Anterior Communicating Artery Complex Research Articles

Trend of cerebral aneurysms over the past two centuries: need for early screening

ObjectiveCerebral aneurysms (CAs) are linked to variations in the cerebral basal arterial network (CBAN). This study aimed to find the optimal age for screening to detect brain arterial variations and...

Anatomical Variations and Anomalies of the Anterior Communicating Artery Complex

INTRODUCTIONIntracranial 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. MATERIAL AND 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. The variations were then schematically drawn. The surgical view during pterional craniotomy and transsylvian approach was used as a baseline. RESULTS: A total of 42 variants were identified and schematically drawn and classified into A1 / A2 segment, anterior communicating artery and the recurrent artery of Heubner. CONCLUSION: In this review we classify and depict all variations and anomalies within the Anterior Communicating Artery Complex. Anatomical knowledge of this region is of utmost importance during microsurgical clipping to prevent complications. This overview could prove useful in both microsurgical and endovascular management of patients with aneurysms of the anterior communicating artery.

Importance of Preoperative Vertical Geometric Analysis in Surgery for Anterior Communicating Artery Aneurysm.

In this study, we analyzed the vertical geometry of the anterior communicating artery (AComA) complex with the aim to improve the surgical site orientation during aneurysm operations. Further, the geometric data that can contribute to the success of the surgical technique applied for AComA aneurysms are reported. Computed tomography angiography data of the cerebral arteries of 100 patients who visited our clinic were analyzed. A three-dimensional examination was performed according to the Frankfurt horizontal plane (FHP) using the RadiAnt DICOM Viewer (Medixant, Poznan, Poland), and vertical measurements of the AComA complex were calculated. The Willis polygon values were found to be consistent with those in the literature. The mean height of the AComA complex was 30.58 ± 4.80 mm according to the FHP. Preoperative evaluation of the vertical geometry of the AComA complex is essential for AComA aneurysm surgery. The height of the AComA complex is a key parameter affecting intraoperative surgical site visibility. Preoperative calculation of the height of the AComA complex relative to FHP can facilitate intraoperative surgical site orientation.

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.

Letter to the Editor Regarding “Clinical Utility of Routine Postprocedural Computed Tomography of the Head Following Elective Neuroendovascular Interventions”

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.

FRED Jr stent for acute flow diversion in ruptured cerebral aneurysms arising from small-caliber vessels: a clinical case series.

Treatment of ruptured aneurysms arising from small-caliber (< 2.5 mm) or distal vessels beyond the circle of Willis is considered challenging with all treatment modalities. Recently, the Flow Re-Direction Endoluminal Device Junior (FRED Jr) stent, designed for flow diversion in small arteries, was approved in the United States for the treatment of nonruptured aneurysms. Here, the authors report their experience using this device in the setting of subarachnoid hemorrhage (SAH). Clinical and radiological records of patients sustaining SAH treated with a FRED Jr stent between June 2020 and October 2022 were reviewed. Treatment course, including antiplatelet therapy, external ventricular drain (EVD) management, and vasospasm, and clinical outcomes were analyzed. Angiographic results were assessed according to the O'Kelly-Marotta (OKM) grading scale. Nine patients at a median age of 62 (range 27-75) years were included. The median Hunt and Hess grade was II (IQR I) and the median modified Fisher grade was 4 (IQR 1). Aneurysm morphology types included saccular (6 patients), blister (1 patient), and dissecting (2 patients), and the aneurysms were located at the anterior communicating artery complex (n = 3) at the A2/A3 (n = 3), M2/M3 (n = 1), V4 (n = 1), and P2 (n = 1) arterial segments. All stents were deployed successfully with no intraprocedural complications. Postoperatively, no rebleeding events were encountered. Vasospasm therapy was initiated in 6 patients, and no symptomatic EVD-related hematomas were observed. Postoperative ischemic events were encountered in 2 patients. The median 3-month modified Rankin Scale score was 2 (IQR 1) for the 7 surviving patients, and 3-month radiographic follow-up revealed OKM grade D in 4 of 7 patients. Flow diversion using the FRED Jr stent is feasible as a potential treatment strategy for acutely ruptured aneurysms arising from small-caliber vessels. The complication profile reported in this series is comparable to those of historical microsurgical cohorts, and effective protection was conferred by this treatment modality. Therefore, our small cohort provides a glimpse into a new tool for successfully achieving acute flow diversion for this subset of difficult-to-treat aneurysms.

