Persistent primitive olfactory artery: MR angiographic diagnosis

Persistent Primitive Olfactory Artery Type 4 with Fusiform Aneurysm: A Case Report

The persistent primitive olfactory artery (PPOA) is a rare variant of the anterior cerebral artery, first reported in 1979. It reportedly has a high correlation with the development of aneurysms, owing to the hemodynamic stress induced by the structural characteristics of the hairpin turn. Herein, we present a rare case of PPOA type 4 with a fusiform aneurysm at the hairpin turn segment in a 46-year-old female with occasional headaches. Time-of-flight MR angiography and transfemoral cerebral angiography revealed an unusual branch arising from the left A1 segment, running anteromedially along the ipsilateral olfactory tract, and turning the hairpin posterior to the olfactory bulb. This branch continued into the left accessory middle cerebral artery, and a fusiform aneurysm was observed at the hairpin segment. No further treatment was performed, and follow-up imaging was recommended. Nevertheless, it is essential to recognize and diagnose these rare variations.

Bilateral Persistent Primitive Olfactory Arteries Observed During Resection of Olfactory Groove Meningioma: Technical Case Report

BACKGROUND AND IMPORTANCE

Resection of olfactory groove meningiomas is challenging because of their close proximity with the anterior cerebral circulation. It is important to recognize the vascular variants in procedures at the anterior skull base because inadvertent maneuvers may result in the rupture of these arteries and unexpected bleeding.

CLINICAL PRESENTATION

We reported a type 2 persistent primitive olfactory artery with a dural branch of the elongated anterior cerebral artery directly to the ethmoid region, visualized during the surgical removal of an olfactory groove meningioma.

CONCLUSION

This is the first report of bilateral persistent primitive olfactory artery demonstrated by operative visualization and confirmed with vascular study. Understanding and recognizing the possible variations of this vascular anatomy is of great importance for anterior skull base surgeries.

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.

Orbitofrontal artery arising from a hairpin turn in type 1 persistent primitive olfactory artery: a possible new variant (type 6)

PURPOSE

To describe a case of a possible new variant of persistent primitive olfactory artery (PPOA).

CASE REPORT

A 93-year-old man with left hemiparesis and dysarthria underwent cranial magnetic resonance (MR) imaging and MR angiography using a 3-T scanner. MR imaging showed an acute infarction at the right precentral gyrus. MR angiography showed no steno-occlusive lesions, but the distal A1 segment of the left anterior cerebral artery (ACA) took an extreme anterior course and made a hairpin turn, connecting to the A2 segment, which is indicative of type 1 PPOA. In addition, there was a faintly visualized small artery arising from the hairpin turn. Subsequent computed tomography (CT) angiography showed that the hairpin turn had a mildly dilated arterial lumen, and an extremely tortuous orbitofrontal artery arose from the hairpin turn.

DISCUSSION

There are five types of PPOA. Type 1 is most common, and usually no arterial branch arises from the hairpin turn, except for in type 3 PPOA, which has a branch continuing to the anterior ethmoidal artery arising from the hairpin turn. Using MR and CT angiography, we diagnosed a case of type 1 PPOA associated with the orbitofrontal artery arising from a hairpin turn. A similar previously reported case was diagnosed using catheter angiography.

CONCLUSION

The present case may be a new variant (type 6) of PPOA. Because the orbitofrontal artery was relatively small in caliber and its proximal segment extremely tortuous, CT angiography had superior utility to MR angiography for demonstrating this variation.

Bilateral persistent primitive olfactory arteries associated with an accessory anterior cerebral artery

Persistent primitive olfactory artery (PPOA) is a relatively rare variation of the proximal anterior cerebral artery (ACA) that generally follows an extreme anteroinferior course and takes a hairpin turn before continuing to the A2 segment of the ACA. This variation is usually seen unilaterally, and the anterior communicating artery (ACoA) is usually long or absent. We herein report a case of bilateral persistent PPOAs associated with an accessory ACA. The length of the bilateral A1 segments was normal and the length of the ACoA was normally short. Thus, hypoplasia of the distal A1 segment is important but not necessary for the formation of the PPOA. To our knowledge, no similar cases have been reported in the relevant English language literature.

