Persistent fetal intracranial arteries: a comprehensive review of anatomical and clinical significance

Bilateral concurrent type I and type II persistent proatlantal arteries: A case report

Transient embryonic carotid-vertebrobasilar anastomoses can intermittently persist beyond the embryonic period. These vascular anomalies are often serendipitously identified during evaluation for unrelated disease states and pathologies. The persistent proatlantal intersegmental artery is one such recognized rare fetal anastomotic connection, often arising unilaterally. Bilateral persistence of the proatlantal anastomosis is a rarer occurrence, seldom described in the literature. We report a case of bilateral concurrent type I and type II proatlantal arteries, describe the embryology of persistent carotid-vertebrobasilar anastomoses, and consider pertinent clinical implications.

Watershed cerebral infarction in a patient with a persistent primitive trigeminal artery and contralateral internal carotid artery stenosis: A case report

Patients with a persistent primitive trigeminal artery frequently have a poorly developed vertebrobasilar arterial system. However, they are not at higher risk of stroke and most are asymptomatic. Left cerebral watershed infarction was identified in a 75-year-old man who presented with aphasia and disorientation on magnetic resonance image (MRI). Additional imaging studies also demonstrated a right persistent primitive trigeminal artery, aplastic basilar artery, and 47% left internal carotid artery stenosis. Antiplatelet medication was administered and he was discharged 2 weeks after admission on aspirin. At the 4-month follow-up, cerebral blood flow in the left watershed territory was still decreased; however, no recurrent stroke had occurred. Although the indication for surgical or endovascular intervention for internal carotid artery stenosis is primarily determined by the degree of stenosis, cerebral blood flow evaluation is recommended in patients with internal carotid artery stenosis and a persistent primitive trigeminal artery.

Middle meningeal artery arising from the petrous internal carotid artery: Outcome of unusual stapedial artery regression

Background

The internal and external carotid arterial systems are generally separate regarding branching patterns. However, these two systems do form collateral circulations with their terminal parts. On rare occasions, branches that belong to one arterial system may arise from the other.

Case Description

We present a rare variant of a middle meningeal artery, generally derived from the external carotid artery, arising from the internal carotid artery and entering the floor of the middle cranial fossa by traveling through a small unnamed foramen. This anatomy and embryology and other variants of the middle meningeal and petrous carotid systems are discussed.

Conclusion

Embryologically, this variant anatomy signifies an atypical regression of the distal stapedial artery and its connection to the external carotid artery. Surgeons who operate on the skull base, vascular interventionalists, and radiologists should be aware of this potential anatomical variation of the skull base.

Disappearing Cerebral Communicating Vessels in Embryonic Development-With a Case of Carotid-Vertebrobasilar Artery Anastomosis

In early embryonic development, anastomoses between carotid and basilar arteries occur in the primitive trigeminal, primitive otic, primitive hypoglossal, and primitive proatlantal arteries, and these anastomoses gradually disappear as the embryo continues to develop. This article reported a case of vascular anastomosis occurring between the external carotid artery and vertebral artery.

Mechanical Thrombectomy for Basilar Artery Occlusion with a Type 1 Persistent Proatlantal Artery: A Case Report and Literature Review

Objective

Persistent proatlantal artery (PPA) is a primitive carotid-vertebrobasilar anastomosis (CVA); acute ischemic stroke due to basilar artery (BA) occlusion via a PPA is extremely rare.

Case Presentation

An 84-year-old female developed disturbance of consciousness (Glasgow Coma Scale E2V1M5) and quadriparesis with a National Institutes of Health Stroke Scale score of 35. Head CT revealed early ischemic changes in the right temporal lobe, and a hyperdense vessel sign in the BA. Cerebral angiography showed that the left vertebral artery (VA) did not originate from the left subclavian artery or aortic arch. A left common carotid artery angiogram showed the presence of the left PPA originating from the left external carotid artery. Mechanical thrombectomy (MT) with contact aspiration using a Penumbra 5MAX ACE 60 aspiration catheter was performed, and successful recanalization was achieved after clot retrieval in the first attempt (thrombolysis in cerebral infarction scale 2b). MRI performed the following day, however, revealed a newly developed large hemorrhagic infarction in the pons, with no improvement in her symptoms (modified Rankin Scale score of 5 at 90 days).

Conclusion

Although MT achieved successful recanalization of the BA via the PPA, her clinical symptoms did not improve, probably because of poor collateral circulation or the long length of the occlusion. In patients with acute vertebro-BA occlusion, if the VA does not originate from the subclavian artery or aortic arch, the presence of a primitive CVA should be considered.