IMAGING OF THE ANTERIOR COMMUNICATING ARTERY: NORMAL AND ABNORMAL FINDINGS RELATED TO ANEURYSM

The anterior communicating artery (AComA) is a critical component of the Circle of Willis, serving as a vital conduit that connects the bilateral anterior cerebral arteries. This study aims to provide a comprehensive overview of the imaging characteristics of the AComA, encompassing both normal variations and abnormal findings associated with aneurysm development. Utilizing advanced imaging techniques, a thorough analysis of the AComA complex was conducted in a cohort of subjects. Normal anatomical variants were meticulously documented, highlighting variations in length, diameter, and branching patterns. Abnormal findings indicative of potential aneurysm markers was carefully assessed, encompassing variations in morphology, hemodynamic flow patterns, and wall integrity. Special attention was given to elucidate the factors contributing to aneurysm initiation within the AComA complex. The clinical significance of distinguishing between normal anatomical variations and potential pathological findings was underscored, emphasizing the critical importance of early detection and intervention to mitigate the risks associated with aneurysm rupture. The findings of this study contribute valuable insights to the field of neurovascular diagnostics and therapeutic strategies. By enhancing our understanding of the AComA and its role in aneurysm development, this research aims to empower clinicians with the knowledge needed for informed decision-making and proactive management. Ultimately, the comprehensive examination of AComA imaging, encompassing both normal and abnormal variants, holds the potential to drive advancements in cerebrovascular care and improve patient outcomes.

The risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms: anatomical consideration and infarction territory.

An anterior communicating artery is a common location for both ruptured and unruptured intracranial aneurysms, and microsurgery is sometimes necessary for their successful treatment. However, postoperative infarction should be considered during clipping due to the complex surrounding structures of anterior communicating artery aneurysms. This study aimed to evaluate the risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms and its clinical outcomes. The data of patients who underwent microsurgical clipping of an unruptured anterior communicating artery aneurysm in our hospital between January 2008 and December 2020 were retrospectively analyzed. The patients' demographic data, anatomical features of the anterior communicating artery complex and aneurysm, surgical technique, characteristics of postoperative infarction, and its clinical course were evaluated. Notably, among 848 patients, 66 (7.8%) and 34 (4%) patients had radiologic and symptomatic infarctions, respectively. Univariate and multivariate logistic regression analyses showed that hypertension (odds ratio (OR), 1.99; [Formula: see text]), previous stroke (OR, 3.89; [Formula: see text]), posterior projection (OR, 5.58; [Formula: see text]), aneurysm size (OR, 1.17; optimal cut-off value, 6.14mm; [Formula: see text]), and skull base-to-aneurysm distance (OR, 1.15; optimal cut-off value, 11.09mm; [Formula: see text]) were associated with postoperative infarction. In the pterional approach, a closed A2 plane was an additional risk factor (OR, 1.88; [Formula: see text]). Infarction of the subcallosal and hypothalamic branches was significantly associated with symptomatic infarction ([Formula: see text]). Hypertension, previous stroke, posteriorly projecting aneurysms, aneurysm size, and highly positioned aneurysms are independent risk factors for postoperative infarction during surgical clipping of an unruptured anterior communicating artery aneurysm. Additionally, a closed A2 plane is an additional risk factor of postoperative infarction in patients undergoing clipping via the pterional approach.

Magnetic Resonance Angiographic Study of the Anatomical Variations of the Anterior Communicating Artery Complex in a Turkish Population.

