Anomalous origin of the ophthalmic artery from the anterior cerebral artery

Morphometric study regarding ophthalmic and internal carotid arteries utilizing computed tomography angiography

The aim of the present study was to accurately measure the diameter of the ophthalmic artery (OA) and investigate whether bilateral variations in diameter can be recorded in relation to patient age and sex. A retrospective study including 80 computed tomography angiographic (CTA) examinations and a total of 160 arteries was conducted to demonstrate the morphometric aspects of the OAs analyzed bilaterally by CTA examinations, while considering the references of the internal carotid artery (ICA) caliber. Precise measurements performed on the OA and the ICA below and above the ophthalmic emergence revealed an OA diameter of 1.38±0.24 mm and a narrowing of the ICA between the origin of the OA of 1.5±0.25 mm. Variations in the OA and the ICA calibers were studied in subjects with normal cervical vasculature on CTA. After a thorough statistical study, variations in OA and ICA caliber on each side were identified, between both sex and age-related groups, revealing morphometric parameters of the OA in relation to the ICA.

Embryology and anatomical variations of the ophthalmic artery

PURPOSE

The ophthalmic artery (OA) has one of the most complex anatomy and the most fascinating embryological development.

METHODS

The complexity of the embryologic development of the OA resides in the implication of three different embryological systems: the carotid system, the stapedial system, and the ventral pharyngeal system.

RESULTS

This explains very well the numerous variations in origin of the OA and the importance of vascular anastomoses developed with branches of the external carotid artery and with the middle meningeal artery.

CONCLUSION

In this review, authors propose a comprehensive description of different hypotheses on the embryologic development of the OA and, in a second part, explain all anatomical variations and clinical implications of this artery.

Unusual ophthalmic artery origin: Implications for intraarterial chemotherapy of retinoblastoma

We report two pediatric retinoblastoma patients with unusual ophthalmic artery (OA) origins who were referred to our interventional neuroradiology department for intraarterial chemotherapy. The first patient had double OAs arising from the ipsilateral internal carotid artery and a central retinal artery (CRA) arising from the more cranially located artery, whereas the second patient had an OA originating from the A1 segment of the ipsilateral anterior cerebral artery. In both cases the CRA arose from the artery entering the orbit through the optic foramen. Both patients tolerated the procedures well. To the best of our knowledge, our retinoblastoma patients with unusual OA origins are the first in the literature in which detailed knowledge of the orbital vasculature and especially CRA origin carried immediate clinical implications, altering access strategies. These variations were proved both by flat-panel detector computed tomography findings and superselective injections of OAs with unusual origins. Our results show that in patients with retinoblastoma, a detailed angiographic work-up may be necessary to evaluate the orbital vasculature and possible abnormal origin of the OA. Recognition of possible variations of OA origin and its branching patterns is of the utmost importance for successful treatment and avoidance of adverse events among retinoblastoma patients.

Ophthalmic Arteries Arising from the Bilateral Anterior Cerebral Arteries Diagnosed by Three-Dimensional Time-of-Flight Magnetic Resonance Angiography

BACKGROUND

The ophthalmic artery (OA) is a very important branch of the supraclinoid segment of the internal carotid artery. Origination of the OA from the anterior cerebral artery is an extremely rare condition. Being unaware of the origin anomalies of OAs can lead to unfavorable results, especially in cases in which craniofacial surgery or cerebral therapeutic angiography is planned.

CASE DESCRIPTION

An anomalous origin of the ipsilateral OAs from the A1 segments of the bilateral anterior cerebral arteries was detected by three-dimensional time-of-flight magnetic resonance angiography.

CONCLUSIONS

Anomalous origin of the OA from the anterior cerebral artery may be explained by a failure in the caudal migration of the ventral OA. Because of high soft tissue resolution and absence of radiation, three-dimensional time-of-flight magnetic resonance angiography is preferred for detection of orbital and cerebral vascular anomalies.

Anomalous Origins of Ophthalmic Arteries on Three-Dimensional Time-of-Flight Magnetic Resonance Angiography and Their Clinical Importance

AIM

The purpose of this paper was to evaluate rare cases of anomalous origins of the ophthalmic artery (OA) according to magnetic resonance angiography (MRA) findings.

METHODS

This retrospective study included 80 patients diagnosed with anomalous OA origins between March 2015 and July 2018 from a sample of 16,024 patients. The patients included 47 females and 33 males with a mean age of 38.16 years (range 18-62 years). Three-dimensional time-of-flight (3D-TOF) MRA was performed for all patients.

RESULTS

Eighty (0.5%) patients had anomalous OA origins. The most common type of OA origin anomaly was the right OA originating from the middle meningeal artery (0.17%). Twelve (0.07%) patients had OAs with an extradural origin.

CONCLUSIONS

Anomalous origins of the OA are rare. 3D-TOF MRA is a noninvasive imaging method that can be applied for the diagnosis of OA anomalies. Some OA variations can have a protective effect against ocular complications in vaso-occlusive events. Therefore, it is critical to know the variant anatomy of OAs.

