Accessory posterior cerebral artery (hyperplastic anterior choroidal artery) associated with contralateral accessory middle cerebral artery incidentally diagnosed by magnetic resonance angiography.

PURPOSE: To describe a case of accessory posterior cerebral artery (PCA) [hyperplastic anterior choroidal artery (AChA)] associated with contralateral accessory middle cerebral artery (MCA) incidentally diagnosed by magnetic resonance (MR) angiography. METHODS: A 71-year-old man with paroxysmal atrial fibrillation underwent cranial MR imaging and MR angiography of the intracranial region using a 1.5-T scanner for the evaluation of brain and vascular lesions. RESULTS: On MR angiography, two right PCAs of equal size arose from the internal carotid artery instead of the basilar artery. Additionally, a small left MCA branch arose from the proximal A2 segment of the anterior cerebral artery (ACA). CONCLUSION: One of the branches of the PCA rarely arises from the AChA. This variation is referred to as a hyperplastic AChA or accessory PCA. The latter name was recently proposed and may be more appropriate than the former name. An MCA branch arising from the ACA is called an accessory MCA. It is a frontal branch of two types: proximal-origin and distal-origin. The distal-origin accessory MCA arises from the distal A1 segment, A1-A2 junction or proximal A2 segment. Distal-origin accessory MCAs are rare. Our patient had two rare variations: an accessory right PCA and a distal-origin accessory left MCA. To identify cerebral arterial variations, especially accessory MCA, volume-rendering images are more useful than maximum-intensity projection images on MR angiography.

Anatomical Variations and Anomalies of the Anterior Communicating Artery Complex.

BACKGROUND: Intracranial arteries have a high rate of variation, but a clear schematic overview is lacking. In this pictorial review we classify and depict all variations and anomalies within the anterior communicating artery complex. METHODS: PubMed was searched with the terms "Anterior Communicating Artery" AND "Variations" OR "Anomalies." Articles were selected based on their description of variants. Cross-referencing was used to broaden the range of variations. Surgical view during pterional craniotomy and transsylvian approach was used as a baseline for schematic drawings of the variations. RESULTS: A total of 42 variants were identified, schematically drawn and classified into A1-A2 segment, anterior communicating artery, and the recurrent artery of Heubner. CONCLUSIONS: The anterior communicating artery complex consists of the anterior cerebral artery, anterior communicating artery and the recurrent artery of Heubner. An overview of these variations may be helpful in distinguishing pathology from anatomical variations, assist neurosurgeons during clipping of cerebral aneurysms, and support interventional radiologists during endovascular treatments. This article summarizes the current knowledge of anatomical variations within the anterior communicating artery complex, their prevalence and clinical relevance. A total of 42 variants were identified and schematically depicted. We encourage all who diagnose, treat, and study the anterior communicating artery complex to use this overview for a uniform and better understanding of its anatomy.

Left anterior cerebral artery arising from a right internal carotid artery: a rare case of carotid-anterior cerebral artery anastomosis.

Carotid-anterior cerebral artery anastomosis (carotid-ACA anastomosis) is described as infrequent vascular connections between the pre-ophthalmic segment of the internal carotid artery (ICA) and the A1 segment of the anterior cerebral artery (ACA). The embryological origin of these variant is still unclear and they are often associated to other vascular anomalies of the circle of Willis, as well as to the presence of aneurysms. Carotid-ACA anastomosis is often right-sided although left and bilateral cases have also been described. We report a rare case by MR angiography of a carotid-ACA anastomosis in which the abnormal vessel arises from the right ICA and takes an infraoptic course to join the A2 segment of the contralateral ACA, making this vascular anomaly function as a 'left ACA with an origin at the right ICA'. The A1 segment of the left ACA is absent and both A2 segments of the ACAs present fenestration. To our knowledge, no similar cases have been reported in English literature so far.

[A case of crossed aphasia following infarction in the right anterior cerebral artery territory].

