Azygous Anterior Cerebral Artery Research Articles

Azygous anterior cerebral artery thrombosis causing bifrontal infarcts with abnormal behavior

Azygous anterior cerebral artery (AACA) is a rare anatomical variant and its occlusion may cause bifrontal infarct with variable neurological deficit and clinical presentation. In our case AACA thrombotic occlusion caused bifrontal infarcts leading to abnormal behavior. Early imaging with CT angiography or MRI with MRA is the key for early diagnosis and prompt management.

A RARE CAUSE OF PARAPLEGIA: DISTRIBUTIVE SHOCK CAUSING BORDER ZONE STROKES

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Simultaneous bilateral cerebrovascular infarction is relatively uncommon and is an entity seen rarely in watershed cerebral infarctions which occur at the border between cerebral vascular territories in the setting of severe hypotension. CASE PRESENTATION: 84-year-old male with history of CAD, cerebellar stroke, peripheral arterial disease was admitted to the ICU with distributive shock and intubated for toxic metabolic encephalopathy. Initial CT head on admission was unremarkable. On day 2 of hospitalization his neuro assessment was notable for bilateral lower extremity paresis with preservation of sensation, proprioception and temperature but had sluggish reflexes and loss of motor strength. Repeat CT head did not show a bleed and subsequently, MRI brain with MRA head and neck revealed bilateral acute anterior cerebral artery strokes. Given the location and duration of symptoms he was not a TPA candidate and was treated with medical management with aspirin and statin. Echocardiogram and carotid ultrasounds were done that were unremarkable for embolic cause of stroke. DISCUSSION: The anterior cerebral artery is a major vessel supplying blood to the interhemispheric region. ACA territory infarction accounts for only 0.3% to 4.4% of cerebral infarctions. Bilateral ACA infarction is even rarer. Twenty-seven cases of ACA territory infarction were reported among 1490 cases of cerebral infarction in the Lausanne Stroke Registry; among them, only two cases had bilateral ACA territory infarction. Bilateral ACA infarction can occur due to vasospasm in the setting of subarachnoid hemorrhage caused by a rupture of aneurysms of the anterior communicating arteries or distal ACAs, thrombosis or embolism in case of anomaly of circle of Willis or bilateral anaplastic ACAs. In our patient the area of infarction was in a watershed zone bilaterally, unfortunately affected by hypotension which is rare in the absence of any of the above-mentioned anomalies as predisposing factors. The true incidence of bilateral ACA infarction is unknown, with few cases reported in the literature. CONCLUSIONS: This case report highlights the possibility of developing simultaneous bilateral cerebral infarctions in the setting of profound systemic hypotension and shock, especially if the patient has baseline chronic small vessel changes. REFERENCE #1: Orlandi G, Moretti P, Fioretti C, Puglioli M, Collavoli P, Murri L. Bilateral medial frontal infarction in a case of azygous anterior cerebral artery stenosis. Ital J Neurol Sci. 1998;19:106–108. doi: 10.1007/BF02427567. [PubMed] [CrossRef] [Google Scholar] REFERENCE #2: Gacs G, Fox AF, Barnett HJ, Vinuela F. Occurrence and mechanisms of occlusion of the anterior cerebral artery. Stroke. 1983;14:952–959. [PubMed] [Google Scholar] REFERENCE #3: Bogousslavsky J, Regli F. Anterior cerebral artery territory infarction in the Lausanne Stroke Registry. Clinical and etiologic patterns. Arch Neurol. 1990;47:144–150. [PubMed] [Google Scholar] DISCLOSURES: No relevant relationships by Imama Ahmad, source=Web Response No relevant relationships by Christine Blaski, source=Web Response No relevant relationships by Sneha Lakshman, source=Web Response

Pericallosal berry aneurysm associated with azygous anterior cerebral artery – a case report

Introduction. Azygos anterior cerebral artery is a rare variant of the anterior segment of the circle of Willis caused by an unusual fusion of the normally paired A2 segments of the anterior cerebral artery (ACA). Despite its rare occurrence, it is associated with various vascular and structural cerebral abnormalities, particularly berry aneurysms. Aim. We aimed to present a case of a 41-year-old female patient who presented to our neurology department with complaints of headache. Description of the case. She had a positive paternal history of aneurysmal subarachnoid hemorrhage. Magnetic resonance angiography (MRA) of her brain revealed an azygos ACA (bifurcating into two pericallosal arteries) which was associated with a saccular aneurysm at its bifurcation point. She was referred to the interventional radiology department for preventive endovascular treatment. Conclusion. Azygos ACA carries a high risk of aneurysm development and its occlusion can potentially compromise blood supply to both cerebral hemispheres. It is therefore crucial for clinicians to be aware of its significance and to report its presence in angiographic studies.

