Intracranial Artery Research Articles

Periodontitis is associated with subclinical cerebral and carotid atherosclerosis in hypertensive patients: A cross-sectional study

ObjectiveTo examine the relationship between periodontitis and subclinical intracranial atherosclerosis. The association of periodontitis with preclinical markers of atherosclerosis in other vascular territories was also explored.Material and methodsThis was a cross-sectional study where 97 elderly subjects with a previous history of hypertension received an ultrasonographic evaluation to assess subclinical atherosclerosis in different vascular territories: (1) cerebral [pulsatility (PI) and resistance index (RI) of the middle cerebral artery], (2) carotid [intima-media thickness (IMT)], and (3) peripheral [ankle-brachial index (ABI)]. Additionally, participants underwent a full-mouth periodontal assessment together with blood sample collection to determine levels of inflammatory biomarkers (leukocytes, fibrinogen, and erythrocyte sedimentation rate), lipid fractions (total cholesterol and high- and low-density lipoprotein), and glucose.ResultsSixty-one individuals had periodontitis. Compared to subjects without periodontitis, those with periodontitis showed higher values of PI (1.24 ± 0.29 vs 1.01 ± 0.16), RI (0.70 ± 0.14 vs 0.60 ± 0.06), and IMT (0.94 ± 0.15 vs 0.79 ± 0.15) (all p < 0.001). No statistically significant differences were found neither for ABI or for other clinical and biochemical parameters. An independent association was found between periodontitis and increased intracranial atherosclerosis (ORadjusted = 10.16; 95% CI: 3.14–32.90, p < 0.001) and to a lesser extent with thicker carotid IMT (ORadjusted = 4.10; 95% CI: 1.61–10.48, p = 0.003).ConclusionsPeriodontitis is associated with subclinical atherosclerosis in both intracranial and carotid arteries in elderly subjects with hypertension.Clinical relevanceThe association of periodontitis with intracranial atherosclerosis implies that periodontitis patients might have greater chances to develop ischemic stroke in the future.

564 The Influence of Presenting Glucose and Glycated Hemoglobin on Outcomes Following Mechanical Thrombectomy for Anterior Circulation Large Vessel Occlusion

INTRODUCTION: Elevated presenting glucose and glycated hemoglobin (HbA1C) values may be associated with worse outcomes following mechanical thrombectomy (MT) for anterior circulation large vessel occlusion (ACLVO). METHODS: All patients who underwent MT for ACLVO between 2015 – 2021 at a single institution were reviewed. The outcomes included favorable functional status (modified Rankin Scale [mRS] 0 – 2) at 90 days, any intracranial hemorrhage (ICH), parenchymal hemorrhage, and malignant middle cerebral artery infarction (MMI). Multivariate logistic regression analyses adjusting for age, premorbid mRS, admission NIHSS, ASPECTS, collateral score, tPA administration, onset to reperfusion time, and TICI grade were performed. Youden’s index was used to identify thresholds for glucose and HbA1C that optimized area under the receiving operator characteristic curve for predicting outcomes. RESULTS: A total of 332 patients were included. The mean (SD) age was 70.9 years (15.1), 50.3% of patients were female, and 26.9% of patients had a history of diabetes. The median (IQR) presenting glucose, SGR, and HbA1C values were 118 mg/dL (40), 1.0 (0.35), and 5.7% (1.0), respectively. Presenting glucose was associated with any ICH (OR 1.38, 95% 1.08 – 1.80) and MMI (OR 1.48, 95% CI 1.06 – 2.03), but not functional status. SGR was not associated with any outcome. Presenting HbA1C was associated with MMI (OR 1.43, 95% 1.02 – 2.02) but not functional status or ICH. The optimal threshold among glucose values for predicting ICH and MMI were 167 mg/dL and 128 mg/dL, respectively. For HbA1c, the threshold for predicting MMI was 6.0. CONCLUSIONS: Presenting glucose and HbA1C were associated with MMI, and glucose was associated with ICH after MT for ACLVO. Improved glucose control prior to admission could decrease the odds of these events.

Comparison of single-postlabeling delay and seven-delay three-dimensional pseudo-continuous arterial spin labeling in the assessment of intracranial atherosclerotic disease.

