Vascular anomalies and the risk of multiple aneurysms development and bleeding

Rare neurovascular variants that you probably have not seen before

BACKGROUND

Recognition of neurovascular variants is crucial for safe endovascular and neurosurgical interventions. We aim to review and highlight various uncommon neurovascular variants and anomalies with a discussion of their relevant embryology and pathology.

METHODS

A retrospective review of a prospectively maintained neurovascular database was performed to identify uncommon neurovascular variants and anomalies. A pictorial review of these neurovascular findings is provided along with relevant embryological development, clinical significance, and potential pathological associations.

RESULTS

A pictorial review of selected neurovascular variants and anomalies is presented. These entities, divided between intra- and extra-cranial findings, include infra-optic origin of the anterior cerebral artery, meningo-ophtalmic artery, duplicated posterior cerebral artery, duplicate middle cerebral artery (MCA), MCA fenestration, twig-like MCA, pure arterial malformation, corkscrew basilar artery, persistent hypoglossal artery, persistent trigeminal artery and its variants, direct branches from the common carotid and cervical internal carotid arteries (ICA) (ascending pharyngeal artery from the ICA, thyroidal arteries from the CCA/brachiocephalic, arteria thyroidea ima), and extra-cranial carotid fenestration. The angiographic findings of these entities are presented with relevant 3D reconstruction and multimodal cross-sectional imaging correlation when available.

CONCLUSIONS

This pictorial review highlights uncommon neurovascular variants and anomalies that neuroradiologists, interventionalists, and neurosurgeons should be aware of for accurate diagnosis and safe interventions.

Internal carotid artery-persistent primitive anterior choroidal artery aneurysms: report of two cases and literature review

PURPOSE

Persistent primitive anterior choroidal artery (PPAChA) is a rare vascular anomaly. The clinical course of internal carotid artery (ICA)-PPAChA aneurysms has not been well described.

CASE REPORTS

We report two patients with an ICA-PPChA aneurysm and summarize previously reported cases.

RESULTS

Including our two, a total of 10 patients with an ICA-PPAChA aneurysm have been reported. Data were not described for one. Among the remaining nine, five patients (56%) experienced aneurysmal rupture. Five patients underwent surgical clipping and four underwent endovascular coiling. The procedure was completed in all but one patient who had a tiny branch artery adherent to the aneurysm; this patient was converted from clipping to aneurysm coating with a cotton sheet. Among the other eight patients, one who underwent coiling experienced an internal capsule infarction. The remaining seven had a satisfactory postoperative course; however, an asymptomatic occlusion of the PPAChA at its origin was noted on postoperative angiography in one.

CONCLUSION

PPChA is associated with a high incidence of aneurysm formation and rupture. During treatment of ICA-PPAChA aneurysms, obstruction of the PPAChA and any surrounding perforating arteries should be avoided to prevent ischemic stroke.

Quantitative Evaluation of Hemodynamic Changes After Multiple Intracranial Aneurysms Occlusion Using Computational Fluid Dynamics

OBJECTIVE

Multiple intracranial aneurysms (MIA) are prevalent. This study conducted hemodynamic calculations on MIA to analyze the effects of occlusion of the internal carotid artery (ICA) and middle cerebral artery (MCA) aneurysms on the hemodynamics of other arteries, as well as the issue of the treatment order for these aneurysms.

METHODS

The models of 9 patients with MIA were selected for the study. A computational fluid dynamics model combining 1-dimension and 3-dimension was used to obtain the vascular flow pattern and wall pressure.

RESULTS

There was increased pressure at the MCA and anterior cerebral artery (ACA) after occlusion of the aneurysm at the ICA. However, the pressure at the ICA has hardly changed after the aneurysm occlusion at the MCA. Occlusion of the aneurysm of different sizes at the MCA had almost no impact on the pressure at the ICA and ACA. For small aneurysm, the pressure of the ACA and MCA increases with decreasing size of the aneurysm at the ICA. After occlusion of a large aneurysm at the ICA, the impact on the pressure of the ACA and MCA is almost the same as after occlusion of a medium-sized aneurysm.

CONCLUSIONS

If the treatment order of ICA and MCA aneurysms cannot be determined based on patient factors and aneurysm characteristics, the MCA aneurysm should be treated as a priority.