Azygous Anterior Cerebral Artery Acute Occlusion Managed With Endovascular Mechanical Thrombectomy: 2-Dimensional Operative Video

Mechanical thrombectomy has become the standard of care for management of most acute large-vessel occlusion (LVO) strokes. Most intracranial occlusions are located in the middle cerebral and internal carotid arteries. We present a unique case of acute occlusion of an azygous anterior cerebral artery (ACA). A 59-yr-old man with known hypertension and alcoholism presented with right hemiparesis, right facial palsy, aphasia, and dysarthria. His initial National Institutes of Health Stroke Scale (NIHSS) score was 20. Computed tomographic angiography and perfusion imaging demonstrated acute bilateral ACA occlusion with viable penumbra and preserved cerebral blood volume. The patient was not a candidate for intravenous tissue plasminogen activator because he presented with a wake-up stroke. After consent was obtained from his family, the patient was taken urgently for endovascular recanalization. Digital subtraction angiography confirmed acute azygous ACA occlusion. Under conscious sedation, the patient underwent mechanical thrombectomy with a stent retriever and a large-bore aspiration catheter. Successful revascularization (thrombolysis in cerebral infarction [TICI] grade 3) of the azygous ACA and both A2 arteries was obtained after 2 attempts and the use of a different stent retriever (first a 3×30 mm Trevo [Stryker Neurovascular, Kalamazoo, Michigan] and then a 4×40 mm Solitaire Platinum [Medtronic, Dublin, Ireland]). A reperfusion catheter was used during both attempts. No procedure-related complications occurred. The patient was discharged to a rehabilitation facility 3 d after the procedure with an NIHSS score of 2. In this video, we present the operative nuances of an uncommon location of LVO and its endovascular management.

In Situ Left Azygous Anterior Cerebral Artery to Right Pericallosal Artery Bypass for Treatment of a Giant Right A1/2 Aneurysm: 2-Dimensional Operative Video.

Here we present a 46-yr-old man with recurrent syncopal episodes thought to be of cardiac origin. He was eventually found to harbor a giant, partially thrombosed, saccular aneurysm arising from the A1/A2 segment of the right anterior cerebral artery with foramen of Monro obstruction and a trapped left-sided ventricular system. An azygous left A2 artery segment supplied both callosomarginal arteries. We performed an in situ side-to-side anastomosis between the distal left azygous anterior cerebral artery and the right pericallosal artery, which was previously supplied by the right A1. The right A1 was clip ligated, and the aneurysm evacuated with an ultrasonic aspirator. Postoperatively, the patient did well with no recurrence of the aneurysm and resolution of his preoperative obstructive hydrocephalus. He continues to be independent>7 yr post surgery. His 6-mo follow-up angiogram revealed a patent bypass.

Variations of the anterior part of circle of Willis in human cadavers: a dissection study

Background: Vascular anatomy of anterior cerebral artery (ACA), anterior communicating artery (ACoA) and its branches is quite complex and known for its variations. Most of the variations have been reported on posterior cerebral and posterior communicating arteries. However, there are very few case reports regarding variations encountered in the ACA and ACoA. Hence, the present study was undertaken to study the origin, course and termination of ACA, to observe the ACoA, and to observe variations associated with them . Methods: 30 human brain specimens were removed from embalmed cadavers. Vernier calliper was used to measure the length and external diameter of ACA and ACoA. Variations were observed with reference to presence or absence, size, shape and mode of anastomosis. Results: Out of 30 cases; in anterior part, the circle of Willis was incomplete in 1 case and anomalous in 5 cases. Pre-communicating ACA (A1 segment) was absent in 2 cases and hypoplastic in 1 case. Azygous ACA was seen in 3 cases. ACoA was absent in 4 cases. Out of the 26 cases of ACoA, ‘H’ shaped ACoA – ACA complex was most commonly found. Conclusions: Variations of the anterior part of circle of Willis are not quite rare as believed.