The assessment of cerebral blood flow (CBF) is crucial in the evaluation of intracranial atherosclerotic disease. This study was performed to compare single postlabeling delay (PLD) 3-dimensional pseudo-continuous arterial spin labeling (3D-pCASL) and 7-delay 3D-pCASL magnetic resonance imaging in patients with intracranial atherosclerotic stenosis. A total of 26 patients with moderate to severe atherosclerotic stenosis or occlusion of an intracranial artery were prospectively enrolled in the study. Perfusion parameters were obtained in various regions of interest (ROIs), namely CBF for single PLDs of 1,525 ms (CBF1525 ms), 2,025 ms (CBF2025 ms), and 2,525 ms (CBF2525 ms) with 3D-pCASL, as well as arterial transit time (ATT) and transit-corrected CBF (CBFtransit-corrected) for 7-delay 3D-pCASL. The consistency of the perfusion parameters between single-PLD 3D-pCASL and 7-delay 3D-pCASL was investigated, and the relationship between vascular stenosis and perfusion parameters was explored. Bland-Altman plots compared the CBF values derived from single-PLD 3D-pCASL to those from CBFtransit-corrected. ATT significantly correlated with the difference between CBFtransit-corrected and CBF1525 ms, CBF2025 ms, and CBF2525 ms, respectively (P<0.05). Binary logistic regression analysis revealed that the CBFtransit-corrected and ATT correlated with the presence of moderate or more severe stenotic vascular territories (P<0.05). The single-PLD 3D-pCASL and the 7-delay 3D-pCASL showed inconsistencies in the assessment of CBF, and the perfusion parameters generated under the standard single-PLD 3D-pCASL were more affected by ATT. Moreover, CBFtransit-corrected and ATT were consistent with stenotic vascular territories, which is useful in the evaluation of intracranial atherosclerotic disease.

Cerebral autoregulation and blood flow distribution in the precerebral arteries for determining indications of extra-intracranial bypass in patients with carotid artery occlusion

Background. Prevention of ischemic stroke in patients with carotid artery occlusion is conventionally associated with performing cerebral revascularization. However, determining the indications for it is still an actual problem. The informative value of noninvasive assessment of cerebral autoregulation and blood flow distribution in the precerebral arteries in patients with carotid artery stenosis is shown. At the same time, in patients with carotid artery occlusion, these indicators have been studied to a lesser extent.Aim. To evaluate the informative value of cerebral autoregulation and blood flow distribution in the precerebral arte ries for determination the indications of extra‑intracranial bypass in patients with carotid occlusion.Materials and methods. 54 patients (aged from 41 to 83 y. o.) with carotid artery occlusion were studied. Blood flow velocity in intracranial arteries was determined with transcranial Doppler (system Multi‑Dop X), whereas flow velocity index in precerebral arteries – with duplex scanning (system Vivid Е). Cerebral autoregulation was assessed based on phase shift between spontaneous oscillations of blood flow velocity in basal cerebral arteries and systemic blood pressure within the range of Mayer’s waves (80–120 mHz).Results. The state of cerebral autoregulation was imparied on both sides in 90 % patients with the symptomatic carotid occlusion (0.3 ± 0.3 rad ipsilateral, 0.7 ± 0.6 rad contralateral). The state of cerebral autoregulation was not impaired in 79 % patients with asymptomatic carotid occlusion (1.0 ± 0.3 rad ipsilateral, 1.1 ± 0.4 rad contralateral). The flow velocity index in the contralateral internal carotid artery (306 ± 109 ml / min) and the ipsilateral vertebral (139 ± 69 ml / min) and external carotid (175 ± 72 ml / min) arteries was increased.Conclusions. Noninvasive preoperative assessment of cerebral autoregulation and blood flow distribution in the precerebral arteries makes to evaluate the state of the cerebrovascular reserve to quantify and can be used to determining indications for cerebral revascularization in patients with carotid occlusion.

Machine learning and reduced order modelling for the simulation of braided stent deployment.

Endoluminal reconstruction using flow diverters represents a novel paradigm for the minimally invasive treatment of intracranial aneurysms. The configuration assumed by these very dense braided stents once deployed within the parent vessel is not easily predictable and medical volumetric images alone may be insufficient to plan the treatment satisfactorily. Therefore, here we propose a fast and accurate machine learning and reduced order modelling framework, based on finite element simulations, to assist practitioners in the planning and interventional stages. It consists of a first classification step to determine a priori whether a simulation will be successful (good conformity between stent and vessel) or not from a clinical perspective, followed by a regression step that provides an approximated solution of the deployed stent configuration. The latter is achieved using a non-intrusive reduced order modelling scheme that combines the proper orthogonal decomposition algorithm and Gaussian process regression. The workflow was validated on an idealized intracranial artery with a saccular aneurysm and the effect of six geometrical and surgical parameters on the outcome of stent deployment was studied. We trained six machine learning models on a dataset of varying size and obtained classifiers with up to 95% accuracy in predicting the deployment outcome. The support vector machine model outperformed the others when considering a small dataset of 50 training cases, with an accuracy of 93% and a specificity of 97%. On the other hand, real-time predictions of the stent deployed configuration were achieved with an average validation error between predicted and high-fidelity results never greater than the spatial resolution of 3D rotational angiography, the imaging technique with the best spatial resolution (0.15mm). Such accurate predictions can be reached even with a small database of 47 simulations: by increasing the training simulations to 147, the average prediction error is reduced to 0.07mm. These results are promising as they demonstrate the ability of these techniques to achieve simulations within a few milliseconds while retaining the mechanical realism and predictability of the stent deployed configuration.

