A1 Segment Of Anterior Cerebral Artery Research Articles

Circulus Willis Anomalies Diagnosed with CT Angiography and Evaluation of Their Relations with Ischemic Stroke

Our aim in this study is examining the frequency of posterior communicating artery (PCoM), Anterior Cerebral Artery A1 segment (ACA AI) and Fetal type posterior cerebral artery (FPCA) anomalies and their effects on ischemic stroke by retrospectively analyzing examinations of Computerized Tomography Angiography (CTA) taken in our hospital within 2017. 22 cases (26.5%) diagnosed with bilateral hypoplastic / aplastic PCoA anomaly, were diagnosed with anterior circulation infarct, 24 cases (28.9%) were diagnosed with posterior circulation infarct, but 37 cases (44.6%) were not diagnosed with ischemic stroke. 17 (37.8%) of the cases who have unilateral hypoplastic / aplastic PCoA anomaly, were diagnosed with anterior circulation infarct, 14 cases (31.1%) were diagnosed with posterior circulation infarct. 13 (26%) of 50 cases diagnosed with unilateral hypoplastic / aplastic ACA A1 segment, were diagnosed with anterior circulation infarct, 10 cases (20%) were diagnosed with posterior circulation infarct. 27 cases (54%) were not diagnosed with ischemic stroke. Both of 2 cases diagnosed with bilateral hypoplastic / aplastic ACA A1 segment, had anterior circulation infarct. 4 (30.8%) of 13 cases diagnosed with unilateral FPCA anomaly, were diagnosed with anterior circulation infarct, 3 cases (23.1%) were diagnosed with posterior circulation infarct, 6 cases (46.2%) did not have ischemic stroke symptoms. In conclusion, even though these variations’ role in optimum stroke prophylaxis in individuals having one or more stroke risk factors, has not determined yet, there is no doubt that clinical researcher will eliminate these uncertainties in future studies.

Proximal Clipping and Distal High-Flow Bypass in the Treatment of Giant/Complex Intracranial Aneurysm: An Opportunity or a Risk from a Fluid-Structural Interaction Analysis.

Conventional clipping and endovascular treatment are difficult to apply for some giant intracranial aneurysms (GIAs), and sometimes extracranial-to-intracranial (EC-IC) bypass becomes the optional choice. However, not all GIA patients can benefit from it. This study aims to recognize the underlying problems. We included eligible patients in our care. Then, we researched from three levels: a retrospective review of clinical data, fluid-structural analysis from two representative patient-specific models, and fluid-structural interaction analysis for idealized models to investigate the hemodynamic and biomechanical mechanisms. In this article, we report nine patients with GIA who underwent EC-IC surgery. Of them, three experienced dangerous postoperative hemorrhage, and one patient died. Among these three patients, two lacked the A1 segment of the anterior cerebral artery (ACA). The numerical simulation showed that after surgery, for the patient with an unruptured aneurysm and existence of ACA, the wall deformation, wall stress, pressure, and area of the oscillatory shear index (OSI) > 0.2 were decreased by 43%, 39%, 33%, and 13%, while the patient without A1 segment having postoperative hemorrhage showed 36%, 45%, 13%, and 55% increased, respectively. Thus, we postulated a dangerous "stump phenomenon" in such conditions and further demonstrated it from idealized models with different sizes of ACA. Finally, we found a larger anastomosis angle and smaller diameter of the graft can alleviate this effect. Neurosurgeon should cautiously evaluate the opportunity and risk for such patients who have aplasia of the A1 segment of ACA when making clinical decisions.

Internal carotid artery stenosis: hemodynamics in the ipsilateral ACA affects CT angiography manifestations.