To provide a definition of arterial anomalies in the anterior communicating artery complex (ACoAC), determine their prevalence and investigate their relationship with aneurysms. The three-dimensional time-of-flight magnetic resonance angiography images of 1,857 adult patients who presented to our hospital between January 2020 and September 2022 were evaluated retrospectively. The images of 1,537 cases were subsequently classified according to their ACoAC anatomical variants. The patients were further grouped as those with no pathology, those with ACoAC aneurysms and those with pathologies other than ACoAC, and the relationship between the ACoAC anatomical variants of each group was investigated using statistical methods. Rare variants such as trifurcations of the A2 segments, single A2 segments, fenestrations of the A1 segment and double AComAs were evaluated in separate groups. The results of the classification of the 1,537 cases revealed the classical anatomical variant in 39.2% of the cases without ACoAC pathologies and 53.3% of the cases with ACoAC aneurysms. There was no significant difference between the sexes in terms of variant distribution (p=0.09), and no significant relationship between the presence of ACoAC aneurysms and sex (p=0.5). ACoAC anatomical variants of the cerebral arterial system were detected in 60% of the cases. The most common anterior circulation (AC) vascular variants (VV) were A1 segment hypoplasia and aplasia. No clear relationship was found between intracranial aneurysms and anatomical variation.

Flow Diverter Devices in the Treatment of Anterior Communicating Artery Region Aneurysms: Would the Regional Anatomy and the Aneurysm Location Affect the Outcomes?

In this study, the authors evaluated the efficacy and the safety of flow diverter devices (FDD) in anterior communicating artery (ACoA) region aneurysms, focusing on anatomical factors that could affect the outcome, such as the location of the aneurysm along the ACoA (centered on ACoA or decentered on the A1-A2 junction) and the anatomy of the ACoA region. Clinical, procedural and follow-up data were analyzed. Aneurysms were classified according to the location along the ACoA (centered or decentered on the A1-A2 junction) and on the basis of the anatomical configuration of the ACoA region. Safety was assessed by recording intraprocedural, periprocedural and delayed complications to determine the morbidity and mortality rates. The functional outcome was evaluated with the modified Rankin scale (mRS) prior to and after the endovascular procedure. To assess the efficacy, midterm and long-term clinical, angiographic and cross-sectional imaging follow-ups were recorded. Subgroup analysis according to the different ACoA regional anatomical configurations and the ACoA aneurysm locations were performed. 33 patients (17 males; 16 females) with ACoA region aneurysms were treated with FDDs. 27 aneurysms were located at the A1-A2 junction (82%) while the remaining six aneurysms were centered on the ACoA. No mortality was recorded. The overall morbidity rate was 6% (2/33 procedures). Major complications occurred in 33% (2/6) of ACoA aneurysms and in the 0% of A1-A2 junction aneurysms. Mid-term and long-term neuroimaging follow-ups showed the occlusion of the aneurysm in 28/33 cases (85%). Complete occlusion rates were 93% in the A1-A2 junction aneurysms and 50% in ACoA aneurysms. The FDD is a safe and effective tool that can be used in the treatment of selected cases of ACoA region aneurysms. The location of the aneurysm along the ACoA and the regional anatomy of the ACoA complex could affect the efficacy and safety.

Rupture pressure values of cerebral arteries in the presence of unruptured intracranial aneurysm

Cerebral arteries (CAs) are prone to the saccular aneurysm formation. Since aneurysms may be considered as balloon-like dilations of the locally weakened arterial wall, it should be determined whether the presence of intracranial aneurysm is related to the generalized weakening of CAs. Among 184 consecutive forensic autopsies, eight brains with a single unruptured saccular aneurysm were identified. Aneurysms with adjacent CAs and specific CA segments were excised, namely: the anterior communicating artery complex, and bifurcations of the basilar artery, internal carotid arteries, and middle cerebral arteries. Then, aneurysm and CA specimens were subjected to pressure-inflation tests until rupture occurred at the arterial bifurcation or at the wall of the CA or aneurysm. The same protocol was applied to the control group composed of CAs excised from eight brains without aneurysm. No significant differences were noted between the experimental and control groups, depending on the mean rupture pressure (1054 vs. 1048 mmHg) and rupture site (bifurcation vs. wall) of the analyzed specimens. These findings indicate that the presence of unruptured saccular aneurysm is not related to generalized weakening of CAs among autopsy subjects. Moreover, the CA bifurcations do not represent regions of decreased wall strength.