We report a patient presenting with crossed aphasia following infarction in the territory of the right anterior cerebral artery (ACA). A right-handed 68-year-old woman without a history of correction had acute disturbance of consciousness, left hemiparesis predominant in the lower extremity, speech disorder and left unilateral spatial neglect during the admission due to hypertensive emergency. No other family member was left-handed. MRI of the head revealed acute phase infarction in the territory of the right ACA: mesial frontal lobe including the supplementary motor area, anterior cingulate gyrus, and the corpus callosum. Language symptoms in the subacute phase included difficulty in initiation, slow speech rate, loss of intonation and phonetic paraphasia, and accompanying errors in comprehension, repetition, reading, and writing letters. These symptoms suggested "anomalous" type crossed aphasia. No limb apraxia, construction disorder or left unilateral spatial neglect was observed in this period. Only a few cases of crossed aphasia due to infarction in the territory of the ACA have been reported so far. However, language and concomitant symptoms differs, depending on each case, suggesting a difference in individual cerebral lateralization.

Selective clipping of giant anterior communicating artery aneurysms remains a reliable therapeutic option.

BACKGROUND: Giant anterior communicating artery (AcomA) aneurysm represent a significant surgical challenge. Our study aimed to discuss the therapeutic strategy in patients with a giant AcomA aneurysm treated by selective neck clipping through a pterional approach. METHODS: Among all operated patients from an intracranial aneurysm between January 2015 and January 2022 (n = 726) in our institution, three patients with a giant AcomA aneurysm treated by neck clipping were included. Early (<7days) outcome was noted. Early postoperative CT scan was performed in all patients to detect any complications. Early DSA was also performed to confirm giant AcomA aneurysm exclusion. The mRS score was recorded 3 months after treatment. The mRS≤ 2 was considered as a good functional outcome. Control DSA was performed one year after treatment. RESULTS: In the three patients, after a large frontopterional approach, a selective exclusion of their giant AcomA aneurysm was obtained after a partial pars orbitalis of the inferior frontal gyrus resection. Ischemic lesion was noted in 1 patient and chronic hydrocephalus in 2 patients with ruptured aneurysm. The mRS score after 3 months was good in 2 patients. Long term complete occlusion of the aneurysm were noted in the three patients. CONCLUSION: Selective clipping of a giant AcomA aneurysm is a reliable therapeutic option after a careful evaluation of local vascular anatomy. An adequate surgical exposure is frequently obtained through an enlarged pterional approach with an anterior basifrontal lobe resection, especially in an emergency situation and/or in case of high position of anterior communicating artery.

Fenestrated Anterior Cerebral Artery, Anterior Communicating Artery, with Accessory Middle Cerebral Artery-A Conglomeration of Embryologically Different Entities in a Single Individual.

Cerebral arterial fenestrations are anatomic variants of undetermined significance where there is a division of a single vessel into at least 2 channels, each having endothelial and muscular layers, that coalesce to a single lumen in the distal course of the vessel. The basilar artery is the most common site, followed by the anterior communicating artery. The accessory middle cerebral artery is defined as the anomalous origin of the vessel from the anterior cerebral artery and its further course along the sylvian fissure parallel to the middle cerebral artery. The embryologic basis of all these has been explained by studies on human embryological development by Padget et al. However, simultaneous existence of all 3 anomalies in a single individual has never been reported. Here we present a case of medial sphenoid wing meningioma with these incidental findings during workup and further delineation of anatomy following surgical resection of meningioma.

Unreported branching pattern of the triplicated anterior cerebral artery associated with multiple bilateral variants of the superior cerebellar artery detected by computed tomography angiography and 3D modeling.

A 26-year-old patient underwent a successful ablation of Grade 2 diffuse astrocytoma of the right parietal lobe. The postoperative computed tomography angiography with 3D modeling revealed a residual avascular porencephalic cyst. Otherwise, multiple arterial variants have been encountered. First, the left A1 segment was fenestrated, and three A2 segments arose from the anterior communicating artery. The middle A2 segment was dominant and supplied left callosomarginal and both pericallosal territories. The right A2 segment supplied the right callosomarginal territory, while the left A1 was limited to the left orbitofrontal and frontopolar territories. This configuration represents a triplicated anterior cerebral artery with an unusual branching pattern not included in the classification of Baptista. In addition, on both sides, superior cerebellar artery duplication was present, with one arising from the basilar artery and the other from the P1 segment of the ipsilateral posterior cerebral artery. The left lower superior cerebellar artery was early bifurcated. It is the first time such a cerebrovascular configuration has been reported. Because of the several clinical and surgical applications of the anterior cerebral artery and superior cerebellar artery variants, this case report is of utmost interest to anatomists, radiologists, and neurosurgeons.