This study aimed to evaluate whether CT angiography (CTA) manifestations in anterior cerebral artery a1 segment (A1) were related to the hemodynamics in patients with internal carotid artery stenosis (ICAS). A total of 97 cases were selected. The degree of ICAS and symmetry of A1 were evaluated by CTA examination. Hemodynamic indexes were detected by transcranial Doppler (TCD). The differences in CTA presentations of A1 and hemodynamics between the vessels on the stenotic and contralateral sides were analyzed according to the different degrees of stenosis. The degree of ICAS according to the different manifestations of A1 and the hemodynamics of A1's adjacent vessels were also analyzed. In the case of unilateral ICAS, the difference in Vm of A1 between the stenotic and the contralateral side was the most significant relative to the stenosis degree. When unilateral ICAS was ≥70%, the presentation of A1 on the stenotic side was more slender or non-visualized compared to that on the contralateral side, while in cases with unilateral stenosis <70% or bilateral stenosis with a similar degree of stenosis, A1 were mainly symmetrical. When A1 on the side of ICAS was slender or non-visualized, the Vm of A1 was significantly slower than that on the contralateral side (P < 0.001). The CTA manifestations of A1 on the side of ICAS embodied the overall changes of the intracranial hemodynamics after ICAS. A combination of TCD and CTA examination of A1 can assist in judging the location and degree of ICAS.

Hemodynamic characteristics and mechanism for intracranial aneurysms initiation with the circle of Willis anomaly

Clinically, circle of Willis (CoW) is prone to anomaly and is also the predominant incidence site of intracranial aneurysms (IAs). This study aims to investigate the hemodynamic characteristics of CoW anomaly, and ascertain the mechanism of IAs initiation from the perspective of hemodynamics. Thus, the flow of IAs and pre-IAs were analyzed for one type of cerebral artery anomaly, that is, anterior cerebral artery A1 segment (ACA-A1) unilateral absence. Three patient geometrical models with IAs were selected from Emory University Open Source Data Center. IAs were virtually removed from the geometrical models to simulate the pre-IAs geometry. For calculation methods, a one-dimensional (1-D) solver and a three-dimensional (3-D) solver were combined to obtain the hemodynamic characteristics. The numerical simulation revealed that the average flow of Anterior Communicating Artery (ACoA) is almost zero when CoW is complete. In contrast, ACoA flow increases significantly in the case of ACA-A1 unilateral absence. For per-IAs geometry, the jet flow is found at the bifurcation between contralateral ACA-A1 and ACoA, which exhibits characteristics of high Wall Shear Stress (WSS) and high wall pressure in the impact region. It triggers the initiation of IAs from the perspective of hemodynamics. The vascular anomaly that leads to jet flow should be considered as a risk factor for IAs initiation.

Abstract Number: LBA7 Outcomes of Endovascular Thrombectomy Versus Medical Treatment in Ischemic Strokes Secondary to Medium Vessel Occlusion

Introduction Acute ischemic stroke (AIS) from arterial occlusions are treated with emergent endovascular thrombectomy (EVT) when clinically appropriate. Clinical outcomes of EVT in medium vessel occlusion (MVO) compared to large vessel occlusion (LVO) have neither been well established nor compared to alternate medical management. Our aim was to evaluate outcomes of patients with AIS secondary to MVO undergoing EVT. Methods We conducted a retrospective chart review of patients presenting to our comprehensive stroke center with MVO‐associated AIS undergoing EVT or aggressive intra‐arterial thrombolytic treatment with concurrent administration of IV eptifibatide. We assessed occlusion site, NIHSS (presentation, 7 day or discharge, 3 months), modified Rankin Scale (baseline, 90‐day), and intracranial hemorrhage (ICH) rate. MVO was defined as occlusion of pure M2 middle cerebral artery without M1 segment involvement, anterior cerebral artery A1 segment or more distal, and posterior cerebral artery P1 segment or more distal. Mann‐Whitney U test, Fisher exact test statistic, and T‐test statistic were used for analysis. Social science statistics software was used for data analysis. Results From August 2020 to December 2021, out of 175 patients who underwent EVT, 50 had MVO (n = 33 M2 occlusion, n = 12 M3 occlusion, n = 1 for P1, P2, A1, A2, A3 each). Twelve subjects with MVO received aggressive medical management with concurrent IV eptifibatide. Subjects between arms were similar at baseline (median NIHSS 11 [95% CI 10.75, 14.32]; mean age 71.5 [95% CI 69.24, 73.77]; male 48.39% [n = 30]). The difference between initial NIHSS and discharge NIHSS was statistically significant in the EVT arm (Z‐Score = 4.03; p‐value &lt; .00001) but not in the medical arm (Z‐score = 1.96; p‐value 0.05). Hemorrhagic transformation occurred in 28% (n = 14) of EVT arm and 16.67% (n = 2) of medical arm. This was not statistically significant (Fisher value: 0.71). Median 90 day mRS was 1 (95% CI [0.89, 2.11]). The difference between 90 day mRS was not significantly different (Z‐score = ‐1.20; p‐value 0.23). Conclusions In our patient cohort, endovascular therapy was safe in medium vessel occlusion and may have more favorable clinical outcomes as illustrated by higher delta NIHSS in the endovascular thrombectomy group. Larger, prospective studies are needed to validate our results.