The effect of intensive statin therapy in non-symptomatic intracranial arteries: The STAMINA-MRI sub-study.

Pleiotropic effects of statins result in the stabilization of symptomatic intracranial arterial plaque. However, little is known about the effect of statins in non-symptomatic cerebral arteries. We hypothesized that intensive statin therapy could produce a change in the non-symptomatic cerebral arteries. This is a sub-study of a prospective observational study under the title of "Intensive Statin Treatment in Acute Ischemic Stroke Patients with Intracranial Atherosclerosis: a High-Resolution Magnetic Resonance Imaging (HR-MRI) study." Patients with statin-naive acute ischemic stroke who had symptomatic intracranial artery stenosis (above 50%) were recruited for this study. HR-MRI was performed to assess the patients' cerebral arterial status before and 6 months after the statin therapy. To demonstrate the effect of statins in the non-symptomatic segment of intracranial cerebral arteries, we excluded symptomatic segments from the data to be analyzed. We compared the morphological changes using cerebrovascular morphometry. A total of 54 patients (mean age: 62.9 ± 14.4 years, 59.3% women) were included in this study. Intensive statin therapy produced significant morphological changes of overall cerebral arteries. Among the morphological features, the arterial luminal area showed the highest number of significant changes with a range from 5.7 and 6.7%. Systolic blood pressure (SBP) was an independent factor associated with relative changes in posterior circulation bed maximal diameter percentage change (beta -0.21, 95% confidence interval -0.36 to -0.07, p = 0.005). Intensive statin therapy produced a favorable morphological change in cerebral arteries of not only the target arterial segment but also non-symptomatic arterial segments. The change in cerebral arterial luminal diameter was influenced by the baseline SBP and was dependent on the topographic distribution of the cerebral arteries.Clinical Trial Registration: ClinicalTrials.gov, identifier NCT02458755.

Delta-Like Factor 1 Negatively Regulates Angiogenesis as a Target Gene of MIR-126-5P after Indirect Revascularization Surgery in Patients with Moyamoya Disease

Introduction: Moyamoya disease (MMD) is a chronic cerebral hypoperfusion state with increased narrowing of the intracranial internal carotid artery. Objectives: The main objective of the study is to analyses the delta-like factor 1 negatively regulates angiogenesis as a target gene of miR-126-5p after indirect revascularization surgery in patients with moyamoya disease. Material and methods: This retrospective study was conducted in Akhtar Saeed Medical College Lahore during 2020 to 2021. First, we compared the DLK1 expression in DM tissues from patient with moyamoya disease (n = 8) and unruptured aneurysms (n = 8, control group). DM samples (1.0 × 0.5 cm) were collected from patients with moyamoya disease during revascularization procedures. DM samples were harvested from the temporal part of the head and stored for further use. Results: EPC markers CD31, VE-cadherin, and VEGFR-2 were strongly expressed in cultured cells, while hematopoietic marker CD133 did not display remarkable expression, suggesting highly purified EPC isolation. Practical implication: This study will be helpful in EC proliferation and angiogenesis. Conclusion: It is concluded that DLK1, a target gene of miR-126-5p, negatively regulates EC proliferation and angiogenesis and that downregulating DLK1 expression potentially promotes angiogenesis in chronically ischaemic brains. Keywords: DLK1, EC, Proliferation, Angiogenesis

Moyamoya Vasculopathy in Neurofibromatosis Type 1 Pediatric Patients: The Role of Rare Variants of RNF213

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in NF1 gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events. RNF213 gene mutations have been associated with MMD, so we investigated whether rare variants of RNF213 could act as genetic modifiers of MMS phenotype in a pediatric cohort of 20 MMS children, 25 children affected by isolated MMD and 47 affected only by isolated NF1. By next-generation re-sequencing (NGS) of patients' DNA and gene burden tests, we found that RNF213 seems to play a role only for MMD occurrence, while it does not appear to be involved in the increased risk of Moyamoya for MMS patients. We postulated that the loss of neurofibromin 1 can be enough for the excessive proliferation of vascular smooth muscle cells, causing Moyamoya arteriopathy associated with NF1. Further studies will be crucial to support these findings and to elucidate the possible role of other genes, enhancing our knowledge about pathogenesis and treatment of MMS.