New variant of persistent primitive trigeminal artery associated with duplicated basilar artery: a radiological case report

PURPOSE

This article reports a new variant of the persistent primitive trigeminal artery. This variant does not exist in Salas and Saltzman classifications.

METHODS

We analyzed CTA images of a 39-year-old male patient using RadiAnt. This work had clinical and research purposes.

RESULTS

A persistent primitive trigeminal artery arose from left internal carotid artery termination. Its course was atypical, superior, and lateral to the sella turcica. At its end, it joined a duplicated basilar artery. These morphological features are new compared to Salas and Saltzman's variants.

CONCLUSION

Anatomists, radiologists, and neurosurgeons must know this new variant. Angiographic analysis of this variant will keep the patient safe and perform the surgery. This new variant deserves to be considered in Salas and Saltzman classifications as a new type.

Incidental vascular findings on brain magnetic resonance angiography

Given the ever-increasing utilization of magnetic resonance angiography, incidental vascular findings are increasingly discovered on exams performed for unconnected indications. Some incidental lesions represent pathology and require further intervention and surveillance, such as aneurysm, certain vascular malformations, and arterial stenoses or occlusions. Others are benign or represent normal anatomic variation, and may warrant description, but not further work-up. This review describes the most commonly encountered incidental findings on magnetic resonance angiography, their prevalence, clinical implications, and any available management recommendations.

Case report: Spontaneous carotid-cavernous fistula associated with persistent primitive trigeminal artery aneurysm rupture

Background

The incidence of carotid cavernous fistula (CCF) associated with persistent primitive trigeminal artery (PPTA) aneurysm rupture is extremely rare. We presented a case about a spontaneous CCF secondary to a ruptured PPTA aneurysm, which was successfully embolized with coils and onyx-18 by a trans-arterial approach.

Case presentation

A 55-year-old female suffered a sudden onset of headache, left orbital pain, and pulsatile exophthalmos for a month without any history of trauma. Angiography revealed a left-sided CCF associated with a ruptured PPTA aneurysm, with major drainage to the ipsilateral superior ophthalmic vein. Through a trans-arterial approach, the fistula and ruptured PPTA aneurysm were embolized with coils and onyx-18, while the cavernous sinus and PPTA were well-preserved. However, the preserved PPTA vanished at 4 month follow-up. The patient had no neurological deficit from hospitalization to 1 year follow-up period.

Conclusion

Trans-arterial approach was a reasonable choice for spontaneous CCF associated with ruptured PPTA aneurysm. The requirement for PPTA preservation depended on individual evaluation.

Case Report: Stent Retriever Thrombectomy of Acute Basilar Artery Occlusion via the Type 1 Proatlantal Intersegmental Artery

Stent retriever thrombectomy (SRT) is one of the most effective methods for the recanalization of acute basilar artery occlusion (ABAO). The proatlantal intersegmental artery (PIA) is a rare carotid-vertebrobasilar anastomosis. Recognition of this rare form of anastomosis is particularly important for the rapid establishment of positive blood flow in patients with ABAO. In this case, the patient had a rare, left type 1 PIA. The right vertebral artery (VA) was tenuous and did not enter the cranium. We performed a thrombectomy of the ABAO by inserting a catheter via the type 1 PIA. The complete recanalization of basilar artery (BA) flow was achieved following two stent retractions; however, the patient eventually died of brain stem hemorrhage.

Bilateral type IIpersistent proatlantal intersegmental artery: a rare variant of persistent carotid-vertebrobasilar anastomoses

The persistent proatlantal intersegmental artery is a rare variant of persistent carotid-vertebrobasilar anastomoses, especially their bilateral presence is rarer. We report a case of bilateral typeII persistent proatlantal intersegmental artery. The absence of bilateral vertebral arteries was incidentally noted on neck ultrasound examination. Subsequent time-of-flight MR angiography confirmed this. The bilateral typeIIpersistent proatlantal intersegmental artery arose from the cervical external carotid artery, penetrated the C1 transverse foramen, entered the skull via the foramen magnum, and joined the lower portion of the basilar artery.

Management of intracranial vertebral artery stenosis with ipsilateral vertebral artery hypoplasia and contralateral vertebral artery occlusion via type 2 proatlantal intersegmental artery

BACKGROUND

Proatlantal intersegmental artery (PIA) is a rare primitive carotid-basilar anastomosis. PIA may accompany with ipsilateral or bilateral vertebral arteries (VAs) agenesis. Here, we presented the case with intracranial VA stenosis supplying via PIA and demonstrated how we evaluated and managed.