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

PurposeTo 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 MethodsA 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. ResultsThe 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). ConclusionAccording 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.

Abstract TMP86: Clinical Outcomes Of Endovascular Thrombectomy Versus Acute Medical Treatment In Acute Ischemic Strokes Secondary To Medium Vessel Occlusion

Introduction: Acute ischemic stroke (AIS) from arterial occlusions are treated with emergent endovascular thrombectomy (EVT) when clinically appropriate. Clinical outcomes of EVT in medium vessel occlusion (MVO) compared to large vessel occlusion (LVO) have neither been well established nor compared to alternate medical management. Our aim was to evaluate outcomes of patients with AIS secondary to MVO undergoing EVT. Methods: We conducted a retrospective chart review of patients presenting to with MVO-associated AIS undergoing EVT or aggressive intra-arterial thrombolytic treatment with concurrent administration of IV eptifibatide. We assessed occlusion site, NIHSS (presentation, 7 day or discharge, 3 months), mRS (baseline, 90-day), and intracranial hemorrhage (ICH) rate. MVO was defined as occlusion of pure M2 middle cerebral artery without M1 segment involvement, anterior cerebral artery A1 segment or more distal, and posterior cerebral artery P1 segment or more distal. Mann-Whitney U test, Fisher exact test statistic, and T-test statistic were used for analysis. Results: From August 2020 to December 2021, out of 175 patients who underwent EVT, 50 had MVO (n=33 M2 occlusion, n=12 M3 occlusion, n=1 for P1, P2, A1, A2, A3 each). Twelve subjects with MVO received aggressive medical management with concurrent IV eptifibatide. Subjects between arms were similar at baseline (median NIHSS 11 [95% CI 10.75, 14.32]; mean age 71.5 [95% CI 69.24, 73.77]; male 48.39% [n=30]). The difference between initial NIHSS and discharge NIHSS was statistically significant in the EVT arm (Z-Score=4.03; p-value &lt; .00001) but not in the medical arm (Z-score=1.96; p-value 0.05). Hemorrhagic transformation occurred in 28% (n=14) of EVT arm and 16.67% (n=2) of medical arm. This was not statistically significant (Fisher value: 0.71). Median 90 day mRS was 1 (95% CI [0.89, 2.11]). The difference between 90 day mRS was not significantly different (Z-score=-1.20; p-value 0.23). Conclusion: In our patient cohort, endovascular therapy was safe in medium vessel occlusion and may have more favorable clinical outcomes as illustrated by higher delta NIHSS in the endovascular thrombectomy group. Larger, prospective studies are needed to validate our results.

Association of dissection features and primary collateral circulation with ischemic stroke in patients with spontaneous internal carotid artery dissection: evaluated using vessel wall-MRI and MRA.

To study the ischemic stroke risk factors in spontaneous internal carotid artery dissection (ICAD) patients via analyzing the dissection features and primary collateral circulation using vessel wall-MRI and magnetic resonance angiography. ICAD patients who had undergone VW-MRI were included in this study. A total of 36 patients were included and divided into ICAD stroke (N = 23) and non-stroke (N = 13) group. Dissection imaging features [intramural hematoma (IMH), length of IMH, intimal flap, double lumen, intraluminal thrombus, degree of stenosis] and primary collateral status were analyzed. The primary collateral score (0-4) was evaluated based on presence of anterior communicating and ipsilateral anterior cerebral artery A1 segment (0-2) and ipsilateral posterior communicating artery (0-2). There were no significant differences in dissection imaging features such as presence of double lumen, intimal flap, IMH, length of IMH and intraluminal thrombus between the two groups. Degree of stenosis and primary collateral score showed significant differences between the two groups. Both the poor primary collateral circulation and severe stenosis may play an important role in occurrence of ischemic stroke for spontaneous ICAD patients and good primary collateral circulation can help to reduce the incidence of infarction. ICAD is one of the major causes of ischemic stroke. Early evaluation of the status of the Circle of Willis in ICAD patients by MRI may help to make treatment strategies and improve clinical outcome.