Aneurysm presence at the anterior communicating artery bifurcation is associated with caliber tapering of the A1 segment.

Vessel tapering results in blood flow acceleration at downstream bifurcations (firehose nozzle effect), induces hemodynamics predisposing to aneurysm initiation, and has been associated with middle cerebral artery (MCA) aneurysm presence and rupture status. The authors sought to determine if vessel caliber tapering is a generalizable predisposing factor by evaluating upstream A1 segment profiles in association with aneurysm presence in the anterior communicating artery (ACoA) complex, the most prevalent cerebral aneurysm location associated with a high rupture risk. Three-dimensional rotational angiographic studies were analyzed for 68 patients with ACoA aneurysms, 37 nonaneurysmal contralaterals, and 53 healthy bilateral controls (211 samples total). A1 segments were determined to be dominant, codominant, or nondominant based on flow and size. Equidistant cross-sectional orthogonal cuts were generated along the A1 centerline, and cross-sectional area (CSA) was evaluated proximally and distally, using intensity-invariant edge detection filtering. The relative tapering of the A1 segment was evaluated as the tapering ratio (distal/proximal CSA). Computational fluid dynamics was simulated on ACoA parametric models with and without tapering. Aneurysms occurred predominantly on dominant (79%) and codominant (17%) A1 segments. A1 segments leading to unruptured ACoA aneurysms had significantly greater tapering compared to nonaneurysmal contralaterals (0.69 ± 0.13 vs 0.80 ± 0.17, p = 0.001) and healthy controls (0.69 ± 0.13 vs 0.83 ± 0.16, p < 0.001), regardless of dominance labeling. There was no statistically significant difference in tapering values between contralateral A1 and healthy A1 controls (0.80 ± 0.17 vs 0.83 ± 0.16, p = 0.56). Hemodynamically, A1 segment tapering induces high focal pressure, high wall shear stress, and high velocity at the ACoA bifurcation. Aneurysmal, but not contralateral or healthy control, A1 segments demonstrated significant progressive vascular tapering, which is associated with aneurysmogenic hemodynamic conditions at the ACoA complex. Demonstration of the upstream tapering effect in the communicating ACoA segment is consistent with its prior detection in the noncommunicating MCA bifurcation, which together form more than 50% of intracranial aneurysms. The mechanistic characterization of this upstream vascular tapering phenomenon is warranted to understand its clinical relevance and devise potential therapeutic strategies.

Disturbances of cerebrospinal fluid dynamics as a complication of aneurysmal subarachnoid hemorrhage: predictors of development and influence of aneurysm occlusion method on the development of shunt-dependent hydrocephalus