Bilateral ascending weakness in a patient with Azygous Anterior Cerebral Artery Stroke. (P1.040)

Bilateral ascending weakness in a patient with Azygous Anterior Cerebral Artery Stroke. (P1.040)

Magnetic resonance angiographic investigation of azygous alias monkey type anterior cerebral artery – Incidence and clinical significance

IntroductionAzygous anterior cerebral artery (ACA) is one of the extremely rare variant occuring in the A2 segment of ACA, where the bilateral A1 segments unite together to form a single midline trunk. This trunk supplies both ACA territories. It has been also referred to as the unpaired pericallosal stem artery, unpaired anterior cerebral artery, common anterior cerebral trunk and azygos pericallosal artery. Method1.5 T (GE OPTIMA MR 360) was used for obtaining the angiographs, 114 MRA were reviewed, 90 male and 24 female, aged between 20 and 75 years. ResultThe Azygous type anterior cerebral artery was present in (3.5%), in (1.75%) a long trunk depicting the classical Azygous anterior cerebral artery was present, while in (1.75%) a short median stem was present. DiscussionThis type of presentation is a risk factor for development of aneurysm in distal part of ACA due to alteration of hemodynamics, sometimes this variation may be associated with vascular or nonvascular neurological anomalies like arteriovenous malformations, defects of septum pellucidm, Holoprosencephaly, meningomyelocele.

Bihemispheric posterior inferior cerebellar artery occurring with an azygos anterior cerebral artery: case study.

Variations in intracranial vasculature are well known. We report a rare anatomic variation in a patient who underwent cerebral angiography for suspected intracranial aneurysm. Digital subtraction angiography revealed a bihemispheric posterior inferior cerebellar artery (PICA) and an azygous anterior cerebral artery (ACA). There was no evidence of any aneurysm or vascular abnormality. To our knowledge, this is the first reported case of a patient with a common PICA supplying both the cerebellar hemispheres and a common ACA supplying ACA territory bilaterally. It is important for the physician to be aware of these anatomical variations in order to differentiate a normal variant from a pathological condition.

Azygous Anterior Cerebral Artery and Associated Aneurysms: Detection and Identification Using 3‐Dimensional Time‐of‐Flight Magnetic Resonance Angiography

The azygous anterior cerebral artery (Az) is a rarely observed anomaly of the anterior cerebral artery, and its associated aneurysm is even rarer. Our aim was to evaluate 3-dimensional time-of-flight magnetic resonance angiography (3-D-TOF MRA) in the diagnosis of Az and associated aneurysms. Three thousand five hundred seventy-two consecutive patients underwent 3-D-TOF MRA at 3.0 T. Postprocessing techniques, including volume rendering (VR) and single artery highlighting, were performed by a 3-D specialist. All MRA data and clinical information were recorded and stored in a database for further analysis. Fourteen patients (.39%) were identified as having an Az. Among these cases, 3 males (21.43%) had an aneurysm located at the distal bifurcation of the Az, with a mean size of 9.43 ± 3.33 mm. In MRA, the common trunk of the Az was slightly larger in diameter than the A1 segment (2.62 ± .35 mm vs. 2.54 ± .35 mm; P = .008). With the VR technique, 3-D-TOF MRA is feasible and valuable in detecting an Az and associated aneurysm. Our MRA-based study has proved that the Az is a rare anomaly but has a relatively high incidence of associated aneurysms.

A Ruptured Aneurysm at the Infraoptic Azygous Anterior Cerebral Artery with the Contralateral Internal Carotid Artery Agenesis Treated by Y-stent Assisted Coil Embolization

Infraoptic anterior cerebral artery (ACA) is an extremely rare congenital anomaly. This anomalous artery usually arises from the intradural internal carotid artery (ICA) near the level of the ophthalmic artery (OA) or rarely from the extradural ICA. This anomaly frequently harbors a cerebral aneurysm, and may involve other coexisting vascular anomalies. In the case of this anomaly, surgical treatment of the aneurysm at the proximal ACA or anterior communicating artery (ACoA) may sometimes be difficult, because the veiled proximal ACA by the optic nerve would make proximal control inconvenient and the vertical midline segment of the proximal ACA would frequently form a superiorly directing aneurysm with a relatively high position. We report on an extremely rare case of a ruptured aneurysm at the infraoptic azygous ACA, possibly having an extradural origin, accompanied by contralateral ICA agenesis, and also introduce a feasible method for treatment by Y-stent assisted coil embolization.