Variations of Anterior Cerebral Artery (ACA) on CT Angiography (CTA)

Introduction: The variations in anterior cerebral artery (ACA) has high clinical significance for surgeons&#x0D; Aim: This study aims to assess the variations of ACA with the help of CT angiography (CTA)&#x0D; Methodology: This retrospective study was conducted from Nov 2019 to Feb 2020 at Lahore General Hospital, Lahore. In total, 150 patients went under detailed analysis. The demographic data such as age and gender were noted for each patient. The CTA was performed with the help of 128-slice CT scanner. The reports were assessed by an experienced radiologist. Anatomic variations were noted and presented as frequencies and percentages.&#x0D; Results: The study included 92 (61.33%) were females and 58 (38.66%) were males with mean age 50.2 ± 3.7 years. Azygos anterior cerebral artery was present in 14 patients (9%), hypoplasia of anterior cerebral artery A1 segment in 43 (35.66%) patients,11 (7.33%) patients showed bi-hemispheric anterior cerebral artery, right anterior cerebral artery dominance in 2 (1.33%) patients, 8 (4.33 %) were detected with congenital absence of A1 segment. Anterior cerebral artery trifurcation had prevalence of 6(3.2%).&#x0D; Conclusion: It can be concluded that anterior cerebral artery variations have low prevalence and CT angiography is a gold method for detecting them.

Association between symptomatic intracranial atherosclerotic disease and the integrity of the circle of Willis

The relationship between the severity of intracranial atherosclerotic disease and the circle of Willis integrity is unclear. In this brief report, we investigate the associations between symptomatic intracranial atherosclerotic disease and the integrity of the circle of Willis. Patients with symptomatic intracranial atherosclerosis were enrolled and underwent intracranial artery magnetic resonance vessel wall imaging and time-of-flight angiography. The presence or absence of an intracranial atherosclerotic plaque and its maximum wall thickness and stenosis were evaluated. The presence or absence of the A1 segment of the bilateral anterior cerebral arteries (from the internal carotid artery to the anterior communicating artery segment is called anterior cerebral artery A1 segment), and anterior communicating artery, the P1 segment of the bilateral posterior cerebral arteries (The P1 segment of the posterior cerebral artery is a horizontally outward segment), and bilateral posterior communicating arteries were determined. The associations of the intracranial plaque features with the integrity of the circle of Willis were analyzed. Of the 110 recruited subjects (57.2 ± 11.1 years; 65% males), 51 had intracranial plaques, and 44 had stenosis. In patients with bilateral A1 and P1 segments (n = 85), intracranial stenosis was more severe in patients with an anterior communicating artery than those without an anterior communicating artery (19.7% ± 21.7% vs. 1.4% ± 3.3%, p = 0.046). In patients with bilateral A1 and P1 segments and an anterior communicating artery (n = 79), intracranial stenosis was more severe in patients with posterior communicating arteries than those without posterior communicating arteries (27.9% ± 23.7% vs. 13.5% ± 17.9%, p = 0.007). The odds ratio of intracranial stenosis was 1.214 (95% confidence interval (CI), 1.054-1.398; p = 0.007) in discriminating for the presence of posterior communicating arteries in patients with bilateral A1 and P1 segments and an anterior communicating artery after adjusting for confounding factors. The severity of intracranial atherosclerosis was independently associated with the presence of posterior communicating arteries in patients with a complete anterior part of the circle of Willis.

Structural changes in the side branches and the circle of Willis following the use of flowdiverting stents.