Objective ‒ to study the effect of ruptured aneurysm localization, severity of hemorrhage and aneurysm occlusion method on the probability of developing shunt-dependent hydrocephalus (SDH) and to assess the prognostic sensitivity of clinical and radiological scales.Materials and methods. The results of treatment of 597 patients with aneurysmal subarachnoid hemorrhage (SAH) of varying severity were analyzed. In 282 cases endovascular occlusion of the aneurysm was performed, in 315 ‒ microsurgical clipping. A group of 63 patients who required implantation of the ventriculoperitoneal shunt system within 3 to 15 weeks after aneurysm rupture was selected.Results. Of the patients who underwent coiling of the ruptured aneurysm, 22 (7.8 %) required implantation of the cerebrospinal fluid shunt system, and 41 (13.0 %) of the patients who underwent microsurgery. The mean age of patients in the endovascular occlusion group was 64.28 years, in the microsurgical clipping group ‒ 50.64 years. The localization was dominated by aneurysms of the anterior communicating artery (ACA) complex ‒ 37 (58.7 %) observations, internal carotid artery ‒ 15 (23.8 %), vertebrobasilar basin (VBB) ‒ 9 (14.3 %) and the middle cerebral artery ‒ 2 (3.2 %). The predominance of aneurysms of the ACA complex among those operated by microsurgical method (29 (70.7 %)) and VBB aneurysms among those operated on endovascularly (9 (40.9 %)) was revealed. Rupture of the aneurysm was complicated by massive SAH in 20 (31.7 %) cases, subarachnoid-parenchymal hemorrhage ‒ in 7 (11.1 %), subarachnoid-ventricular ‒ in 4 (6.4 %), subarachnoid-parenchymal-ventricular ‒ in 32 (50.8 %). The distribution by severity of hemorrhage on the Hunt‒Hess scale was as follows: grade II ‒ 10 (15.9 %) cases, grade III ‒ 26 (34.9 %), grade IV ‒ 27 (49.2 %). According to the Fisher radiological scale, grade III hemorrhage was noted in 20 (31.7 %) cases, IV ‒ in 43 (68.3 %) cases. Analysis using the Graeb scale showed the absence of blood in the ventricular system in 27 (42.9 %) cases, 1‒3 points ‒ in 9 (14.3 %), 4‒6 points ‒ in 12 (19.0 %), 7–12 points ‒ in 15 (28.8 %).Conclusions. Rupture of aneurysms of the ACA complex, accompanied by severe complicated SAH in patients operated on by microsurgery, and aneurysms of the VBB in persons operated on endovascularly, increases the risk of SDH. Endovascular occlusion of ruptured aneurysms does not increase the risk of SDH. The severity of hemorrhages of III–IV degree on the Hunt‒Hess scale and III–IV degree on the Fisher scale are predictors of SDH development.

Vascular Anatomy of Anterior Communicating Artery Complex for Microsurgery

Vascular Anatomy of Anterior Communicating Artery Complex for Microsurgery

Microsurgery for Multiple Intracranial Aneurysms

Background: A total of 23 patients with 52 aneurysms were surgically treated in single surgery at a Neurosurgical Service of the Health Service of the State of São Paulo from 2009 to 2011. Method: Retrospective analysis of patients undergoing clipping of two or more cerebral aneurysms in a single stage, from January 2007 to July 2012. Results: Twenty-nine patients underwent two or more clipping cerebral aneurysms in a single surgery – 28 with a single craniotomy and one through two craniotomies. Of these, 20, 7, 1 and 1 were submitted to the clipping of 2, 3, 4 and 5 cerebral aneurysms, respectively. Five were male and 24 were female, and the age range was 40 to 66-years-old. Eight left craniotomies were performed to approach 17 lateralized brain aneurysms to the left and five to the right, as well as three anterior communicating complex aneurysms. Twelve craniotomies were performed on the right to approach 23 intracranial aneurysms lateralized to the right and six on the left, as well as 15 anterior communicating artery complex aneurysms and 1 on the basilar artery. Of the 29 patients, 28 evolved with 1-3 pts and only one with 4-5 pts on the Rankin scale, six months after surgery. Conclusion: We advocate microsurgical approach for most of the cases of multiple intracranial aneurysms aiming the microsurgical clipping of all intracranial aneurysms if feasible through a single stage and a single craniotomy.

Anterior Communicating Artery Complex Anatomy and its Correlation with Aneurysm Formation

Anterior Communicating Artery Complex Anatomy and its Correlation with Aneurysm Formation

Relationship between cerebral aneurysms and variations in cerebral basal arterial network: a morphometric cross-sectional study in Computed Tomography Angiograms from a neurointerventional unit

ObjectiveSegments of cerebral basal arterial network (CBAN) dampen the peak pressure in blood flowing through these arteries, thus minimising the chances of development of cerebral aneurysms. The objective of this...

Impact of subcallosal artery origin and A1 asymmetry on surgical outcomes of anterior communicating artery aneurysms.