Type 4 persistent primitive olfactory artery associated with contralateral accessory middle cerebral artery arising from the fenestrated segment of the distal anterior cerebral artery

Persistent primitive olfactory artery (PPOA) is a rare variation of the proximal anterior cerebral artery (ACA) that generally follows an extreme anteroinferior course and takes a hairpin turn before continuing to the A2 segment of the ACA (type 1). There are four other types of extremely rare variations. The type 4 variation continues to the accessory middle cerebral artery (MCA) instead of the ACA. Only a few cases have been reported. We herein report a case of type 4 PPOA in which the contralateral side of the accessory MCA arose from the fenestrated segment of the distal ACA. No similar cases were found in the relevant English-language literature. For the identification of these variations on MR angiography, volume-rendering images were superior to maximum-intensity-projection images.

Type 2 persistent primitive olfactory artery associated with bilateral ophthalmic arteries arising from the middle meningeal arteries diagnosed by magnetic resonance angiography

Persistent primitive olfactory artery (PPOA) is a relatively rare variation of the proximal anterior cerebral artery (ACA). Traditionally, there are two types: Type 1 is a common type, which generally follows an anteroinferior course and which takes a hairpin turn before continuing to the A2 segment of the ACA. Type 2 is an extremely rare variation that continues to the anterior ethmoidal artery without a hairpin turn. Since Type 2 PPOAs are small in caliber, previously reported cases were found during anatomical dissection or were detected by catheter angiography. We herein report a case of Type 2 PPOA that was diagnosed by partial-maximum-intensity projection images of magnetic resonance angiography. This patient also had bilateral ophthalmic arteries arising from the middle meningeal artery. These two variations may be related to each other.

Coil embolization of subarachnoid hemorrhage with ruptured persistent primitive olfactory artery aneurysm

Background:

Persistent primitive olfactory artery (PPOA) is a rare anomaly of the anterior cerebral artery. We experienced a rare case of subarachnoid hemorrhage caused by a ruptured saccular aneurysm of PPOA.

Case Description:

A 72-year-old man was transported to our hospital with sudden headache. On examination, World Federation of Neurological Surgeons scale was Grade I, and computed tomography of the head showed subarachnoid hemorrhage in Fisher Group 3. Cerebral angiography showed left PPOA and a 4-mm saccular aneurysm at the hairpin turn. No other abnormalities causing bleeding were observed. Based on these findings, subarachnoid hemorrhage due to a ruptured PPOA aneurysm was diagnosed. As the patient had a ventilatory defect due to emphysema, direct approach to the lesion would have been difficult and an endovascular surgery was performed. Three coils were inserted into the aneurysm, and complete occlusion was achieved. Cerebral vasospasm was not observed, and the patient was discharged 1 month after surgery without any neurologic deficit.

Conclusion:

Most aneurysms of the PPOA are formed at the hairpin turn, as observed in our patient; therefore, a hemodynamic mechanism may be involved in the etiology. To the best of our knowledge, there is no report on treatment using intra-aneurysmal coil embolization, indicating that ours was the first case. As the long-term outcome of intra-aneurysmal coil embolization for PPOA aneurysm is unknown, careful follow-up will be necessary in the future.

Persistent primitive olfactory artery associated with early bifurcated accessory anterior cerebral artery

Five types of persistent primitive olfactory artery (PPOA), a rare variation of the proximal anterior cerebral artery (ACA), have been reported. Type 1 is most common, generally following an extreme anteroinferior course and taking a hairpin turn before continuing to the distal A2 segment of the ACA. Triple ACAs are a common variation of the A2 segment of the ACA, and a centrally located artery is called an "accessory ACA" or "median artery of the corpus callosum". This artery usually does not bifurcate or else bifurcates distally and continues to the pericallosal artery. We herein report a 74-year-old woman with type 1 PPOA and early bifurcated accessory ACA, an extremely rare combination of ACA variations, that was diagnosed using magnetic resonance angiography.

Persistent Primitive Olfactory Artery: Three Cases

ABSTRACT

The persistent primitive olfactory artery is a very rare arterial variant with a little over a score of cases reported in literature so far. We present 3 cases illustrating this entity, which were incidentally diagnosed while imaging for other indications.