This study aimed to evaluate the diameter and flow changes in the circle of Willis and side branches following the use of FDSs extending from the middle cerebral artery (MCA) to the internal carotid artery (ICA) for the treatment of aneurysms in the terminal segment of ICA, and the clinical results. This study was conducted in a single center between January 2012 and April 2018 in patients with the anterior choroidal artery (AChoA), the posterior communicating artery (PComA), and the ICA terminal segment aneurysms treated with the FDSs. The changes in aneurysm size, arterial structures covered by the FDSs, and changes in the diameter and flow in arteries forming the circle of Willis were retrospectively analyzed. Fourteen patients with a total of 25 aneurysms treated with FDSs extending from MCA to ICA were evaluated. The mean aneurysm fundus size was 5.14 mm (range 1.5-22 mm). Before treatment, the anterior communicating artery (AComA) was patent in all patients. Implanted FDSs covered the anterior cerebral artery (ACA) and AChoA in all patients (100%), nonhypoplasic PComA in two patients (14.28%), and the ophthalmic artery in nine (64.3%). The mean follow-up time was 36.78 ± 22.44 months. In follow-up, there was a decrease in the mean ipsilateral ACA A1 segment diameter from 1.99 ± 0.58 cm to 1.81 ± 0.31 cm (p = 0.01). The mean contralateral A1 segment diameter increased from 1.66 ± 0.48 cm to 1.93 ± 0.42 cm (p = 0.004). All aneurysms were totally occluded. If the AComA is patent, ipsilateral anterior circulation can be compensated through modifications in the contralateral ACA A1 segment in patients with ICA terminal segment aneurysms treated with FDSs extended from MCA to ICA and covering ACA. Although covering the anterior choroidal and lenticulostriate arteries by FDSs, ischemic complications may not occur frequently. Thus, this effective therapy can be applied more safely.

Greater hemodynamic stresses initiated the anterior communicating artery aneurysm on the vascular bifurcation apex

ObjectiveTo investigate hemodynamic stresses associated with the anterior communicating artery (Acom) aneurysm formation using computational fluid dynamics (CFD) analysis. MethodsThree-dimensional geometries of the anterior cerebral artery (ACA) bifurcations in 20 patients with Acom aneurysms and 20 control subjects were used for CFD analysis to investigate hemodynamic stresses including the total and dynamic pressure, wall shear stress (WSS), vorticity and strain rate. ResultsAt the direct flow impinging center on the bifurcation apex, the total pressure was the maximal but decreased quickly from the impinging center to both daughter branches. The WSS, dynamic pressure, vorticity and strain rate were the minimal at the direct impinging center but increased rapidly and reached the peaks at both daughter branches. The ACA bifurcation angle was significantly (P < 0.001) greater in patients with than without Acom aneurysms (144.2° ± 4.1° vs. 105.1° ± 3.2°). Most aneurysms (70% and 85%, respectively) were deviated to the smaller daughter branch or to the daughter branch forming a smaller angle with the A1 segment of ACA, where the hemodynamic stresses were significantly (P < 0.05) greater than those on the contralateral daughter branch. After aneurysm formation, the hemodynamic stresses on the aneurysm dome were all significantly decreased compared with at the aneurysm initiation site with aneurysm virtual removal (P < 0.001). ConclusionFormation of the Acom aneurysm is closely associated with and is to decrease the locally abnormally enhanced hemodynamic stresses.

Cerebral collaterals and stroke in patients with isolated carotid artery dissections