Tela-choroidea-to-anterior-cerebral-artery distance (TACAD): novel marker on color Doppler to identify fetuses with complete or partial agenesis of corpus callosum.

OBJECTIVES: To assess objectively the course of the anterior cerebral artery (ACA) by measuring its distance to the tela choroidea in the midsagittal view, and to compare this distance in normal fetuses with that in those with agenesis of the corpus callosum (ACC), a condition known to be associated with an abnormal course of the ACA. METHODS: The tela-choroidea-to-anterior-cerebral-artery distance (TACAD) was measured in the midsagittal view of the brain on color Doppler, between the anterior border of the tela choroidea and the ACA at the level of the callosal genu. Reference ranges in relation to gestational age were established in a prospective, cross-sectional study of 253 normal healthy fetuses between 19 and 36 weeks of gestation. The study group included fetuses with complete ACC (n = 28) or partial ACC (n = 18). RESULTS: TACAD of normal fetuses showed an increase during the second half of pregnancy, with a mean value of 10.1 mm and 14.2 mm at 22 and 30 weeks of gestation, respectively. All (28/28) fetuses with complete ACC and 83% (15/18) of those with partial ACC had significantly shorter TACAD, with mean values of 3.9 mm and 6.6 mm, respectively. CONCLUSIONS: TACAD is a measurement that is simple to obtain during fetal color Doppler neurosonography, which enables quantification of the course of the ACA and pericallosal artery. TACAD is shorter in fetuses with complete or partial ACC than in normal fetuses and provides an objective, quantifiable value, rather than merely descriptive information. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Delayed rupture of traumatic anterior cerebral artery A4 segment aneurysm: A case report.

RATIONALE: Delayed rupture of traumatic intracranial aneurysms is relatively rare, and traumatic anterior A4 segment aneurysms may be associated with trauma to the cerebral falx. The mortality rate in patients with delayed traumatic rupture of intracranial aneurysms is>50%. Therefore, early diagnosis and treatment are critical. Herein, we present a case of a patient who did not have an intracranial aneurysm on computed tomographic angiography (CTA) after admission. Subsequently, the patient consciousness deteriorated, and CTA revealed aneurysm and bleeding. PATIENT CONCERNS: A 55-year-old man fell from a 3-meter-high truck and was unconscious. During the following few hours, the gradually regained consciousness. No intracranial aneurysms were found on CTA of the patient head immediately after admission. DIAGNOSES: The final diagnosis was delayed rupture of traumatic intracranial aneurysms. INTERVENTIONS: The patient underwent endovascular and symptomatic treatments. OUTCOMES: The patient gradually recovered and was referred to the rehabilitation department for further treatment. LESSONS: Considering the catastrophic consequences of the disease, we should review CTA or digital subtraction angiography many times after admission, and take appropriate surgical procedures in time.

The application of high-resolution vessel wall imaging in the in situ bypass surgeries for complex anterior cerebral artery aneurysms.

OBJECTIVE: Complex anterior cerebral artery (ACA) aneurysms are still technically challenging to treat. Bypass surgery is needed to achieve aneurysm obliteration and ACA territory revascularization. Severe atherosclerosis of aneurysm walls can cause clip slippage, intraoperative rupture, postoperative ischemic events. How to assess the atherosclerotic changes in vascular walls by high-resolution vessel wall magnitude resonance imaging (VWI) is the key question in complex ACA aneurysm surgical management. METHODS: This retrospective single-center study included eight patients diagnosed with complex anterior cerebral arteries admitted to our hospital for bypass surgery from January 2019 to April 2022. We discussed the application of VWI in aneurysms treated with in situ bypass and reviewed previous experience of revascularization strategies for complex ACA aneurysms. RESULTS: In this study, we treated 8 cases of complex ACA aneurysms (3 communicating aneurysms/5 postcommunicating aneurysms) over the prior one year. In situ side-to-side anastomosis (1 A2-to-A2/6 A3-to-A3) was performed in seven cases, and trapping combined with excision was performed in another case. Following bypass, complete trapping was performed in 4 cases, and proximal clipping was performed in 3 cases. No surgery-related neurological dysfunctions were observed. The final modified Rankin scale was 0 in seven of the eight cases and 2 in one case. CONCLUSION: High-resolution VWI, as a favorable preoperative assessment tool, provides insight into patient-specific anatomy and microsurgical options before operations, which can help neurosurgeons develop individualized and valuable surgical plans.