Reference Values of Cerebral Artery Diameters of the Anterior Circulation by Digital Subtraction Angiography: A Retrospective Study

A threshold-based classification of cerebral vasospasm needs reference values for intracranial vessel diameters on digital subtraction angiography (DSA). We aimed to generate adjusted reference values for this purpose by retrospectively analyzing angiograms and potential influencing factors on vessel diameters. Angiograms of the anterior circulation were evaluated in 278 patients aged 18−81 years. The vessel diameters of 453 angiograms (175 bilateral) were gathered from nine defined measuring sites. The effect sizes of physical characteristics (i.e., body weight and height, body mass index, gender, age, and cranial side) and anatomical variations were calculated with MANOVA. Segments bearing aneurysms were excluded for the calculation of reference values. Adjusted vessel diameters were calculated via linear regression analysis of the vessel diameter data. Vessel diameters increased with age and body height. Male and right-sided vessels were larger in diameter. Of the anatomical variations, only the hypoplastic/aplastic A1 segment had a significant influence (p < 0.05) on values of the anterior cerebral artery and the internal carotid artery with a small effect size (|ω2| > 0.01) being excluded from the reference values. We provide gender-, age-, and side-adjusted reference values and nomograms of arterial vessel diameters in the anterior circulation.

Recurrent vertebrobasilar strokes and transient-ischemic attacks with challenging workup: Case report

Detecting the stroke etiology in young patients can be challenging. Among others, determining causality between ischemic stroke and patent foramen ovale (PFO) remains a complicated task for stroke neurologists, given the relatively high prevalence of PFOs. Thorough diagnostic workup to identify incidental vascular risk factors and rare embolic sources is crucial to avoid premature PFO closure suggesting successful secondary stroke prevention. In this paper, we report on a 38-year-old patient with recurrent vertebrobasilar territory, especially right posterior inferior cerebellar artery (PICA) territory strokes. After the initial suspicion of a left vertebral artery (VA) dissection was not confirmed by ultrasound and magnetic resonance imaging (MRI) and other major risk factors were excluded, a PFO was detected and closed. Successful PFO closure was confirmed by transesophageal echocardiography, yet recurrent transient-ischemic attacks and vertebrobasilar strokes, especially during nighttime and in the early morning, occurred despite various antiplatelet and antithrombotic regimes and a persistent right-to-left shunt was detected by bubble transcranial Doppler. Finally, MRI after another vertebrobasilar infarction detected a transient left VA occlusion that finally led to the diagnosis of a left VA pseudoaneurysm from an incident emboligenic dissection in the atlas segment. This pseudoaneurysm together with an anatomical variant of the right PICA originating with the right anterior inferior cerebellar artery from the basilar artery finally explained the recurrent ischemic events of the patient. After successful treatment with coil occlusion, the patient suffered no further stroke and recovered completely. In summary, stroke in the young remains a diagnostic challenge. The incidental finding of a PFO should not deter from thorough stroke workup and the follow-up of these patients including PFO closure verification should be performed under the guidance of vascular neurologists.

Distal anterior cerebral artery aneurysm with bilateral fetal posterior cerebral arteries and trifurcation of anterior cerebral artery

Developmental vascular anomalies of brain are non-modifiable risk factors for the development of aneurysms and are prone for rupture. We report one such association in a 44-year-old gentleman who succumbed to subarachnoid hemorrhage (SAH) secondary to ruptured distal anterior cerebral artery aneurysm associated with vascular anomalies in the anterior and posterior circulation that included trifurcation of anterior cerebral artery and bilateral fetal posterior cerebral arteries. We identified multiple anomalies in circle of Willis that could have contributed to the formation of aneurysm and early rupture. Knowledge of these variations is essential to plan early and optimum management with close follow-up.

Challenges in the Management of a Ruptured Bihemispheric Posterior Inferior Cerebellar Artery Aneurysm

BACKGROUND

Bihemispheric posterior inferior cerebellar artery (PICA) is a rare anatomic variant wherein a single PICA supplies both cerebellar hemispheres. Inasmuch as it is the only PICA, treatment of aneurysms arising from this anatomic variant is more complex. We present a case of a ruptured bihemispheric PICA aneurysm and the challenges encountered in its management.

CASE DESCRIPTION

A 54-year-old man presented with giddiness and nausea. Otherwise, he was neurologically intact. Computed tomography of the brain showed a right cerebellar hematoma and intraventricular hemorrhage. Cerebral angiography revealed a dissecting aneurysm in the retromedullary segment of a right bihemispheric PICA with a prominent saccular component. Initially, the patient refused to undergo any invasive treatment. However, when a follow-up angiogram showed an increase in the size of the aneurysm sac, he consented to treatment. Although parent vessel occlusion (PVO) was the clinical recommendation, in view of the patient's apprehensions, only the saccular component of the aneurysm was coil embolized without sacrifice of the parent vessel. Fifteen days after the coiling, there was a rebleed from this dissecting aneurysm, which was treated with PVO followed by suboccipital craniectomy. The patient made a reasonable recovery, and his modified Rankin score was 1 at his 6-month follow-up visit.