To investigate potential association between collateral arterial supply and stroke in patients with isolated internal carotid artery dissection (iCeAD). We hypothesized a lower risk of stroke in patients with more robust collateral supply. This is a single-center, retrospective review of iCeAD patients between 1994 and 2018. iCeAD patients with sufficient neuroimaging data were included. Patients were categorized based on cerebral infarction (stroke) on neuroimaging. The collaterals score, ranging from 0 to 8 with higher scores indicating more robust collaterals, was assessed based on contributions from leptomeningeal arteries (0–2 points), anterior communicating artery (0–2 points) and anterior cerebral artery A1 segment (0–2 points), and posterior communicating artery (0–2 points). The study included 62 iCeAD patients, comprising 33 and 29 patients in the stroke and no stroke groups, respectively. Neurological motor deficit (p < 0.001) and internal carotid artery occlusion (p = 0.033) were independent predictors of stroke. More robust collaterals was associated with lower stroke risk (p = 0.032) in univariable analysis, but not after adjustment for baseline differences. The collaterals score performed poorly in receiver-operating characteristics (ROC) curve analysis, with area under the ROC (AUROC) curve of 0.640. A collaterals score of >4 had a sensitivity and specificity of 89.7% and 36.4% for no stroke, respectively. The covariate-adjusted AUROC curve was 0.514. Collateral circulation appeared to be a poor predictor of cerebral infarction in patients with isolated iCeAD. Future studies in larger, independent cohorts are needed to better understand the interaction of collaterals with stroke in cervical artery dissection.

Intracranial arterial variations and their relation with cerebral aneurysms: Analysis of 640 patients

Aim: To evaluate prevalence of cerebral arterial variations in Turkish population and association of the variations with cerebral aneurysmsMaterials and Methods: Digital subtraction angiography of 640 consecutive patients between January 2011-December 2013 were evaluated retrospectively. Patients with aneurysms were compared with patients without aneurysm to determine the effect of variations. Comparisons were made using Chi square or Fisher exact test for categorical variables and Student's t test or Mann Whitney U test for continuous variables.Results: The most common variation in the anterior circulation was hypoplasia of anterior cerebral artery A1 segment and the most common variation in the posterior circulation was fetal origin of the posterior cerebral artery. Hypoplasia and aplasia of the anterior cerebral artery A1 segment was significantly more frequent in patients with anterior communicating artery aneurysms than the control group (p:0.001). Prevalence of azygos anterior cerebral artery variation was higher in distal anterior cerebral artery aneurysms than the control group (p 0.001). There was no association between bihemispheric anterior cerebral artery and anterior communicating artery aneurysms (p = 0.453). Similarly, no significant association of fetal origin of posterior cerebral artery with posterior communicating artery aneurysms was found (p = 0.133). Conclusion: Prevalence of cerebral arterial variations in this study were compatible with literature. Some variations may play a role in development of aneurysms by alterations in hemodynamics and increasing shear wall stress. Further larger studies are needed to clarify the relation between variations in cerebrovascular structure and aneurysm formation.

Treatment of a Fusiform Anterior Cerebral Artery Aneurysm by Remodeling the Circle of Willis with Flow Diversion: A Novel Technical Note

Fusiform aneurysms are challenging lesions to manage given their poorly understood natural history and lack of a distinct neck. Historically, they have been treated surgically but endovascular management has recently evolved as a viable alternative. In this case, we describe a novel flow diversion technique for treatment of a fusiform anterior cerebral artery (ACA) aneurysm by jailing the compromised parent vessel obtaining endovascular aneurysm trapping. A 25-year-old man underwent brain magnetic resonance imaging and magnetic resonance angiography for workup of a headache, which revealed a fusiform right ACA A1 segment aneurysm. The patient subsequently underwent catheter digital subtraction angiography, which confirmed a 9× 5.5 mm fusiform right ACA A1 segment aneurysm. The patient elected to undergo endovascular treatment. A Pipeline Embolization Device (Medtronic, Dublin, Ireland) was placed from the right anterior cerebral artery to the right middle cerebral artery, thereby jailing the right ACA A1 segment. At 6-month follow-up, the patient was asymptomatic and his headache had resolved. An angiogram was obtained, showing patency of the Pipeline Embolization Device and near complete occlusion of the right ACA A1 segment. The right ACA A2 segment remained patent via collateral flow through the anterior communicating artery. These findings were confirmed on magnetic resonance imaging. The patient remained asymptomatic for the duration of the follow-up. This case illustrates the efficacy of the Pipeline Embolization Device for treatment of a fusiform anterior circulation aneurysm via remodeling the circle of Willis.