A1 Segment Unruptured Aneurysm of Persistent Primitive Olfactory Artery Coexisted with Accessory Middle Cerebral Artery

A persistent primitive olfactory artery (PPOA) is a rare anomaly of anterior cerebral artery (ACA), which generally arises from the internal carotid artery (ICA), runs along the olfactory tract, and makes a hairpin bend to supply the territory of the distal ACA. PPOA is also associated with cerebral aneurysms. An accessory MCA is a variant of the middle cerebral artery (MCA) that arises from either the proximal or distal portion of the A1 segment of the ACA, which runs parallel to the course of the MCA and supplies some of the MCA territory. We experienced a rare case of coexistence of PPOA with an unruptured aneurysm and accessory MCA. Three-dimensional computed tomographic angiography (3D-CTA) has an excellent picture of the spatial relationship of the surrounding bony and vascular structure.

Combined rare anatomic variants: persistent primitive olfactory artery and azygos pericallosal artery

The persisting primitive olfactory artery (PPOA) is a rare anatomic variation of the anterior cerebral artery (ACA), being encountered in less than 1% of cases. Different morphological types were reported previously. In type 3, only once reported previously, the PPOA gives off two branches, a nasal one which courses in the olfactory sulcus to supply the territory of the anterior ethmoidal artery, and the callosomarginal artery. It is reported here a combination of rare anatomic variants found in a 71-year-old male patient investigated by computed tomography angiography. A left PPOA left the A1 segment of the ACA and was classified as subtype 3b, as its branches were the nasal one and a frontal trunk, not the callosomarginal artery. That PPOA had a characteristic hairpin turn applied on the anterior fossa floor. The ACA continued as azygos pericallosal artery, which is also a rare finding. As the nasal branch of the PPOA and its hairpin turn is closely related to the anterior fossa floor, such variant should be carefully documented when combined approaches of the skull base are planned by rhinologists and neurosurgeons.

Persistent primitive olfactory artery without a hairpin turn

Persistent primitive olfactory artery (POA) is a relatively rare variation of the proximal anterior cerebral artery (ACA) that generally follows an extreme anteroinferior course and takes a hairpin turn before continuing to the A2 segment of the ACA. There are other extremely rare variations, such as (1) that continuing to the ethmoidal artery without a hairpin turn, (2) that continuing to both ethmoidal artery and distal ACA with a hairpin turn, and (3) that continuing to the accessory middle cerebral artery with a hairpin turn. We herein report a case of persistent POA without a hairpin turn continuing to the A3 segment of the ACA. We propose calling this new type of persistent POA Type 5.

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.

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.

Normal pio-dural arterial connections

The arterial blood supply to the dura mater is rich, complex and is derived from both the internal and external carotid systems. Endovascular management of a variety of intracranial diseases necessitates a thorough understanding of the dural arterial network. In this article we review the normal contributions of the pial arteries to the blood supply of the dura mater and discuss some aspects of its role in the supply of dural arteriovenous shunts (DAVS).

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: CT angiographic diagnosis and literature review for classification and clinical significance

OBJECTIVES

The aim of this study was to investigate the incidence of a persistent primitive olfactory artery (POA) and to review the literatures focusing on the classification and clinical significance of this variant.

DESIGN

To identify cases with persistent POA, we reviewed the records of computed tomography (CT) angiography performed on 3,067 patients in our institution from January 1, 2011 to August 31, 2013. Literatures on the incidence and classification of a persistent POA were reviewed.

RESULTS

Among these patients, eight were diagnosed with a persistent POA (five men, three women, aged 44-82 years), an incidence of 0.26 %. Six persistent POAs terminated as a distal anterior cerebral artery (ACA) and two as a distal middle cerebral artery. Previous studies applied similar definitions for the classification of persistent POA; however, there has been confusion on the definition of variant 2.

CONCLUSION

In our institution, the incidence of persistent POA seen on CT angiography was 0.26 %. An artery with its embryological course along the olfactory bulb should be classified as a persistent POA and differentiated from dural artery from ACA.

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.

Persistent primitive olfactory artery connected with middle cerebral artery: case report

A persistent primitive olfactory artery (PPOA) is an extremely rare variation of the proximal anterior cerebral artery (ACA). The PPOA is connected to the distal ACA, ethmoidal artery, or both. I describe one patient with a PPOA connected to the middle cerebral artery (MCA). I analyzed the radiological characteristics of this anomalous vessel in this patient, who presented with headache. Computed tomography–angiography revealed an abnormal vessel in the patient, which originated from the distal ACA and ran anteromedially along the olfactory tract; it then made an abrupt turn and became the MCA. A PPOA connected to the MCA has been described in only two patients, including my own, in the English-language literature.

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.