Effects of endovascular recanalization on symptomatic non-acute occlusion of intracranial arteries

To investigate the effect and safety of recanalization surgery for non-acute occlusion of large intracranial arteries and factors affecting clincial outcomes. Patients with non-acute occlusion of internal carotid artery (ICA), middle cerebral artery (MCA), and vertebrobasilar artery (VBA) treated with recanalization were retrospectively enrolled. The clinical and angiographic data were analyzed. 177 patients were enrolled, including 67 patients with intracranial ICA occlusion, 52 with MCA occlusion, and 58 with VBA occlusion. Successful recanalization was achieved in 152 (85.9%) patients. Complications occurred in 15 patients (8.5%). Followed up for 3–7 months, the 90 day mRS was significantly improved compared with that before the procedure. Among 152 patients with successful recanalization, eight patients experienced reocclusion (5.3%), and 11 patients experienced restenosis (7.2%). Successful recanalization was significantly (P < 0.05) associated with occlusion duration, calcification or angulation of the occluded segment. Complications were significantly (P < 0.05) associated with location of occlusion, hyperlipidemia, and patients’ height. Restentosis or reocclusion at follow-up was significantly (P < 0.05) associated with complications and mRS at 90 days. The significant (P < 0.05) independent risk factors were angulation and calcification for successful recanalization, hyperlipidemia for complications, and mRS at 90 days for restenosis or reocclusion at follow-up. Recanalization surgery may be a safe and effective approach for patients with non-acute symptomatic occlusion of large intracranial arteries, and factors significantly independently associated with successful recanalization, periprocedural complications and restenosis or reocclusion after surgery have been identified for future reference to improve clinical outcomes.

Transcranial Doppler Echography Measurement in Hemodialysis Patients: The Potential Role of Angiotensin II Receptor Blockades on Cerebrovascular Circulation.

Although hemodialysis (HD) patients have an elevated risk of strokes, there are few reports about transcranial doppler (TCD) echography measurements. It is well-known that angiotensin II receptor blockades (ARBs) protect against cardiovascular complications. In this study, we measured intracranial artery (ICA) velocity using TCD echography and studied the associated factors with its velocity in HD patients by a comparison with or without ARBs. We conducted a cross-sectional study in a single hospital. We included 61 patients who had measurable ICA velocity by TCD echography. Among them, the ARB usage group consisted of 22 subjects, whilst the non-ARB usage group consisted of 39 subjects. Patients in the ARB (+) and ARB (-) groups did not show any difference in basic characteristics. ICA blood flow velocity in all intracranial arteries tended to show greater values in the ARB group than those in the non-ARB group. Particularly, blood velocity in the middle cerebral artery (MCA) (maximal flow velocity) statistically increased in the ARB group, respectively. In a univariate analysis, MCA maximum velocity was significantly associated with ARB usage (p = 0.011) and low hematocrit levels (p = 0.045). The multivariate analysis chose only ARB usage as an independent factor associated with left MCA maximum velocity (p = 0.022). We showed that dialysis patients with ARBs have significantly higher ICA blood velocity. ARBs might have a potential benefit for maintaining ICA blood flow in HD patients.

Early ischemic recurrence in acute spontaneous cervical artery dissection

Background and PurposeEarly ischemic recurrence (EIR) following the diagnosis of acute spontaneous cervical artery dissection (CeAD) has been little investigated. We aimed to determine the prevalence and determinants on admission of EIR in a large single-center retrospective cohort study of patients with CeAD. MethodsEIR was defined as any ipsilateral clinical or radiological cerebral ischemia or intracranial artery occlusion, not present on admission and occurring within 2 weeks. CeAD location, degree of stenosis, circle of Willis support, presence of intraluminal thrombus, intracranial extension, and intracranial embolism were analyzed on initial imaging by 2 independent observers. Uni- and multivariate logistic regression was used to determine their association with EIR. ResultsTwo hundred thirty-three consecutive patients with 286 CeAD were included. EIR was observed in 21 patients (9%,95%CI=5–13%) with a median time from diagnosis of 1.5 days (range:0.1–14.0 days). No EIR was observed in CeAD without ischemic presentation or with less than 70% stenosis. In the remaining cases, poor circle of Willis (OR=8.5, CI95%=2.0–35.4, p = 0.003), CeAD extending to other intracranial arteries than just V4 (OR=6.8, CI95%=1.4–32.6, p = 0.017), cervical artery occlusion (OR=9.5, CI95%=1.2- 39.0, p = 0.031), and cervical intraluminal thrombus (OR=17.5, CI95%=3.0–101.7, p = 0.001) were independently associated with EIR. ConclusionsOur results suggests that EIR is more frequent than previously reported, and that its risk might be stratified on admission with a standard workup. In particular, the presence of a poor circle of Willis, intracranial extension (other than just V4), cervical occlusion, or cervical intraluminal thrombus are associated with high risk of EIR, for which specific management should be further evaluated.