Abstract TMP101: Relationship Between RNF213 p.R4810K (c.14429G&gt;A) Variant and Anatomical Variations of the Circle of Willis

Background and purpose: RING finger protein 213 ( RNF213 ) gene is strongly associated with intracranial arterial stenosis as well as Moyamoya disease and its dysregulation is known to impair cerebral perfusion in rodents. We thus investigated the relationship between RNF213 p.R4810K (c.14429G&gt;A) variant and the anatomical variations of the circle of Willis in cerebrovascular disease. Methods: We consecutively enrolled non-cardioembolic stroke or transient ischemic attack patients with (n = 20) or without (n = 80) RNF213 p.R4810K (c.14429G&gt;A) variation from those who participated in the biobank of our Institute over the past 2 years. Moyamoya disease cases were excluded. We evaluated anatomical variations of the vessels constituting the circle of the Willis, namely, intracranial internal carotid artery, anterior communicating artery (AcomA), anterior cerebral artery A1 segment, posterior communicating artery (PcomA), posterior cerebral artery P1 segment, and middle cerebral artery M1 segment, using maximum intensity projection of a time-of-flight magnetic resonance angiography collected at 3 Tesla. Results: The RNF213 p.R4810K (c.14429G&gt;A) variant carrier had higher frequency of focal narrowing of the M1 segment compared to the non-carrier (50% vs 10%, p&lt;0.01) and an absence of AcomA (15% vs 3.7%, p=0.09). By contrast, unexpectedly, unilateral or bilateral absence of PcomA was significantly less frequent (25% vs 61%, p&lt;0.01). Multivariate analysis adjusted for age and sex showed that the variant carrier state was independently associated with unilateral or bilateral presence of PcomA (odds ratio (OR) 4.44, 95% confidence interval (CI) 1.01 - 20.6, p&lt;0.05) and focal M1 narrowing (OR 3.30, 95% CI 0.82 - 12.6, p=0.09). Conclusions: The RNF 213 p.R4810K (c.14429G&gt;A) variant carrier showed higher frequency of arteriopathy in the anterior circulation accompanied by higher patency rate of PcomA. In the variant carrier, dysplasia of the anterior circulation arteries may lead to compensatory collateral flow from posterior to anterior circulation through PcomA.

Magnetic resonance angiography of hypoplastic A1 segment of anterior cerebral artery at 3.0-Tesla in Andhra Pradesh population of India.

Pre-communicating or A1 segment of anterior cerebral artery (A1ACA) hypoplasia can negotiate the anterior cerebral circulation. Not many studies have been examined the association of hypoplastic A1ACA and cerebral ischemic stroke (CIS). In this study the authors' want to accomplish the relationship between hypoplastic A1ACA and outcomes among the patients with CIS in Andhra Pradesh population of India. Retrospective review of prospectively identified 201 adult patients with CIS from 2015 to 2017 was achieved. Patients underwent 3.0T intracranial magnetic resonance angiography were compared with clinical and radiological aspects between male and female cases of A1ACA hypoplasia with associated variations in the circle of Willis. The obtained data was statistically analysed using SPSS software version 16.0 for Windows and P-value <0.05 was considered as significant. Chi-square test was applied to find out the association between the sex and incidence of hypoplastic A1ACA. Sixty-four of 201 patients with A1ACA hypoplasia with no aplastic cases were recorded. It was found to be more in males than females and common on right than left side. Frequent neurological indications such as headache, dizziness, visual instability, nausea, weakness of extremities and seizure were noted and most cases were associated with CIS. Hypoplastic A1ACA often associated with ischemia of terminal branches of ipsilateral ACA which is compromised by the blood flow via contralateral ACA. In this study, though the CIS is not directly related to hypoplastic A1ACA, any alterations in A1 segment is a considerable risk factor of stroke.

Sole angioplasty with tiny balloon for high-risk complex symptomatic intracranial atherosclerotic stenosis