METHODS

Dual antiplatelet therapy and adequate hydration were given for three weeks for intracranial atherosclerotic disease (ICAD). We arranged magnetic resonance (MR) vessel wall imaging to survey both intracranial VAs. Intracranial right VA stenosis supplying via PIA with ipsilateral VA hypoplasia and contralateral intracranial VA occlusion caused multiple posterior circulation infarcts. We performed angioplasty and intracranial stenting for ICAD at the right VA V4 segment via PIA.

RESULTS

National Institute of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) got improved at discharge and ten months.

CONCLUSIONS

This case is the first report for ICAD management via PIA. A persistent type 2 PIA is essential for supplying posterior circulation.

Embryological development of the human cranio-facial arterial system: a pictorial review

The embryological development of the cerebral vasculature is very complex. Historical and also more recent studies based on human embryos, comparative anatomy and cerebral angiographies allowed us to better understand this vasculature development. The knowledge and understanding of such embryological development are important for physicians interested in neurovascular pathologies. Indeed, all vascular variants and almost all vascular pathologies, such as aneurysms, dolichoectasia, atherosclerosis, and neurovascular conflicts could be explained by an alteration during the embryological life. There are also many variants of these vascular structures present in normal developed adults, which are variably associated with pathological entities. Understanding the process which leads to the development of the normal cerebral arterial system in humans is, therefore, very important to have a better knowledge of the possible clinical and surgical implications of these anomalies. In this paper, we review the embryological development of the cranio-facial arterial vasculature from its beginning at approximately days 21–50 of intrauterine life, with pictures illustrating each developmental phase.

Persistence of a trigeminal artery associated with a posterior meningeal artery aneurysm: case report and literature review

A 59-year-old female presented with severe headache and trouble of consciousness. The CT showed a subarachnoid hemorrhage FISHER IV with a hematoma of the right cerebellum. The angiography discovered a persistent left trigeminal artery associated with an aneurysm of the right posterior meningeal artery. The attempt of embolization failed and the patient suffered cerebral vasospasm and died. The persistence of a trigeminal artery is found in 0.1–0.6% of the population. It is the most frequent embryological carotid-vertebral anastomosis. It appears at the fifth week of development and disappears when the embryo reaches 5–7 mm. This embryological persistence is associated with numerous vascular abnormalities. The literature review showed the presence of those aneurysms in the trigeminal artery itself or the communicating artery. The association that we described is the first to our knowledge. Therefore, this association is particular and interesting to expose.

Treatment of an aberrant inferior temporal artery aneurysm arising off the proximal cavernous segment of the internal carotid artery

We report the clinical details, imaging findings, and management of a 41-year-old female who presented with 6^th cranial nerve palsy from a right proximal cavernous segment internal carotid artery aneurysm arising distal to the branch point of an aberrant inferior temporal artery. Although rare, aberrant branches arising off the proximal ICA may supply the cerebral cortex. Careful evaluation prior to surgical intervention in this setting may reduce the incidence of ischemic complications.

Successful Microvascular Decompression For Trigeminal Neuralgia Secondary to a Persistent Trigeminal Artery

BACKGROUND AND IMPORTANCE

Persistent trigeminal artery (PTA) is a rare but important anatomic variant that contributes to trigeminal neuralgia (TN). Microvascular decompression (MVD) of the responsible vessel(s) away from the trigeminal nerve provides the most complete and durable relief from TN. The role and technique of MVD for TN associated with a PTA has not been fully defined in the literature. Furthermore, assessment of PTA anatomy intraoperatively with a microscope is challenging. We report the first 3-dimensional (3D) microscopic video and first intraoperative endoscopic video of a successful MVD of the trigeminal nerve in a patient who suffered TN from a tortuous, compressive PTA.

CLINICAL PRESENTATION

A 66-yr-old right-handed female presented with right facial pain in V2 and V3 distributions with a clinical picture of TN. Imaging demonstrated trigeminal nerve compression secondary to a PTA and MVD was performed with a 3D operative microscope and an endoscope. The PTA appeared to compress the nerve directly at the trigeminal porus and also had compressive superior cerebellar artery variant branches. The nerve was decompressed at all points of compression with Teflon pledgets along its entire cisternal length. Postoperatively, she is free with trigeminal pain episodes at 4-mo follow-up.

CONCLUSION

In cases of TN associated with a PTA, we recommend decompression along the entire length of the nerve wherever there is compression. Furthermore, we find both the operative microscope and particularly the endoscope useful to assess vascular anatomy intraoperatively.