Study of Typical Ruptured and Unruptured Intracranial Aneurysms Based on Fluid–Structure Interaction

Most intracranial aneurysms (IAs) will be abnormal bulges on the walls of intracranial arteries that result from the dynamic interaction of geometric morphology, hemodynamics, and pathophysiology. Hemodynamics plays a key role in the origin, development, and rupture of IAs. In the past, hemodynamic studies of IAs were mostly based on the rigid wall hypothesis of computational fluid dynamics, and the influence of arterial wall deformation was ignored. We used fluid-structure interaction (FSI) to study the features of ruptured aneurysms, because it can solve this problem very well and the simulation will be more realistic. A total of 12 IAs, 8 ruptured and 4 unruptured, at the middle cerebral artery bifurcation were studied using FSI to better identify the characteristics of ruptured IAs. We studied the differences in the hemodynamic parameters, including the flow pattern, wall shear stress (WSS), oscillatory shear index (OSI), and displacement and deformation of the arterial wall. Ruptured IAs had a larger low WSS area and more complex, concentrated, and unstable flow. Also, the OSI was higher. In addition, the displacement deformation area at the ruptured IA was more concentrated and larger. A large aspect ratio; a large height/width ratio; complex, unstable, and concentrated flow patterns with small impact areas; a large low WSS region; large WSS fluctuation, high OSI; and large displacement of the aneurysm dome could be risk factors associated with aneurysm rupture. If similar cases are encountered when simulation is used in the clinic, priority should be given to diagnosis and treatment.

Role of CT Angiography in Detection of Extracranial Carotid and Vertebral Artery Disease in Patients With Acutely Ruptured Intracranial Aneurysms

Introduction: Computed tomography (CT) and CT angiography are standard imaging modalities for suspected acute intracerebral hemorrhage due to ruptured intracranial aneurysms. In this clinical setting, several protocols of computed tomography and CT angiography may be implemented. The standard CT angiography protocol is limited to intracranial vessels. The extended protocol may also include carotid and vertebral arteries and the aortic arch.Objective: To define the CT angiography role in detection of extracranial carotid and vertebral artery disease and clinical significance of this method for patients with suspected acute intracerebral hemorrhages due to ruptured intracranial aneurysms.Materials and methods: The study included 275 neurosurgical patients with acute nontraumatic intracranial hemorrhages due to ruptured intracranial aneurysms who were treated in Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) from September 2017 to August 2020. Computed tomography and CT angiography were performed in all patients. The scanned area included both intracranial and extracranial arteries (an arch-to-vertex angiogram) to detect extracranial carotid and vertebral artery diseases such as stenoses, occlusions, tortuosity, and hypoplasia.Results: Atherosclerosis of internal carotid and vertebral arteries was diagnosed in 95 patients (34.5% of the total number of patients included in the study). In 13 (4.7%) patients these stenoses were hemodynamically significant. We identified a high frequency of tortuous carotid and vertebral arteries (122 cases, 44.3%) and vertebral artery hypoplasia (59 cases, 21.5%). The carotid and vertebral artery stenoses and congenital anomalies of vertebral arteries (however, not of carotid arteries) were associated with a higher incidence of unfavorable outcomes after endovascular treatment of intracranial aneurysms.Conclusions: The optimal CT angiography protocol for acute nontraumatic intracranial hemorrhage should focus on the arteries of the head and neck (up to the aortic arch). This protocol shows higher detection rate of concomitant anomalies of carotid and vertebral arteries. These findings are important for planning and successful performance of endovascular treatment for intracranial aneurysms.

Feasibility and intra-and interobserver reproducibility of quantitative susceptibility mapping with radiomic features for intracranial dissecting intramural hematomas and atherosclerotic calcifications

Quantitative susceptibility mapping (QSM) for 61 patients with dissecting intramural hematomas (n = 36) or atherosclerotic calcifications (n = 25) in intracranial vertebral arteries were collected to assess intra- and interobserver reproducibility in a 3.0-T MR system between January 2015 and December 2017. Two independent observers each segmented regions of interest for lesions twice. The reproducibility was evaluated using intra-class correlation coefficients (ICC) and within-subject coefficients of variation (wCV) for means and concordance correlation coefficients (CCC) and ICC for radiomic features (CCC and ICC > 0.85) were used. Mean QSM values were 0.277 ± 0.092 ppm for dissecting intramural hematomas and − 0.208 ± 0.078 ppm for atherosclerotic calcifications. ICCs and wCVs were 0.885–0.969 and 6.5–13.7% in atherosclerotic calcifications and 0.712–0.865 and 12.4–18.7% in dissecting intramural hematomas, respectively. A total of 9 and 19 reproducible radiomic features were observed in dissecting intramural hematomas and atherosclerotic calcifications, respectively. QSM measurements in dissecting intramural hematomas and atherosclerotic calcifications were feasible and reproducible between intra- and interobserver comparisons, and some reproducible radiomic features were demonstrated.

Efficacy and safety of low dose aspirin plus clopidogrel in the treatment of elderly patients with symptomatic intracranial artery stenosis.