Objective: To explore the safety and short-term efficacy of sole angioplasty with tiny balloon for symptomatic intracranial atherosclerotic stenosis (ICAS) patients with complex lesions refractory. Methods: Consecutive 11 patients with complex ICAS lesions treated by sole angioplasty with tiny balloon (diameter≤2 mm) from September 2016 to November 2017 at Department of Neurosurgery, Beijing Hospital were retrospectively reviewed. Patients' demographics, lesions characteristics, procedures, complications, and clinical and imaging follow-up data were collected. There were 6 male and 5 female patients with mean age of 63.6 years (range: 45 to 77 years). Clinical manifestations were transient ischemia attack (TIA) in 4 cases, progressive ischemic stroke in 3 cases, recurrent stroke in 3 cases, and 1 case for preparation of scheduled radical resection of colon cancer. ICAS locations were middle cerebral artery M1 segment in 5 cases, M2 segment in 1 case, anterior cerebral artery A1 segment in 2 cases, and intracranial vertebral artery in 3 cases. Mean degree of ICAS stenosis was 92%. Lesion morphology was type A in 3 cases, B in 4 cases and C in 4 cases by Mori classification. Forward flow by modified thrombolysis in cerebral infarction (mTICI) was grade 1 to 2a in 8 cases, 2b in 3 cases. Collateral compensation grading was grade 2 in 5 cases, grade 3 in 6 cases. Results: Technique success rate was 10/11, peri-procedural complication rate was 1/11. Post-procedural forward flow in all cases had been enhanced and 10 cases obtained mTICI 2b to 3. Ten patients got favorable outcomes (modified Rankin score 0 to 2) at discharge. With a mean clinical follow-up time of 5.4 months, 1 patient was found to have TIA recurrence. With a mean clinical follow-up time of 7.4 months, 1 patient was found to have TIA recurrence. Eight in 11 cases obtained imaging follow-up during 3 months, and none restenosis was found. Conclusion: For symptomatic ICAS complex lesions, sole angioplasty with tiny balloon demonstrates relatively high safety with satisfactory short-term clinical and imaging results.

Morphometric analysis of the arteries of Willis Polygon

Abstract Objective: Willis polygon forms the basis of the arterial circulation of the cerebrum. Willis polygon is a vascular structure whom variations are not rare. Knowledge of the anatomy and preservation of its integrity is crucial for performing neurovascular surgery and intracranial tumour surgery. Because of the important vascular and neurological structures, approaches to this region are considered extremely risky. One of the main variations in-person basis is the diameter differences of the arteries, which forms Willis polygon, between the left and right hemispheres. About structure and variations, studies of Rhoton and Yasargil had formed the touchstone. Our aim is to contribute to the literature and clinical studies, to be done in the future, by comparing our results with previous studies about variations and morphometric features of Willis polygon. Methods: Arteries of 30 fresh cadaver brains were examined during autopsies in T.C. Ministry of Justice Istanbul Forensic Science Institute. Bilaterally anterior cerebral artery A1 segment lengths, distance between anterior communicating artery-callosomarginal artery outputs, posterior cerebral artery P1 segment lengths were measured using a digital calliper. After dissections and measures, photos of the region were taken and vascular anatomy and variations noted. From every single cerebrum samples were obtained from bilaterally A1, A2, callosomarginal artery, middle cerebral artery, posterior communicant artery, P1 and basilar artery. Samples were fixed by using 10% buffered-formalin. Taken samples were transported to Marmara University Faculty of Medicine, Department of Anatomy Laboratory. Samples were examined and interior diameters were measured under the microscope. Results: Our results with artery diameters and lengths were similar with literature. Different from literature, in anterior cerebral artery A1 segment, posterior cerebral artery P1 segment and posterior communicant artery no aplasia were noted. In 50% of the samples, callosomarginal artery were originate from A2 segment. In one case, we observed left and right pericallosal arteries were joined together at the end of the A2 segment and continued as a single pericallosal artery. We could not find any information about this variation in the literature. Conclusion: Before surgical operations, detailed knowledge of Willis polygon and evaluation of the pre-op cerebral angiography considering possible variations, reduce mortality and morbidity ratios. In addition, because of the role of flow gradients of Willis polygon in aneurysm formation, and in terms of better understanding the collateral circulation which is important in vascular occlusive diseases and vascular surgery, we believe, more anatomic studies about this region needed.

Ruptured Dissecting Aneurysm of the Anterior Cerebral Artery A1 Segment Associated with Multiple Intracranial Aneurysms

Ruptured Dissecting Aneurysm of the Anterior Cerebral Artery A1 Segment Associated with Multiple Intracranial Aneurysms