactory artery (PPOA).

CASE DESCRIPTION

A 69-year-old man presented with an incidentally discovered unruptured aneurysm at the origin of the PPOA. The PPOA originated at the A1 segment of the anterior cerebral artery, coursed anteromedially along the olfactory tract, made a hairpin turn posterosuperior to the midline, and formed the callosomarginal branch of the anterior cerebral artery. The anomalous artery was interpreted as a PPOA (type 3). Type 3 PPOA associated with an unruptured aneurysm is rare.

CONCLUSIONS

There is a high incidence of aneurysms associated with a PPOA. Follow-up studies are necessary in the present case to monitor for the development of another aneurysm at the hairpin bend.

Persistent primitive olfactory artery in Serbian population

The continuation of the cranial branch of the primitive internal carotid artery is called the primitive olfactory artery (POℓA). It takes this name according to the fact that it is mainly concerned with supplying the developing nasal region. We reported two new cases of the persistent POℓA (PPOℓA) in Serbian population after retrospective analysis of digital images of 200 fetal and 269 adult cases. This PPOℓA originated from the precommunicating part (A1) of the right anterior cerebral artery, coursed along the olfactory tract, and turned on the medial cerebral hemisphere in both male adults. Some vascular variations (fenestration of the A1 and the median artery of the corpus callosum) were associated with this persistent vessel. According to the fact that we did not find aneurysm in our previous and two recent cases, we are of the opinion that PPOℓA is usually asymptomatic in Serbian population.

New variant of persistent primitive olfactory artery associated with a ruptured aneurysm

The authors present the case of a 78-year-old man who presented with a subarachnoid hemorrhage due to rupture of an aneurysm at the origin of the persistent primitive olfactory artery (PPOA). Interestingly, the PPOA was originating from the A1 segment of the anterior cerebral artery and coursed anteromedially along the olfactory tract. Moreover, the PPOA in this case had 2 branches: the branch making a hairpin turn and supplying the distal part of the anterior cerebral artery territory (Type 1), and the branch extending to the cribriform plate to supply the nasal cavity (Type 2). To the best of the authors' knowledge, this is a new variant (Type 3) of PPOA associated with a ruptured aneurysm. The clinical implications of this case are discussed in terms of the embryological aspects.