As one of the most common causes of stroke, symptomatic intracranial artery stenosis (sICAS) is a great threat to public health, and its financial burden is substantial, with annual direct high medical costs particularly in China. Currently, the long-term use of conventional dual antiplatelet therapy (DAPT) as the primary modality of treatment for sICAS decreases the risk of stroke recurrence but increases the risk of bleeding. We aimed to evaluate the efficacy and safety of low dose aspirin plus clopidogrel for the treatment of sICAS in the elderly population. This randomized, controlled study included 181 older patients with transient ischemic attack (TIA) or ischemic stroke (IS) attributed to sICAS, who were recruited between April 2015 and November 2020. The 90 patients assigned to the low dose therapy group included aspirin, 75 mg, plus clopidogrel, 50 mg, daily for 90 and 91 patients assigned to the conventional group included aspirin, 100 mg, plus clopidogrel, 75 mg, daily for 90 days (aspirin or clopidogrel alone daily thereafter) were included in this intention-to-treat analysis. Efficacy and safety analyses were done in this trial. One hundred eighty-one eligible elderly patients with sICAS were enrolled in this trial. The median age was 70 years ranged 60-83 years. Seventy-five participants were with TIA and 106 with IS. The median time of follow-up was 30 months ranged 1-36 months. Ninety patients were assigned randomly to the low dose group and 91 patients to the conventional group. The rate of primary, secondary and composite efficacy were not significantly different between the low dose and conventional group (P > 0.05). The rate of composite safety outcome was 7.8% (7/90) in the low dose group, which was lower than 17.6% (16/91) in the conventional group (χ2 = 3.921, P = 0.048). At the time of last follow-up, 17 (9.4%) of 181 patients developed GI injuries, which occurred in four (4.4%) of 90 patients in the low dose group and in 13 (14.3%) of 91 patients in the conventional group (χ2 = 4.058, P = 0.044). The primary efficacy outcome occurred in six (18.2%) of 33 patients with severe sICAS and in 22 (38.6%) of 57 patients with moderate sICAS (χ2 = 4.064, P = 0.044) in the low dose group. In this study, the safety of low dose aspirin combined with clopidogrel proved to be equally efficient and significantly safer than those of conventional dose within 24 months in elderly patients with sICAS. However, the small size of this study limits the validity of the results. Further larger longitudinal and randomized controlled trials are necessary to evaluate the role of low dose DAPT in the patients with sICAS.

Abstract Number ‐ 182: Practical performance of stroke detection by Rapid and Viz.AI artificial intelligence applications.

Introduction Artificial intelligence applications for detecting ischemic strokes have recently been developed (Murray et al. 2020; Lotan 2021). Multiple applications exist that use proprietary algorithms to detect large vessel occlusions (LVOs) from CTA and CTP studies (Murray et al. 2020; Soun et al. 2021). These applications are intended to aid clinicians in diagnosing and triaging LVOs in anterior cranial arteries. Rapid (Ischemaview, Menlo Park, CA) and Viz.AI (Viz.AI, San Francisco, CA) are two such AI applications (Murray et al. 2020). The performance of both Rapid and Viz.AI in detecting LVOs in anterior circulation have been evaluated (Dehkharghani et al. 2021; Yahov‐Dovrat et al. 2021). These studies found Rapid and Viz.AI had high sensitivity (96% and 81% respectively) and high specificity (98% and 96% respectively) (Dehkharghani et al. 2021; Yahov‐Dovrat et al. 2021). In practice, CTA scans are sent to Rapid and Viz.AI for all patients suspected of having a stroke. We sought to evaluate the performance of Rapid and Viz.AI as they are used in practice, by measuring the performance of Rapid and Viz.AI LVO detection in cervical and intracranial arteries, in anterior cranial circulation, and in only extracranial and posterior vessels. Methods We used data from one large midwestern health system that uses both Rapid and Viz to conduct a retrospective cohort study to compare Rapid and Viz. We collected data from 672 patients that had CTA scans sent to both rapid and Viz between January 1st and December 31st. We manually abstracted from radiologists’ notes whether patients had an LVO in the vessels of the head and neck. We compared these data to records obtained from Rapid and Viz.AI of whether each application detected an LVO. We calculated the specificity and sensitivity of LVO detection for Rapid and Viz for all vessels evaluated in head and neck CTAs, for only the anterior intracranial vessels, and for only extracranial and posterior vessels. Results When including all vessels, Rapid had a sensitivity of 0.38 and specificity of 0.89, and Viz had sensitivity of 0.36 and specificity of 0.95. When including only anterior intracranial vessels, Rapid had a sensitivity of 0.62 and specificity of 0.89, and Viz had a sensitivity of 0.63 and specificity of 0.95. When including only extracranial and posterior vessels, Rapid had a sensitivity of 0.13 and sensitivity of 0.89, and Viz.AI had a sensitivity of 0.10 and specificity of 0.95. Conclusions We found specificity and sensitivity for Rapid and Viz.AI were lower than published, even when we restricted our analyses to the vessels in anterior circulation indicated for their use. Our study was not as rigorously controlled as other studies that have evaluated the performance of Rapid and Viz.AI, but we intended our results to evaluate the performance of these applications under actual use by clinicians. Our results suggest Rapid and Viz.AI could both aid in detecting anterior circulation clots, but radiologist interpretation of CTAs must still be relied upon to diagnose strokes, even in the anterior vessels for which their use is indicated.