Absence of the right common carotid artery: a rare case without separate origins of the internal and external carotid arteries

Absence of the common carotid artery (CCA) is a rare anomaly. In the few cases described in the literature, it has been typically associated with separate origins of the internal carotid artery (ICA) and external carotid artery (ECA) Fife (1921), Boyd (1934), Rossiti and Raininko (2001), Cerase et al. (2009), Drazin et al. (2010), Yim et al. (2009), Monaco et al. (2009), Jerius et al. (1995), Dahn et al. (1999), Cakirer et al. (2002), Choi et al. (2015), Bryan et al. (1978), Horowitz et al. (2003), Roberts and Gerald (1978), Rajeshwari (2013), Purkayastha et al. (2006), Maybody et al. (2003), Wood et al. (2011) . To the best of our knowledge, absence of the CCA without separate origins of the ECA and ICA has only been described five times before, one of them in conjunction with a persistent proatlantal intersegmental artery (PIA) Cao et al. (2011) and four with agenesis of the ICA Kobayashi et al. (2013), Kunishio et al. (1987), Chen et al. (2008), Xie et al. (2010) . We present a case of a previously undescribed variation of this rare vascular anomaly.

Persistent Primitive Hypoglossal Artery (PPHA) - A Rare Anomaly with Literature Review

Persistent primitive hypoglossal artery (PPHA) is a rare embryonic carotid vertebrobasilar artery anastomosis. Hypoglossal artery arises from the internal carotid artery (ICA) between the C1 and C2 vertebral levels and traverses through the hypoglossal canal to join the vertebro-basilar system. We present a rare case of an anomalous right sided PPHA as a sole supply to posterior circulation of brain with absent/hypoplastic bilateral vertebral arteries in a two year child who had presented with acute left sided haemiplegia. Three dimensional time of flight magnetic resonance angiography identified an anomalous vessel arising from the right internal carotid artery at the level of axis vertebra and joining the vertebra-basilar arterial system after coursing through the right hypoglossal canal. This anomaly when present may predispose the person to aneurysm formation, ischaemia in the posterior circulation and atherosclerotic disease of the intracranial vessels.

Bilateral Type II Persistent Proatlantal Intersegmental Arteries

A 64-year-old man with treated hypertension presented with acute left arm and leg weakness. A brain magnetic resonance imaging (MRI) and neck magnetic resonance angiography (MRA) were performed. There was restricted diffusion in the right internal capsule posterior limb consistent with an acute lacunar infarct. The MRA demonstrated aplastic bilateral cervical vertebral arteries (V1 and V2 segments). bilaterally, a variant artery arose from the external carotid just above its origin, extended superiorly then medially, and forming the vertebral artery (V3 and V4 segments). bilaterally, the occipital artery arose from the variant artery at the juncture where it turned medially. The right variant artery terminated intracranially in the right posterior inferior cerebellar artery. The left variant artery continued intracranially to supply the basilar. The appearance was consistent with bilateral persistent proatlantal intersegmental arteries (PPIA) type II.

External carotid dissection and external carotid proatlantal intersegmental artery with subclavian steal prompting external carotid and subclavian artery stenting

BACKGROUND AND PURPOSE

The authors describe a case of a proatlantal intersegmental artery seen in the setting of external carotid artery dissection and subclavian steal due to proximal subclavian artery stenosis.

METHODS

An 83-year-old woman presented with left homonymous hemianopsia and a right posterior cerebral artery distribution stroke. She was found to have severe left subclavian artery stenosis proximal to the vertebral artery (VA) and an occluded contralateral VA. Doppler ultrasonography and angiography both showed a dissection of the proximal left external carotid artery. Left common carotid artery angiography also demonstrated a connection between the external carotid and vertebral arteries at the C1 level with anterograde flow into the vertebrobasilar system and retrograde flow toward the vertebral origin, consistent with subclavian steal.

RESULTS

The patient underwent successful stenting of the subclavian and external carotid arteries with resolution of anterograde flow in the left VA.

CONCLUSIONS

This case represents an interesting presentation of both subclavian steal and an external carotid artery to VA anastomosis. Also, the presence of a dissection of the external carotid artery represents a rare finding.

Anatomical features and clinical relevance of a persistent trigeminal artery

Background:

Although persistent trigeminal artery (PTA) is uncommonly identified, knowledge of this structure is essential for clinicians who interpret cranial imaging, perform invasive studies of the cerebral vasculature, and operate this region.

Methods:

A review of the medical literature using standard search engines was performed to locate articles regarding the PTA, with special attention with anatomical descriptions.

Results:

Although anatomical reports of PTA anatomy are very scarce, those were analyzed to describe in detail the current knowledge about its anatomical relationships and variants. Additionally, the embryology, classification, clinical implications, and imaging modalities of this vessel are extensively discussed.

Conclusions:

Through a comprehensive review of isolated reports of the PTA, the clinician can better understand and treat patients with such an anatomical derailment.