Bilateral internal carotid artery agenesis

Rare congenital anomalies of the internal carotid artery: anatomic and radiologic aspects of three cases and review of the literature

PURPOSE

Congenital anomaly of the internal carotid artery (ICA) is a rare entity. It is usually discovered incidentally by color doppler carotid sonography, angiography, computerized tomography (CT), or magnetic resonance imaging of the head and neck region taken for some other reasons. The aim of this study was to detect congenital ICA anomalies, to delineate existing collateral vessels and to find out its incidence.

METHODS

1847 patients' CT angiography images of the head and neck region taken between May 2013 and February 2018 were retrospectively evaluated for ICA anomalies.

RESULTS

We detected three cases (0.16%) with unilateral agenesis of ICA, bilateral agenesis of ICA and bilateral hypoplasia of ICA, respectively. Most patients are asymptomatic because of collateral cerebral circulation supplied by the communicating arteries of the circle of Willis, intercavernous anastomosis, communicating arteries from the external carotid artery, and by persistent embryologic arteries to the carotid artery territory.

CONCLUSION

Recognition of ICA anomalies has important implications during planned carotid or transsphenoidal surgery, in thromboembolic disease, and in the follow-up and detection of associated cerebral aneurysms.

The clinical presentation and collateral pathway development of congenital absence of the internal carotid artery

OBJECTIVE

The objective of this study was to investigate the clinical presentation, risks, and collateral pathway development of the congenital absence of the internal carotid artery (ICA).

METHODS

Sixty-four patients (10 new patients and 54 patients from the relevant literature) were studied. Data on demographic, clinical, and radiologic features were collected, followed by an analysis of the risks associated with ICA agenesis.

RESULTS

There were 31 male and 33 female patients whose ages ranged from 5 months to 75 years, with a mean age of 31.1 years. The range of clinical symptoms recorded included transient ischemic attack (17 patients), subarachnoid hemorrhage (12 patients), developmental delay (13 patients), asymptomatic (8 patients), and other symptoms (15 patients). All 64 patients presented with absence of unilateral or bilateral ICAs, as measured by cervical computed tomography angiography or magnetic resonance angiography. The carotid canal was absent in all patients on computed tomography of the base of the skull, and abnormal development of collateral circulation pathways was observed. Five patients presented with basilar artery dilation on angiography. Aneurysms were observed in the angiography results from 16 patients. Ten patients presented with variations in the ophthalmic artery origin (the ophthalmic artery originated from the ipsilateral middle meningeal artery in six patients and from the ipsilateral middle cerebral artery in four patients).

CONCLUSIONS

From analysis of our 10 cases of ICA agenesis and our review of the relevant literature, we conclude that young patients with ICA agenesis may present with developmental delay, subarachnoid hemorrhage, or other developmental abnormalities, whereas older patients most commonly present with transient neurologic events. Complications of carotid agenesis are related to specific anatomic subtypes and the resulting collateral circulation development.

Congenital absence of the bilateral internal carotid artery: a review of the associated (ab)normalities from a newborn status to the eighth decade of life

PURPOSE

Due to the fact that the internal carotid artery (ICA) is responsible for nourishing two thirds of the brain volume, our aim was to inspect the morphofunctional consequences of the bilateral lack of this artery.

METHODS

In order to examine this condition, we referred to both the library archive of our Faculty of Medicine and electronic databases of anatomical and clinical reports that included the following keywords: "absence," "aplasia," or "agenesis" in combination with "internal carotid artery," "common carotid artery," or only "carotid artery."

RESULT

We found 60 recorded cases of the bilateral ICA absence in the subjects of newborn status to the eighth decade of life, which had been discovered in 20 countries. The following ten parameters were described: the embryological base, terminology, history, incidence, general data, differential diagnosis, collateral circulation, the associated vascular aplasia and/or other variants, pathophysiology, and the importance in praxis.

CONCLUSION

This review noted all the cases of the bilateral ICA aplasia published for the past 104 years. Although there were 11.6% of cases of the associated cerebral aneurysms and 1-4 cases of 16 other diseases, approximately one quarter of the cases was without any pathology.

Bilateral internal carotid artery agenesis: a case report

Agenesis of the internal carotid artery (ICA) is defined as a congenital absence of the carotid canal and occurs in less than 0.01% of the population. This anomaly is usually diagnosed as an incidental finding or after a cerebrovascular event. We present the case of a 36-year-old woman, with bilateral agenesis of the ICA who had suffered a subarachnoid hemorrhage due to ruptured aneurysm of the basilar artery. Therefore, agenesis of the ICA is a condition that, although rare, should be considered since there is a risk of coexistence with other life-threatening conditions such as aneurysms.

Bilateral agenesis of the internal carotid artery associated with basilar artery aneurysm treated via the endovascular route. A case report

Bilateral agenesis of the internal carotid artery is a rare anomaly of embryonic development frequently associated with intracranial aneurysm. We describe a case involving an aneurysm that burst in the third middle of the basilar artery and exhibited a bilateral agenesis of the internal carotid artery. The aneurysm was treated via an endovascular route using detachable coils.