Is there a correlation between dizziness and intracranial artery calcification?

This study aimed to investigate the correlation between dizziness and intracranial artery calcification. A total of 107 consecutive patients were recruited for this study. These patients were categorized into first (case) and second (control) groups. The first and second groups had complaints of dizziness and headache, respectively. All the patients had noncontrast cranial computed tomography images. Bilateral internal carotid arteries, bilateral vertebral arteries, and basilar arteries were evaluated for detecting burden of intracranial artery calcification. Finally, demographic characteristics, stroke risk factors, and burden of intracranial artery calcification of these two groups were compared. The Mann-Whitney U test, chi-square test, and Spearman's correlation were performed to analyze the study. It was found that the first and second groups included 39 and 68 patients, respectively. The mean age of the first group was significantly higher than that of the second group. The mean burden of intracranial artery calcification of the posterior circulation in the first and second groups were not statistically different from each other (p=0.555). The mean burden of intracranial artery calcification of the anterior circulation in the first group was found to be significantly higher than the second group (p=0.005). However, no significant difference was found between the two groups in terms of burden of intracranial artery calcification of anterior or posterior circulation, when the age variable was synchronized in both groups. Although this study found a limited correlation between dizziness and intracranial artery calcification, this situation was basically related to aging.

Abstract Number ‐ 108: Effect of Percutaneous Inferior Sympathetic Ganglion Block on Intracranial Artery Diameters on Cerebral Angiography

Introduction There is some data suggesting vasodilatory effect of sympathetic blockade in patients with aneurysmal subarachnoid hemorrhage but the effect on medium‐sized intracranial arteries remains unclear. Methods Serial ipsilateral intracranial angiograms were obtained before and after percutaneous inferior sympathetic ganglion block. The angiogram files were imported to a DICOM reader, Horos Open‐Source Medical Image Viewer (Version 3.3.6).The percent change of arterial diameter (compared with pre‐blockage image) was calculated in intracranial internal carotid (ICA), middle (MCA) and anterior cerebral (ACA) arteries. We also assessed the inter‐observer reliability of arterial diameter change using the Bland‐Altman method after two raters independently measured the arterial diameter in 2 images with a total of 12 arterial measurements. Results In Patient 1, there was an increase in diameter of intracranial ICA, MCA and ACA at 1 minute (9.62%, 10.34%, 8.64%), 5 minutes (11.38%, 12.22%, 14.42%) and 10 minutes (8.66%, 11.30%, 5.50%), respectively.In Patient 2, there was an increase in diameter at 1 minute (0.72%, 2.08%, ‐1.75%), 5 minutes (12.04%, 0.64%, 4.50%), 10 minutes (6.86%, 7.23%, 10.38%), 20 minutes (9.45%, ‐2.16%, 13.32%), and 30 minutes (7.31%, 12.02%, 6.50%), respectively. The Bland‐Altman coefficient of variation was 1.32 (range 0.01 ‐5.57) with majority (5 out of 6, 83%) of the data points within the upper and lower limits of acceptance. Conclusions We observed vasodilation in medium‐sized intracranial arteries ipsilateral to the percutaneous inferior sympathetic ganglion block as early as one minute post treatment and persisting for at least until 30 minutes post blockade.

Abstract Number ‐ 133: Intraventricular Pseudoaneurysm embolization in Moyamoya disease with NBCA