Funnel Shaped Anterior Communicating Artery Fenestration Mistaken for an Aneurysm: A Cautionary Tale.

This report portrays a case of a funnel shaped anterior communicating artery (ACoA) fenestration which was mistaken as a small A1 aneurysm in a subarachnoid hemorrhage case. Although tridimensional rotational digital subtraction angiography improves aneurysm diagnosis specially at the ACoA complex, current spatial resolution might leave behind a considerable percentage of ACoA fenestrations. This may lead to diagnostic errors and unnecessary treatments risking iatrogenic complications. Luckily for our patient, a concomitant aneurysm warranted clipping and subsequent surgical exploration of the ACoA complex revealed the pitfall, thus preventing further action. Interestingly, another group of authors who reported similar misdiagnosis with ACoA aneurysms were able to prevent a third error, thanks to the experience acquired with 2 prior cases. Therefore, this clinical image aims to raise wider awareness of the need for very cautious consideration of imaging depicting small and/or atypical aneurysms in the ACoA complex.

Bihemispheric Right Anterior Cerebral Artery, Fenestrated Origin of the Left Pericallosal Artery, Fenestrated Basilar Artery, Double Right Posterior Cerebral Artery.

Anatomical variations of the cerebral vasculature are frequently encountered. The archived magnetic resonance angiogram of a 62-year-old male patient was studied anatomically on planar slices and 3-dimensional volume renderings. Numerous anatomical variants were found in that single case. In the vertebrobasilar system were found: the proximal basilar artery fenestration, with a unilateral origin from that fenestration of an anterior inferior cerebellar artery, and the unilateral origin of the superior cerebellar artery from the P1 segment of the main posterior cerebral artery (PCA). There were also unilateral variants of the right internal carotid artery (ICA): a subvariant of an accessory PCA leaving the ICA as a hyperplastic anterior choroidal artery and united to the main PCA by a short communicating branch, distinctive of the posterior communicating artery in that side (unilateral double PCA); a right bihemispheric anterior cerebral artery (ACA) but with complete agenesis of the contralateral A1 ACA segment; from the right ACA continued an anatomically normal ipsilateral A2 segment and a short transverse contralateral A2 that, in turn, sent off long pericallosal and callosomarginal arteries; and fenestrated origin of the left pericallosal artery. Therefore, an arterial variant in one of the main cerebral circulations could not exclude anatomical variants in the other cerebral circulatory beds.

False Absence of the Anterior Communicating Artery and a Median Artery of Corpus Callosum.

The anterior communicating artery (AComA) normally joins the anterior cerebral arteries (ACAs) when they change their directions from horizontal to vertical. Each postcommunicating segment of the ACAs commonly sends off the callosomarginal artery (CMA) and continues as the pericallosal artery. While documenting the archived computed tomography angiogram of a 61-year-old male patient, a rare anatomic variant was found to be associated with a previously unreported one. Both ACAs had symmetrical horizontal and vertical segments, but the AComA was absent from the usual location. The right ACA continued as CMA without sending off a pericallosal artery. A median artery of corpus callosum (MACC) left from the horizontal segment of the left ACA. Then the left ACA continued as CMA. At 1.9 cm from its origin, the MACC was united to the right CMA by a high, interhemispheric AComA. Therefore, an AComA should be regarded as absent only after documenting the bilateral anastomoses within the interhemispheric fissure. A third interhemispheric main artery, such as a rarely occurring MACC, could be accurately documented by computed tomography angiogram to avoid unpleasant intraoperative hemorrhage or to establish a personalized endovascular route to the anterior cerebral system.

Cerebral monitoring of very preterm infants with anterior cerebral artery resistive index and early NIRS.