Two new Brazilian patients with Gómez–López‐Hernández syndrome: Reviewing the expanded phenotype with molecular insights

Gómez-López-Hernández (GLH) syndrome or cerebello-trigeminal dysplasia is a neurocutaneous syndrome whose etiology is unknown at the present time. We report two additional Brazilian patients, including the oldest one known to date (age 29). Here, we review the expanded phenotype in four patients with new clinical, psychiatric, radiological, and molecular investigations. One patient may have hypomania within the bipolar spectrum disorder with onset in childhood and adolescence. Primary growth hormone (GH) deficiency was ruled out in all patients, although one of them might have developed secondary GH deficiency due to partial hypopituitarism following severe hydrocephalus. Brain magnetic resonance angiography disclosed no azygous anterior cerebral artery (ACA) but only normal variants. Molecular analysis of the lysosomal acid phosphatase gene (ACP2) was performed, but no pathogenic mutations were identified. We present an overview of the phenotypic features of all patients described to date. There are currently 12 unrelated patients reported in the literature, 5 of whom are Brazilian. We discuss new molecular insights and speculate about the pathogenesis of GLH syndrome.

Persistent trigeminal artery and associated vascular variations

Persistent trigeminal artery (PTA) is the most frequent type of persistent primitive carotid-basilar artery anastomoses. Persistent trigeminal artery is usually associated with small or absent posterior communicating artery (Pcom). It may also be associated with hypoplastic vertebral and basilar arteries. Patients may present with symptoms related to hypo-perfusion of posterior circulation or microembolization from carotid artery to posterior circulation. We are presenting a 60-year-old who had recurrent episodes of vertigo and parasthesia, in whom MR angiography revealed a medial, Saltzman type 1 PTA on the left with absent ipsilateral Pcom, duplicated ipsilateral superior cerebellar artery, hypoplastic A1 segment of contralateral anterior cerebral artery (ACA), azygous ACA and hypoplastic ipsilateral vertebral artery.

Gomez-Lopez-Hernandez syndrome

We describe a case of Gomez-Lopez-Hernandez syndrome in an 18-month-old boy. Imaging findings included rhombencephalosynapsis with a single dentate nucleus. In addition, MR angiography revealed an azygous anterior cerebral artery. The clinical presentation, MRI findings and pathogenesis are discussed.

Microsurgical anatomy and clinical significance of the anterior communicating artery and its perforating branches.

Precise identification of the anomalous anterior communicating artery (ACoA) or the perforating branches of the ACoA is usually difficult on preoperative angiograms because of the vascular complexity around the ACoA and its small-caliber branches. The purpose of this study was to review the microsurgical anatomy of the ACoA and its branches to show their importance for the interhemispheric trans-lamina terminalis approach and ACoA aneurysmal surgery. In 30 cadaver brains, the ACoA and its branches were examined under magnification using a surgical microscope. The ACoA was evident in all specimens and had variations consisting of plexiform (33%), dimple (33%), fenestration (21%), duplication (18%), string (18%), fusion (12%), median artery of the corpus callosum (6%), and azygous anterior cerebral artery (3%). The perforating branches were also observed in all cadaver brains. They were classified into subcallosal, hypothalamic, and chiasmatic branches according to their vascular territories. The subcallosal branch, usually single and the largest, supplied the bilateral subcallosal areas, branching off to the hypothalamic area. The hypothalamic branches, multiple and of small caliber, terminated in the hypothalamic area. The incidence of anomalous ACoA was higher than has been previously reported, and any segment of the anomalous ACoA may have perforating branches regardless of diameter. Among the three branches, the subcallosal branch is the most important because it feeds bilateral subcallosal areas branching to the hypothalamic area.

Optimum degree of hemodilution for brain protection in a canine model of focal cerebral ischemia.

The ability of hemodilution to lower blood viscosity and increase cerebral blood flow has been proven experimentally; however, the optimum hematocrit for maximum oxygen delivery to ischemic brain tissue is not known, and a study was designed to determine this. Fifty dogs were selected for inclusion in the study using criteria based on changes in somatosensory evoked potentials at the time of arterial occlusion, which were found in a previous study to predict the development of a moderate infarction of relatively constant size. Infarctions were induced by permanent occlusion of the left middle cerebral artery and the azygous anterior cerebral artery. The animals selected for inclusion were divided into five groups of 10 dogs each: 1) a control group; 2) a group with 25% hematocrit; 3) a group with 30% hematocrit; 4) a group with 35% hematocrit; and 5) a group with 40% hematocrit. Isovolemic hemodilution was accomplished 1 hour after occlusion of vessels using dextran infusion and blood withdrawal. The animals were sacrificed after 6 days and infarction volume was determined from fluorescein-stained sections. Statistical analysis was performed using Student's t-test and one-way analysis of variance. Mean infarction volume for each group, expressed as a percentage of total hemispheric volume +/- 1 standard error of the mean, was 28.3% +/- 2.8% for the control group, 33.6% +/- 3.4% for the 25% hematocrit group, 17.1% +/- 2.2% for the 30% hematocrit group, 29.2% +/- 4.3% for the 35% hematocrit group, and 29.9% +/- 2.1% for the 40% hematocrit group. The 30% hematocrit group showed the smallest average infarction size and this size differed significantly (p = 0.02) from the average infarction size in the control animals. These results show that, in this model of focal ischemia, a hematocrit of approximately 30% is optimum for protecting the brain.