CONCLUSIONS

In dissecting aneurysms of a bihemispheric PICA, isolated endosaccular occlusion provides uncertain protection from a rebleed, whereas a more reliable treatment with PVO carries an unpredictable risk of ischemic complications. The risks of a PVO may be rationalized as a life-saving measure; however, the subsequent threshold for posterior fossa decompression should be low.

Posterior inferior cerebellar artery with an extradural origin from the V3 segment: higher incidence on the nondominant vertebral artery

OBJECTIVE The posterior inferior cerebellar artery (PICA) and the vertebral artery (VA) often exhibit anatomical variations at the craniovertebral junction (CVJ). An example of this is the PICA originating extradurally from the V₃ segment of the VA. To date, some cadaveric investigations have been reported, but the incidence and relationship of this variation to the VA and the atlas as observed on clinical imaging have not been discussed. This study evaluated the prevalence of PICAs originating from the V₃ on CT scanning. Other variations of the atlas and VA were also analyzed. METHODS CT images from a series of 153 patients who underwent 3D CT angiography (CTA) were analyzed, and variations of the PICA, VA, and atlas were investigated. RESULTS A total of 142 patients (284 sides) were analyzed; 11 patients (7.2%) were excluded due to poor image quality. The most common VA variation was the PICA originating from V₃ (9.5% of 284 sides), which was more frequently observed on the nondominant VA than the dominant VA (22.5% vs 6.25%, p = 0.0005). A VA with a PICA end was identified in 4 sides (1.4%), which is the same incidence as observed in the persistent first intersegmental VA (1.4%). VA fenestration was only found in 1 side (0.35%). Regarding the atlas, ponticulus posticus was observed in 24 sides (8.5%). There was no relationship between the incidence of ponticulus posticus and the variations of the VA. CONCLUSIONS A PICA originating from V₃ was the most common VA variation at the CVJ and was more common on the nondominant VA. Three-dimensional CTA is useful for the evaluation of this variance. Surgeons should be mindful of this variation during operations.

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.

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.

Left type I proatlantal artery with bilateral aberrant vertebral arteries and a ruptured aneurysm: a case report and review of the literature

Persistent proatlantal artery is one rare kind of persistent primitive anastomoses between carotid and basilar vascular system. This case firstly introduces a type I proatlantal artery with complex vascular anomalies of bilateral vertebral arteries and a ruptured aneurysm, which is extremely uncommon. A 43-year-old female was hospitalised for SAH and ventricular hematocele. The subsequent digital subtraction angiography and computed tomography angiography revealed a type I proatlantal artery which arises from left internal carotid artery, associating with a hypoplastic right vertebral artery, an aplastic left vertebral artery and a ruptured left posterior inferior cerebellar artery aneurysm. An interventional procedure was taken later. The present case raises awareness on the incidence of persistent primitive anastomoses which combined other complex vascular anomalies before surgical or interventional procedures, especially in view of unique blood supply to posterior circulation from the primitive vessel.

A case of aneurysm on a persistent hypoglossal artery treated by endovascular coiling

SUMMARY

We describe a 22-year-old woman admitted to hospital in emergency with nuchal headache and vomiting. CT scan disclosed subarachnoid hemorrhage. Digital subtraction angiography with three-dimensional rotational acquisitions showed a ruptured aneurysm of a right persistent primitive hypoglossal artery as the cause of symptoms and hemorrhage. The patient was successfully treated with endovascular coiling of the aneurysm. This is the second literature report describing endovascular treatment in this unusual condition.

Intradural saccular aneurysms treated by Guglielmi detachable bare coils at a single institution between 1993 and 2005: clinical long-term follow-up for a total of 1810 patient-years in relation to morphological treatment results

BACKGROUND AND PURPOSE

The aim of this study was to analyze the clinical results of Guglielmi detachable bare coil (GDC) embolization of intradural saccular aneurysms (AAs) at a single center and to relate the morphological results at various time points to the clinical situation.

METHODS

All intradural saccular AAs treated with GDCs between 1993 and April 2005 were prospectively entered into a database completed by retrospective analysis of charts and images and a long-term clinical outcome questionnaire. In 413 consecutive patients, there were 466 treated AAs, of which 68.7% were ruptured and 31.1% were unruptured.