The Three-Dimensional Computed Tomography Anatomic Features of Internal Carotid Artery-Ophthalmic Artery

OBJECTIVE

This research aimed at exploring the measurement of anatomic parameters of internal carotid artery-ophthalmic artery (ICA-OA) and the clinical significance with 3-dimensional (3D) separating, fusing, opacifying, false-coloring, and volume rendering (SFOF-VR) technique.

METHODS

A total of 109 patients with no significant lesions in ICA-OA were randomly selected, including 56 males and 53 females, who were divided into 3 groups: young age group (18-40 years, n = 36), middle age group (41-60 years, n = 40) and old age group (>60 years, n = 33). The 3D images were constructed by AW 4.6 workstation, and the anatomic parameters were measured. The SFOF-VR technique explicitly displayed ICA, OA, and their concomitant relationship with ophthalmic nerves (ONs) and adjacent structures. The study protocol was approved by the Medical Ethical Committee of Shaanxi Provincial People's Hospital and all patients have signed consent forms.

RESULTS

The diameters of initial segment of left and right ophthalmic ICA (ICA-C6) were 3.58 ± 0.51 mm and 3.58 ± 0.43 mm, respectively; the diameters of the left and right OA were 1.16 ± 0.16 mm and 1.15 ± 0.19 mm, respectively; the lengths of left and right ICA-C6 were 10.43 ± 2.08 mm and 10.01 ± 2.32 mm, respectively. There were statistically significant differences between bilateral ICA-C6 lengths, right ICA-C6 diameter, right OA diameter, and OA-ON space between male and female.

CONCLUSION

The SFOF-VR technique can distinctly present the structures of ICA-OA and adjacent tissues, providing valuable information for surgical operation. The 3D computed tomography data about ICA-OA can enrich references for basic and clinical researches.

Functional Vascular Anatomy of the Brain

Functional vascular anatomy is the study of anatomy in its relation to the function that figures out the normal and pathological vascularization of the brain and spinal cord. The mechanism of anatomical variations (e.g. fenestration of the basilar artery, persistent primitive trigeminal artery, and aberrant subclavian artery) can be explained according to the embryological development of the cardiovascular system. The most developmental process is common among the species of the vertebrates from the fish to the mammalian in the early phase of embryo. Thus, it is possible to deduce the reasons of vascular variants in terms of phylogeny. Such an embryological parallelism like the comparative anatomy provides the new insights into the nature of our vascular system. In addition, learning more about the hemodynamic consequence may help to realize the underlying physiopathology of cerebral arterial remodeling and stroke in patients with these vascular variants. This perception may facilitate better understanding of the vascular pathologies and lead to the appropriate decision making not only in the diagnostic work, but also in the interventional procedures. The aim of this study is to introduce the meanings of functional anatomy in the clinical application of vascular diseases and anomalous of the central nervous system.

An update on the variations of the orbital blood supply and hemodynamic

Purpose

Several variations of the arterial blood supply of the orbit have been reported over the years. This review is aimed to provide an update focusing on three important issues: (a) variations of the ophthalmic artery origin; (b) contribution of the external carotid artery to the orbital blood supply; (c) orbital hemodynamic.

Methods

A PubMed and Google search was carried out with the following keywords: ophthalmic artery origin, ophthalmic artery anastomoses and ophthalmic artery anatomy.

Results

The site of origin of the ophthalmic artery displays a limited number of variations. However they are important as they are also associated with course variations. Anastomoses between the ophthalmic artery and the external carotid artery are numerous and many of them can acquire clinical relevance. Records on their anatomic frequency are limited. Orbital hemodynamic variations are a poorly studied subject. Recent investigations in children have unveiled unexpected variability and instability in the way the blood flows through the orbit.

Conclusions

The orbit shows several possible arterial variations. Some of them have a profound influence on its hemodynamic at least in children. More studies are required to ascertain if the hemodynamic variability observed in children can be pinpointed also in adults.

Anatomy of the Ophthalmic Artery: Embryological Consideration

There are considerable variations in the anatomy of the human ophthalmic artery (OphA), such as anomalous origins of the OphA and anastomoses between the OphA and the adjacent arteries. These anatomical variations seem to attribute to complex embryology of the OphA. In human embryos and fetuses, primitive dorsal and ventral ophthalmic arteries (PDOphA and PVOphA) form the ocular branches, and the supraorbital division of the stapedial artery forms the orbital branches of the OphA, and then numerous anastomoses between the internal carotid artery (ICA) and the external carotid artery (ECA) systems emerge in connection with the OphA. These developmental processes can produce anatomical variations of the OphA, and we should notice these variations for neurosurgical and neurointerventional procedures.