The Use of Somatosensory Evoked Potential Monitoring to Produce a Canine Model of Uniform, Moderately Severe Stroke with Permanent Arterial Occlusion

To develop a reliable canine model of cerebral infarction of moderate size, we compared infarctions caused by permanent occlusion of the following vessels in 42 dogs: 1) the middle cerebral artery (MCA), 2) the MCA and azygous anterior cerebral artery (ACA), 3) the MCA, azygous ACA, and posterior cerebral artery (PCA), and 4) sham-operated controls. The infarction volume was determined at 6 hours in half the animals and at 6 days in the others. Studies of somatosensory evoked potentials (SSEPs) and regional cerebral blood flow (rCBF) were performed before and after arterial occlusion, and good correlation was observed between the decrease in amplitude of the SSEPs and the decrease in rCBF observed after arterial occlusion. Only the groups in which the MCA and azygous ACA were occluded showed moderate infarctions of relatively consistent size. Analysis involving all groups revealed that the animals with SSEP amplitude preserved after vessel occlusion had only small infarctions; thus, preservation of SSEP amplitude after occlusion of the MCA and azygous ACA could in the future be used prospectively as a rejection criterion to improve the uniformity of infarction size. Conversely, animals with loss of SSEP amplitude after vessel occlusion had infarctions of moderate to large size; thus, loss of SSEP amplitude after MCA occlusion alone could in the future be used prospectively as a rejection criterion. When these rejection criteria were retrospectively applied to the groups in which both the MCA and azygous ACA were occluded, the resulting mean infarction volumes +/- 1 SEM) for the acute and chronic subgroups were 20.3 +/- 2.8% and 38.2 +/- 4.5% of the hemisphere, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomical bases for surgical approach to the initial segment of the anterior cerebral artery. Microanatomy of Heubner's artery and perforating branches of the anterior cerebral artery.

Both the Heubner's artery and the perforating branches of the anterior cerebral artery (ACA) were present in all thirty-three examined brains. Heubner's arteries varied in number from 1 to 3. They originated from the distal (A2) segment of the ACA in 34% of the cases, from the proximal (A1) segment of the ACA in 17%, at the level of the anterior communicating artery in 21%, from the fenestration of the ACA in 8%, and in all the other cases (20%) from the azygous anterior cerebral artery, accessory middle cerebral artery, frontopolar artery and, finally, by the common stem with the medial orbitofrontal artery. Heubner's artery most commonly terminated dorsal and lateral to the carotid bifurcation, at an average distance of 4.8 mm. The mean diameter of Heubner's artery was 662 microns, that of its extracerebral collateral branches 205 microns, of the terminal branches 462 microns, and of the intracerebral segments 354 microns. Perforating branches varied in number from 1 to 12 with an average of 6.6. The majority of the branches originated from the initial 6.1 mm of the A1 segment. These vessels terminated close to the carotid bifurcation, at an average distance of 3.8 mm. All the perforating branches were divided into small (average 122 microns in diameter) and large (average 325 microns). The mean diameter of intracerebral segments was 276 microns, and that of terminal branches 259 microns. It was concluded that the anatomical characteristics of both the recurrent artery and the perforating branches can be of a great significance in cerebrovascular diseases.

Holoprosencephaly in neurosurgical practice

The clinical, angiographic, and pneumoencephalographic features of seven cases with holoprosencephaly are reported. Three of the alobar type in this series revealed the facial dysmorphia characteristic of the anomaly. In the other four cases (one alobar, one semilobar, and two lobar), such facial anomaly was absent, and the diagnosis was achieved only after contrast studies. An azygous anterior cerebral artery running over the cerebral surface due to a defective interhemispheric fissure is pathognomonic for alobar and semilobar holoprosencephaly. Dysgenesis of the deep venous system was found in alobar, semilobar, and lobar holoprosencephaly, a finding helpful in diagnosis, especially of the lobar type. Air study and computerized tomography scan revealed incomplete separation of the ventricular system. The basic nature of holoprosencephalization and its differentiation from non-holoprosencephalic malformation are discussed. Six of the seven patients reported had hydrocephalus.