Surgical clipping of anterior communicating artery (ACoA) aneurysms remains challenging due to their complex anatomy. Anatomical risk factors for ACoA aneurysm surgery require further elucidation. The aim of this study is to investigate whether proximity of the midline perforating artery, subcallosal artery (SubCA), and associated anomaly of the ACoA complex affect functional outcomes of ACoA aneurysm surgery. A total of 92 patients with both unruptured and ruptured ACoA aneurysms, who underwent surgical clipping, were retrospectively analyzed from a multicenter, observational cohort database. Association of ACoA anatomy with SubCA origin at the aneurysmal neck under microsurgical observation was analyzed in the interhemispheric approach subgroup (n = 56). Then, we evaluated whether anatomical factors associated with SubCA neck origin affected surgical outcomes in the entire cohort (both interhemispheric and pterional approaches, n = 92). In the interhemispheric approach cohort, combination of A1 asymmetry and aneurysmal size ≥ 5.0mm was stratified to have the highest probability of the SubCA neck origin by a decision tree analysis. Then, among the entire cohort using either interhemispheric or pterional approach, combination of A1 asymmetry and aneurysmal size ≥ 5.0mm was significantly associated with poor functional outcomes by multivariable logistic regression analysis (OR 6.76; 95% CI 1.19-38.5; p = 0.03) as compared with A1 symmetry group in the acute subarachnoid hemorrhage settings. Combination of A1 asymmetry and larger aneurysmal size was significantly associated with SubCA aneurysmal neck origin and poor functional outcomes in ACoA aneurysm surgery. Interhemispheric approach may be proposed to provide a wider and unobstructed view of SubCA for ACoA aneurysms with this high-risk anatomical variant.

A study of the anatomical variations in branching pattern of middle cerebral artery

Middle cerebral artery (MCA) is the largest and most complex arterial system of the brain. Variations of the aortic arch branches are due to alteration in the development of specific branchial arch arteries during the embryonic period. Knowledge of these variations is important during aortic instrumentation, thoracic, and neck surgeries. The anatomy of the anterior cerebral artery branches and the anterior communicating artery complex needs to be investigated individually to minimise neurovascular morbidity before iatrogenic procedures. The study aimed to study the variations in the microsurgical anatomy of the MCA in our population and compare the variables and discuss their importance with anatomic and surgical considerations. Specimens were collected from the embalmed cadavers and the post-mortem bodies in the department of forensic medicine of Thanjavur Medical College. The different variables regarding the MCA in our population were analysed and compared with the studies in the Western population and other Indian studies. The mean length of the MCA in this study was 12.8 mm with a standard error of 3.79 mm. The outer diameter of the M1 segment was with a mean length of 3.75mm. In 69.2% middle, Cerebral Artery shows bifurcation and in 20%, it shows trifurcation and in 10.8%, it shows ramification types of branching patterns. The 39.1% cases show Temporo polar, 21.7% orbitofrontal, 9.1% anterior temporal, 6.6% prefrontal, and 4.1% middle temporal branches. Our results also reveal that the origin of the lenticulostriate branch in the middle cerebral artery was 85.85% from the trunk and 14.2% from division, respectively. MCA branching pattern is slightly higher in trifurcation pattern as compared to bifurcation and ramification. Thorough knowledge of the microvascular anatomy and the myriads of variations is essential for the operating surgeon to choose the ideal technique to avoid any catastrophe during and after surgery and give the best possible functional outcome.

An MRI study of typical anatomical variants of the anterior communicating artery complex.

This magnetic resonance imaging study examined the most frequent anatomical variants of the anterior communicating artery (ACoA) complex of the cerebral arterial circle, and aimed to determine whether they were associated with ACoA complex aneurysm. The study enrolled 669 patients. Using three-dimensional time-of-flight magnetic resonance angiography, 617 patients were classified into the following groups based on the anatomical variation in the ACoA complex: no ACoA complex anomaly; ACoA complex aneurysm; and vascular anomaly distant from the cerebral arterial circle. Of the 617 classified subjects, the classical anatomical description applied to 48.73% in the no ACoA complex anomaly group and 37.5% in the ACoA complex aneurysm group. One variant (left anterior cerebral artery segment A1 hypoplasia) was significantly more frequent in the ACoA complex aneurysm group. There was no sex difference in the prevalence of any variant. Anatomical variants of the ACoA complex of the cerebral arterial circle were found in almost half of the subjects. One variant seemed to be associated with a higher likelihood of an aneurysm, but causality could not be inferred.