Ophthalmic artery originating from the anterior cerebral artery: anatomo-radiological study, histological analysis, and literature review

The ophthalmic artery has an anomalous origin in 2-3 % of cases and rarely arises from the anterior cerebral artery. Herein, we provide the first anatomical, radiological, and histological description of such an anomalous origin, together with a literature review. During the anatomical dissection of an 81-year-old Caucasian male, the absence of the right ophthalmic artery in its usual location was evident from an endonasal transsphenoidal perspective. The specimen was then studied in detail, through multiple dissections, corrosion casting, high-resolution CT, and histological analysis. The English literature on anomalous origins of the ophthalmic artery was reviewed, together with reported associated pathologies. Anatomo-radiological analysis documented that the right ophthalmic artery arose from the inferior surface of A1 tract of the anterior cerebral artery (A1) and passed over the optic nerve in its subarachnoid tract. A meningo-ophthalmic artery was evident on the same side and reached the orbit through the superior orbital fissure. Histological examination of both internal carotid artery (ICA) walls documented a significantly decreased thickness of the tunica media and adventitia on the side of the anomalous ophthalmic artery, with a significantly different content of collagen types I and III. The literature review documented an association of aneurysms and anomalous ophthalmic arteries. To the best of our knowledge, this is the first anatomical report that includes a radiological and arterial wall analysis of a persistent ventral ophthalmic artery. The latter provides histological data that support the clinical evidence of a higher association of aneurysms with anomalous origins of the ophthalmic artery.

Anatomy of the Ophthalmic Artery: A Review concerning Its Modern Surgical and Clinical Applications

Anatomy of ophthalmic artery has been thoroughly studied and reviewed in many anatomical and surgical textbooks and papers. Issues of interest are its intracranial and extracranial course, its branches, its importance for vision, and its interaction with various intracranial pathologies. Improvement of our understanding about pathophysiology of certain diseases like aneurysm formation, central retinal artery occlusion, and retinoblastoma and also invention of new therapeutic modalities like superselective catheterization, intra-arterial fibrinolysis, and intra-arterial chemotherapy necessitate a reappraisal of its anatomy from a clinical point of view. The aim of this review is to examine clinical anatomy of ophthalmic artery and correlate it with new diagnostic and therapeutic applications.

Ventral and Dorsal Persistent Primitive Ophthalmic Arteries

BACKGROUND

Before the development of the adult ophthalmic artery (OA), the primitive maxillary artery (MA), the primitive dorsal OA, and the primitive ventral OA contribute to the vascularization of early ocular structures, whereas the primitive olfactory artery (OlfA) forms in the vicinity of the optic vesicle. These vessels are involved in several OA origin variants.

OBJECTIVE

To clarify the developmental history of the OA, emphasizing in particular the criteria used to define persistent primitive OAs.

METHODS

Eight rare variants relevant to the discussion of aberrant OA origins are presented.

RESULTS

Five abnormal anatomic configurations are described including (1) OAs branching from the cavernous internal carotid artery (ICA) involving a persistent primitive MA, (2) OAs originating from the distal supraclinoid ICA involving persistent primitive ventral or dorsal OAs, (3) an OA originating from the anterior cerebral artery (ACA) involving a persistent primitive OlfA, (4) a persistent primitive OlfA, and (5) infraoptic ACAs involving the persistent primitive MA, OlfA, and OA.

CONCLUSION

Discrepancies regarding the identification of persistent primitive OAs appear to result from a misinterpretation of the literature. Notably, an OA arising from the cavernous segment of the ICA derives from a primitive MA, whereas an OA arising from the ACA represents the partial persistence of a primitive OlfA; neither corresponds to a persistent primitive OA. Two new observations of this latter variant, which is exceptional, are presented.

Different ophthalmic artery origins: Embryology and clinical significance

This retrospective study gives a summary of ophthalmic artery (OA) variations to serve as guidelines for surgical interventionists and trainees. Pubmed and Medline searches were conducted. The OA usually arises intradurally (superomedial, anteromedial, or rarely superolateral) from the internal carotid artery (ICA). Rare extradural origin (primitive dorsal OA) (PDOA) remnant and extremely rare interdural origin (primitive ventral OA) (PVOA) remnant are of significance when sectioning the dural ring. Rarely, a persistent PDOA with ICA origin, or a PDOA remnant with inferolateral trunk origin, enters the orbit via the superior orbital fissure (SOF) for sole or partial orbital supply. Extremely rare, the PDOA and PVOA persist and form double OAs that arise from the ICA and run via the SOF and optic foramen. Occasionally, the OA arises from the middle meningeal artery (MMA), when both the PDOA and VDOA regress and enter the orbit via the SOF. Sole orbital supply via the external carotid artery (ECA), i.e. meningo-ophthalmic artery and/or MMA branches, or dual OAs (ECA and ICA origins) may occur. Other rare OA origins include anterior or posterior communicating artery; anterior or middle cerebral artery; basilar artery; posterior inferior cerebellar artery; and the carotid bifurcation. Primitive arteries (persistent or remnant), and/or abnormal anastomoses play pivotal roles in manifestations of OA variations. Of clinical importance are orbital collateral routes and dangerous extracranial-intracranial anastomoses. Awareness of OA origins and collateral routes is imperative for transarterial embolizations or infusion chemotherapy in the ECA territory to prevent visual complications.