Bilateral agenesis of the internal carotid artery: case report and approach to management

We present the case of a 13-year-old boy who presented with two episodes of acute onset severe headache. Initial investigation with computerised tomography revealed no apparent abnormality. Magnetic resonance imaging and magnetic resonance angiography revealed that this boy had absence of both internal carotid arteries bilaterally. Absence of the internal carotid arteries is an uncommon condition, but does occur with unilateral absence being more common than bilateral absence. The condition is usually diagnosed in adulthood but may be diagnosed incidentally in childhood. When diagnosed in childhood, the main aim of management is to prevent the development of cerebrovascular accidents.

MRI of bilateral internal carotid artery agenesis

Bilateral internal carotid artery (ICA) agenesis is rare. A patient presented with symptoms of a transient ischaemic attack. Magnetic resonance imaging with magnetic resonance angiography showed multiple foci of chronic cerebral ischaemic change and bilaterally absent ICA. Cerebral supply was derived from the posterior circulation. Differentiation has to be made between congenital agenesis/hypoplasia and acquired ICA occlusion. Computed tomography through the skull base showed the absence of the carotid canals bilaterally confirming congenital ICA agenesis.

Congenital absence or hypoplasia of the carotid artery: radioclinical issues

PURPOSE

Congenital anomaly of the carotid artery is a rare abnormality. It is usually discovered incidentally by color Doppler carotid sonography, angiography, computed tomography (CT), or magnetic resonance imaging (MRI) of the head and neck taken for some other reason. Most patients are not symptomatic because of sufficient cerebral circulation supplied to the defective area by the communicating arteries of the circle of Willis, intercavernous anastomosis, communicating arteries from external carotid artery, and by persistent embryologic arteries to the carotid artery territory. However, sometimes, this anatomic variation may eventually lead to some clinical signs and symptoms in particular circumstances in the head and neck of which surgeons are unaware. A retrospective study was designed to emphasize the characteristic radiologic and clinical picture in patients with the congenital absence (agenesis and aplasia) or hypoplasia of the carotid artery, to delineate the associated abnormalities and existing collateral vessels, and to find out its incidence.

MATERIAL AND METHODS

Five thousand one hundred cerebral MRI and/or catheter angiograms performed between February 1988 and March 2002 were reviewed for carotid artery abnormality.

RESULTS

Seven patients with congenital absence or hypoplasia (4 of these patients were presented with hypoplasia of internal carotid artery [ICA], 3 with absence of ICA) of ICA were identified (0.13%). The radiologic and clinical study of 5 patients with unilateral (3 of these patients were presented with hypoplasia and 2 with absence of ICA) and 2 patients with bilateral (1 was presented with absence of ICA, whereas the other was hypoplasia) congenital abnormality with absence or hypoplasia of ICA demonstrate that those patients are usually asymptomatic and they are diagnosed incidentally.

CONCLUSION

It has been concluded that the combined use of magnetic resonance angiography and CT scanning of the skull base may disclose small but patent ICA. Collateral vessels seem to be usual in such cases, but they may be prominent in cases of acquired vascular occlusion, or increased hemodynamic pressure in dysplastic changes in collateral arteries are known causes of aneurysms. The main vascular supply for the brain in patients with congenitally small (hypoplasia) or absent (agenesis or aplasia) ICA is the vertebrobasilar system in bilateral cases. However, contralateral carotid vessel is the dominant arterial supply for unilateral cases, which has to be borne in mind in surgical interventions to the involved side.

Bilateral congenital absence of the internal carotid artery

Bilateral congenital absence of the internal carotid artery was incidentally found in an 11-year-old boy. Magnetic resonance imaging showed a normal-appearing brain that was entirely supplied by the vertebrobasilar system, and CT confirmed the absence of the bony carotid canals. Although most reported patients with agenesis of both internal carotid arteries presented with cerebrovascular lesions, this case demonstrates that this rare malformation may be asymptomatic.

Congenital absence of the internal carotid artery: case reports and review of the collateral circulation

Absence of the internal carotid artery (ICA) is a rare congenital anomaly. The embryology of the ICA and the common collateral pathways associated with its congenital absence are reviewed, with four new cases provided for illustration. While collateral blood flow may allow these patients to remain asymptomatic, two of our patients presented with transient ischemic attacks. Recognition of this anomaly has important implications during planned carotid or transsphenoidal surgery, in thromboembolic disease, and in the surveillance and detection of associated cerebral aneurysms.

Agenesis of the internal carotid artery: color Doppler, CT, and MR angiography findings

Agenesis of the internal carotid artery (ICA) is a rare finding that can lead to the false diagnosis of an ICA occlusion. We present the case of a young woman with agenesis of the left ICA. Diagnosis was made noninvasively by color Doppler imaging (CDI) in combination with high-resolution CT of the base of the skull. Magnetic resonance angiography confirmed the diagnosis. CDI in combination with CT of the base of the skull allows the diagnosis of ICA agenesis without the use of invasive procedures.