BACKGROUND: The prediction of adverse conditions in the preterm neonatal brain might be improved by cerebral monitoring using combined measures of cerebral function, including oxygenation and blood flow parameters. To perform the consecutive measurements of the resistive index (RI) from the anterior cerebral artery (ACA) within the first week of life and to evaluate the association of these measurements with cerebral oxygen saturation (Csat) detected by near-infrared spectroscopy (NIRS). METHODS: This prospective cohort study enrolled very preterm infants, <32 weeks of gestational age, admitted to a tertiary neonatal intensive care unit. Csat levels were continuously monitored using NIRS for 72 h after birth. ACA RI measurements were obtained on the first, third, and seventh days of life by using transcranial Doppler ultrasound. These measurements were also compared between infants with and without unfavorable outcomes, including severe intraventricular hemorrhage (IVH) and early mortality. RESULTS: A total of 96 preterm infants with Csat and ACA RI measurements were analyzed. Age at birth was 28.3 ± 1.9 weeks and birth weight was 1090 ± 305 g. The mean Csat of the infants was 77.1% ± 8.2% during the first 72 h of life. Mean ACA RI values were 0.76 ± 0.10, 0.75 ± 0.08, and 0.77 ± 0.08 on the first, third, and seventh days of life, respectively. RI on the first day of life was significantly higher in infants delivered by cesarian section than in those delivered vaginally (0.77 vs. 0.69; p = 0.017). Infants who died earlier had significantly higher ACA RI values on the first day than infants who survived beyond the first 7 postnatal days (0.83 vs. 0.76; p < 0.001). DISCUSSION: There was no association between ACA RI and Csat in the early period of life. ACA RI values on the first postnatal day might be significant for predicting early mortality in very preterm infants.

Single-lane clipping technique for a ruptured aneurysm of A1 fenestration of the anterior cerebral artery: a case report and literature review.

Fenestration of the A1 segment of the anterior cerebral artery is a rare vascular anomaly with a high risk of saccular aneurysm at the proximal end of the A1 fenestration. These aneurysms have a high risk of rupture. However, conventional surgical clipping can be technically challenging due to the anatomical characteristics. We report a case of A1 fenestration with a ruptured aneurysm wherein we successfully achieved complete obliteration of the aneurysm with a new "single-lane" clipping technique. A 64-year-old woman presented with a ruptured saccular A1 aneurysm at the proximal end of an A1 fenestration, resulting in subarachnoid hemorrhage. Microsurgical clipping was attempted; however, adequate exposure of the aneurysm could not be achieved. The recurrent artery of Heubner originated near the distal end of the lateral limb of the A1 fenestration. The lateral limb of the A1 fenestration had no perforating arteries, according to surgical examination. Thus, the aneurysm neck and lateral limb were concurrently obliterated using a nonfenestrated clip, preserving the medial limb of the A1 fenestration. The antegrade flow of the recurrent artery of Heubner was detected using the retrograde flow of the distal part of the lateral limb of the A1 fenestration during intraoperative indocyanine green video angiography. The postoperative course was uneventful without any evidence of ischemic stroke. For A1 aneurysms arising from the proximal end of the A1 fenestration, this technique may be a useful treatment option. Before using this technique, careful surgical exploration should be performed to assess the A1 perforating arteries.

Risk factors for the rupture of anterior communicating artery aneurysms: Coexistence of fetal-type posterior cerebral artery and A1 segment hypoplasia/agenesis.