Introduction Moyamoya is a chronic occlusive cerebrovascular disease characterized by progressive steno‐occlusion of intracranial internal carotid arteries (ICAs) and their proximal branches (ACA, MCA) with development of hypertrophied collateralizing perforators. [1] Affected adults can suffer intraventricular hemorrhages (IVH) from ruptures of hypertrophic collaterals in some cases with formation of a pseudoaneurysm. [2,3] Pseudoaneurysms can be treated conservatively, by microsurgical clipping or endovascular embolization). Endovascular therapy allows easier reach and multiple treatment modalities (coiling, liquid embolization). [4‐7] Methods We present the case of a 44 year old male with Moyamoya disease who suffered a large IVH. Results The patient was brought to the ED after becoming unresponsive. A CT head showed diffuse subarachnoid and intraventricular hemorrhage. CTA revealed extensive Moyamoya disease with prominent hypertrophied ICA‐MCA perforator collaterals and irregular appearance of a right basal ganglia perforator, concerning for pseudoaneurysm. DSA showeda 4.2×3.3 mm pseudoaneurysm of a large hypertrophied perforator originating from the right ICA. A Magic 1.2 microcatheter was used over a 0.007” Hybrid microwire (both Balt, Montmorency, FR) to cannulate the perforator. A mixture of 3 cc of Lipiodol and 1 cc of n‐BCA (N‐butyl‐2‐cyanoacrylate) was injected in the aneurysm with care taken to avoid reflux into in the normal‐appearing portion of the vessel. The aneurysm was excluded from the circulation and post‐operative cone beam CT showed no evidence of large infarction or new intracranial bleeding. After several weeks of neurointensive care, the patient was discharged to rehab. Image description: A. CTA of the head demonstrating diffuse intraventricular hemorrhage (stars) and a spot sign in the territory of the right perforator collaterals concerning for aneurysm. B. DSA of the right internal carotid artery (ICA) demonstrating classic findings of moyamoya disease and a pseudoaneurysm (arrow) at the level of ahypertrophiedICA‐middle cerebral artery perforator collateral. C. Single shot X Ray of the glue cast within the aneurysm and adjacent portions of the vessel. The microcatheter tip is seen at the proximal end of the cast. D. Right ICA DSA after removal of the microcatheter demonstrates exclusion of the aneurysm from the circulation and sparing of adjacent perforator collaterals. Conclusions This abstract illustrates a rare case of pseudoaneurysm formation after rupture of a hypertrophied perforator collateral in a case of severe moyamoya disease. Treatment of these lesions should aim to exclude the aneurysm from the circulation and to preserve as much perforator as possible as these vessels supply normal parench This abstract illustrates a rare case of pseudoaneurysm formation after rupture of a hypertrophied perforator collateral in a case of severe Moyamoya disease. Treatment of these lesions should aim to exclude the aneurysm from the circulation and to preserve as much perforator as possible as these vessels supply normal parenchyma.

Abstract Number ‐ 98: Intravenous dose‐adjusted cangrelor use for neuroendovascular procedures: An institutional experience

Introduction The optimal antiplatelet therapy regimen for certain neuroendovascular procedures remains unclear. This study investigates the safety and feasibility of intravenous dose‐adjusted cangrelor in patients undergoing neuroendovascular procedures. Methods We conducted a retrospective chart review of all consecutive patients who underwent neuroendovascular procedures and were placed on intravenous cangrelor between September 1, 2020 and March 13, 2022. Cangrelor was administered as a 15 mcg/kg bolus followed by 2 mcg/kg/min infusion titrated to goal P2Y12reaction unit (PRU) level of 50 to 150, and then transitioned to oral antiplatelet therapy. Demographic characteristics, interventional variables, and clinical outcomes were collected. Results A total of 50 patients were included. The mean age (years) was 56.0±18.6, and 26 (52.0%) were males. Most patients were African American (n = 39/48, 81.3%). The most common comorbidities were hypertension (n = 25/49, 51.0%), active smoking status (n = 14/40, 35.0%), and prior ischemic stroke (n = 13/49, 26.5%). Intravenous thrombolysis was used in 4 patients (8.0%). Cangrelor infusion was used for the following procedures: embolization (n = 10/50, 20.0%), embolization and stent placement (n = 9/50, 18.0%), thrombectomy alone (n = 5/50, 10.0%), thrombectomy and stent placement (n = 10/50, 20.0%), and stent placement only (n = 14/50, 28.0%). Stent placement occurred intracranially beyond petrous segment of the internal carotid artery in 18 patients, remainder of internal or common carotid artery in 12 patients, and both intracranial and carotid arteries in 3 patients. PRU levels were measured in 48 patients (96.0%), with 26 patients (54.2%) achieving a PRU level of 50–150 greater than or equal to 50% of the time. Approximately 51.5% of the patients had a favorable functional outcome with modified Rankin Scale (mRS) score of 0 to 2 at 90 days (n = 17/33).During 1‐year follow up, approximately 4 patients had recurrent or new strokes (9.5%), 1 patient had in‐stent thrombosis (2.9%) and 1 patient with symptomatic intracranial hemorrhage [sICH] (2.4%), both while not on antiplatelet therapy, 2 patients with asymptomatic intracranial hemorrhage [ICH] (4.8%), and no gastrointestinal bleeding events were recorded. When stratified by PRU level, there were no significant differences in sICH (p = 0.841) or asymptomatic ICH (p = 0.853). Conclusions To our knowledge, this is the first report to demonstrate the safety and effectiveness of intravenous cangrelor use titrated based on platelet function testing in the largest cohort of patients who underwent neuroendovascular procedures to date. Further studies, including comparative studies to standard dose maintenance cangrelor, are necessary.