RESULTS

The periprocedural thromboembolic event rate, retreatment procedures included, was 5.4%, causing permanent neurologic deficits in 2.2% of patients. One patient (0.2%) bled during a mean+/-SD clinical follow-up of 64.3+/-39.9 months (93 AAs were followed up for >8 years and 45 AAs were followed up for >10 years) for a total of 1810 patient-years. The modified Rankin Scale score was 0 in 54.7%, 1 in 21.0%, 2 in 12.1%, 3 in 7.1%, 4 in 2.1%, 5 in 0.3%, and 6 (death from unrelated causes) in 2.7% of patients. If an aneurysm, with or without a remnant, was unchanged for 12 months, then the risk for future morphological loss was 4.8%, whereas if an aneurysm showed a morphological loss during the earlier 12-month interval, the risk for additional late loss was 38.3% (P<0.001, odds ratio=12.4).

CONCLUSIONS

Embolization of saccular AAs entails a prolonged management period. A stable angiographic result during a 12-month interval predicts a low risk for morphological deterioration. This regimen, aiming for a stable angiographic result rather than complete aneurysm occlusion, gives a low rebleed rate and excellent clinical long-term results.

"Duplicated" or "multiple" cervical internal carotid and vertebral arteries from fenestration, duplication and vasa vasorum to segmental rete

SUMMARY

The appearance of multiple cervical arteries may be due to a variety of anatomic situations. Arterial fenestrations and duplications have different anatomic origins, with distinct appearances on angiography. They are associated with incomplete segmental development. The vasa vasorum of the internal carotid artery are rarely seen unless enlarged in pathological situations. They represent a peculiar segmental, in-situ, collateral circulation. Retes, on the other hand, correspond to a more complex reconstitution of an early segmental regression. Careful analysis of each of these features is required to choose the best appropriate terminology. The purpose of this paper is to report illustrative cases to enhance the distinctive features of each disposition.

Double internal carotid origin of the ophthalmic artery with ruptured aneurysm of the posterior communicating artery. A case report

SUMMARY

We report a case of double origin of the ophthalmic artery from the carotid siphon. The persistence of the primitive dorsal ophthalmic artery, together with a ventral ophthalmic artery, constitutes the double origin of the ophthalmic artery. Remnant of intraorbital anastomoses formed by these two arteries is demonstrated. This represents a rare configuration of double origin of the arterial blood supply, which is discovered "incidentally" in a patient harboring a ruptured aneurysm of the posterior communicating artery. The embryology of the ophthalmic artery and a possible association between vascular anomaly and arterial aneurysm can be envisaged.

5-year Angiographic and Clinical Follow-up of Coil-embolised Intradural Saccular Aneurysms. A Single Center Experience

SUMMARY

The purpose of the paper is the follow-up of embolised intradural saccular Arterial Aneurysms (AA), excluding giant, dissecting, inflammatory, fusiform or AA associated to BVAM. Since its introduction in 1991, the Guglielmi Detachable Coil has offered protection against aneurysmal rebleeding in the critical few days and months after SAH regardless of the grade. A number of questions remain: is complete angiographic obliteration necessary at first embolisation? What duration of clinical / angiographic follow-up (FU) is required to ensure the risk of haemorrhage has been eliminated? What is the long-term protection against rebleeding? One hundred and two patients with 160 intradural saccular AA embolised before april 1997 were selected for this study. They had at least 5-yrs clinical FU, of which 22 patients had a mid- term (3 years) and 45 patients had a 5-year or more angiographic FU (mean 67,7 months per patient). Twenty-eight embolised AAs with 100% occlusion at 1 year, remained unchanged on the 5-year angiograms. A further 14 patients with complete occlusion at 1 year showed persisting complete occlusion on angiogram at 3-years FU, which in our series means that complete occlusion after the first year post-embolisation implies that the aneurysm will remain completely occluded. All secondary spontaneous thromboses (27.6% of cases), occurred during the first year pos- embolisation. In six patients with subtotal or partial occlusion no change was seen for three consecutive years of FU; none showed later change at 5-year angiography. Below 80% occlusion our series does not provide enough information but we consider the situation instable. No mortality related to the procedure was observed in the unruptured AA group.No bleeding or re-bleeding has occurred since the beginning of our experience (1993) in saccular AA treated by GDC-Coil. Coil-embolisation of properly selected patients is effective in protecting against bleeding or re-bleeding at short and long-term with stable morphological results provided a strict follow-up control is established at short term.