PURPOSE: To investigate the effect of the coexistence of fetal-type posterior communicating artery (fPCA) and anterior cerebral artery (ACA) A1 segment agenesis/hypoplasia on the rupture of an anterior communicating artery (AComA) aneurysm. MATERIALS AND METHODS: A total of 216 patients consecutively presenting with AComA aneurysms between January 2014 and December 2021 on digital subtraction angiography were evaluated. Patients without three-dimensional rotational angiography images, those aged under 18 years, those with suspected mycotic aneurysms, and those with dissecting and giant aneurysms were excluded from the study. The aneurysms were divided into two groups as ruptured and non-ruptured. Hemodynamic filling patterns were classified into four different types. RESULTS: The study included 192 AComA aneurysms, 44.8% (n = 86) ruptured and 55.2% (n = 106) non-ruptured. According to hemodynamic filling patterns, in type 1, the frequency of non-ruptured aneurysms was statistically significantly higher than that of ruptured aneurysms (39.5% vs 18.9%; p = 0.001). In type 4, where fPCA and ACA A1 segment agenesis/hypoplasia coexists, the frequency of ruptured aneurysms was significantly higher than that of non-ruptured aneurysms (10.5% vs 22.7%; p = 0.026). The most common aneurysm size range was 4-7 mm (n = 85; 44.3%). There was no statistically significant difference in size between the ruptured and non-ruptured aneurysms (p = 0.627). CONCLUSION: According to the hemodynamic filling classification, we observed that the presence of type 4 filling pattern, i.e., the coexistence of ACA A1 segment agenesis/hypoplasia and fPCA, increased the risk of rupture in AComA aneurysms.

Microsurgical anatomy of the anterior cerebral artery and the arterial supply of the cingulate gyrus.

PURPOSE: The cingulate gyrus is a potential surgical area to treat tumours, psychiatric diseases, intractable pain and vascular malformations. The aim of the study was to define the topographic anatomy and arterial supply of the cingulate gyrus located on the medial surface of the cerebral hemisphere. METHODS: We studied thirty-six hemispheres, each hemisected in the midsagittal plane. The vertical thickness of the cingulate gyrus was measured at the anterior commissure (AC), posterior commissure (PC), and genu levels of the corpus callosum. The branches of the anterior and posterior cerebral arteries supplying each zone were noted separately. The arterial pathways were transformed to digital data in AutoCAD to identify the condensation and reduction areas. RESULTS: The mean AC-PC distance was 27.17 ± 1.63 mm. The thinnest region was the genu level of the corpus callosum (10.29 mm). The superior internal parietal artery (SIPA), inferior internal parietal artery (IIPA) and pericallosal artery (PrCA) supplied all zones of the cingulate gyrus. The anterior zone received the greatest supply. The arterial condensation and reduction areas on both sides of cingulate gyrus and its x, y, and z coordinates specified. CONCLUSIONS: The target cingulotomy (TC) area was determined for anterior cingulotomy. The properties of the TC area are that the thinnest region of the cingulate gyrus is supplied relatively less than other areas and is close to the anterior cingulotomy areas in the literature. The arterial reduction area (ARA) was found to be suitable for corpus callosotomy in terms of avoiding haemorrhage.

Small symptomatic anterior communicating artery aneurysms: report of three cases and literature review.

PURPOSE: Given the anatomical relationship between the ACom complex and the optic nerve, small aneurysms of the ACom can present with visual symptoms. CASE REPORTS: We summarize and illustrate the clinical course of three patients with symptomatic small ACom aneurysms and collect similar other cases reported. RESULTS: Ten patients with small unruptured visually symptomatic anterior communicating artery aneurysms were found in the literature. Including three patients herein reported, the mean age at presentation was 56. The most common visual symptoms were bitemporal vision loss and/or a decrease in visual acuity. CONCLUSION: Unruptured aneurysms of the anterior communicating artery can present with visual symptoms due to compression of optic pathways, even at a small size. Prompt recognition and treatment of such a condition are paramount as new onset of visual symptoms can signify impending rupture akin to small PCom aneurysms compressing the third nerve. We discuss a few pitfalls of clipping small ACom aneurysms compressing the optic nerve.

Aberrant Origin of the Distal Anterior Cerebral Artery from the Middle Cerebral Artery Related to Obstruction of Bilateral Proximal Anterior Cerebral Arteries: A Case Report.

BACKGROUND: Aberrant origin of the distal anterior cerebral artery (ACA) arising from the middle cerebral artery (MCA) is extremely rare. CASE PRESENTATION: A 74-year-old woman with a sudden onset of left-sided weakness was admitted to the emergency department. Angiography revealed an unusual course of the distal ACA originating from the MCA with bilateral obstruction of the proximal segment of the ACA and simultaneous occurrence of infarction in the ACA and MCA territories. CONCLUSION: Knowledge of a rare vascular variation or anomaly could help understand brain imaging, which has an unusual involvement of vascular territories, performed in patients with acute ischemic stroke.