bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract Number ‐ 232: Carotid Webs as an Under‐Reported Etiology of Acute Ischemic Stroke – Current Diagnostic Challenges
Authors: Dawod Giana , Bouslama Mehdi 
Published: April 2023

Introduction
Carotid webs are anatomical variants in the internal carotid artery vasculature that predispose patients to stroke. As of now, optimal treatment has yet to be established given the lack of large, randomized trials. Part of this stems from the fact that carotid webs remain under‐recognized sources of ischemic stroke despite a high rate of reoccurrence. Herein, we aim to shed light on the diagnosis with our respective center’s experience as well as discuss diagnostic challenges associated with carotid webs.

Methods
We present a case of a 40‐year‐old male with no past medical history who presented to our center after having developed sudden onset left sided weakness and sensory loss, a left homonymous hemianopia, and dysarthria. Vessel imaging confirmed a right middle cerebral artery occlusion, specifically in the M2 segment, in the setting of a right carotid web.

Results
Once intracerebral hemorrhage was ruled out, tissue plasminogen activator was administered, with improvement in neurologic exam. Mechanical thrombectomy was thus deferred. Review of the MRI brain showed that in addition to an infarct in the right subinsular white matter region, there were scattered multifocal right hemispheric acute to early subacute infarcts raising concern for an underlying embolic etiology. While the right M2 occlusion looked like it had mainly resolved, a new focal non‐occlusive intraluminal thrombus was found in the right carotid bulb on CTA, MRA, and carotid ultrasound, just distal to a small transverse extraluminal carotid web (Figure 1). The decision was made to take the patient for right carotid stenting given that the carotid web served as a high‐risk lesion. A stent was placed in the right carotid artery with no complications, and the patient was continued on dual antiplatelet therapy. Upon being seen in outpatient clinic after discharge, patient had NIHSS score of 0, with no residual deficits, and was continued on DAPT and a statin for secondary stroke prevention.

Conclusions
Knowing that patients with carotid webs are at increased risk for stroke, recognition and accurate diagnosis of webs is crucial for appropriate treatment. Diagnostic challenges of carotid webs should be highlighted to prevent misdiagnosis. These include heightened awareness of the patient population that is most at risk, radiographic mimics, location of the lesion as a confounder, and rule out of other stroke etiologies. Prompt recognition of this high‐risk vascular lesion using multiple imaging modalities at different time points during the patient’s admission allowed for treatment of the underlying etiology of his stroke. By increasing awareness on the appropriate diagnostic approach for carotid webs, more information can be garnered to elucidate optimal treatment strategies.
Abstract Number ‐ 241: Simultaneous IV tPA During Thrombectomy Reduces Post‐Procedure Hypoperfusion Volumes in Anterior LVO Patients
Authors: Ribo Marc , Garcia‐Tornel Alvaro , Olivé‐Gadea Marta , Requena Manuel , Rizzo Federica , Rodrigo Marc , Pagola Jorge , Juega Jesus , Muchada Marian , Rodriguez‐Luna David , Rodriguez‐Villatoro Noelia , Molina Carlos , Rubiera Marta 
Published: April 2023

Introduction
Simultaneous tPA administration during mechanical thrombectomy may induce synergistic benefits (1). We aimed to characterize the hypoperfusion status after thrombectomy according to the timing of tPA administration and the degree of final recanalization.

Methods
We studied consecutive anterior circulation large vessel occlusion (LVO) stroke patients treated with mechanical thrombectomy who received a CT perfusion (CTP) immediately after endovascular procedure (2). Patients were divided in three groups according to: no iv tPA treatment (non‐tPA), tPA administration before 120 minutes (tPA>120) or iv tPA administration within 120 min (tPA< 120) of groin puncture. The extend of post‐procedure hypoperfusion (volume Tmax>6s) and relative hypoperfusion reduction compared with admission CTP (volume post‐procedure – admission Tmax>6s/admission Tmax>6s) according to final TICI scores were compared between the three study groups.

Results
One hundred and sixty‐nine patients were included in the study, mean age 72 years and median baseline NIHSS of 15. Thirty (17.8%) patients received iv tPA more than 2h before groin puncture (tPA>120), 32(18.9%) within 2h of the puncture (tPA < 120) and 107(63.3%) were non‐tPA. No difference on stroke severity, pre‐procedure hypoperfusion volume or occlusion location before thrombectomy were detected between groups. The rate of complete recanalization (TICI 3, 38.5%) was also similar in the 3 study groups (p = 0.12). Overall, the post‐procedure hypoperfusion volume was significantly lower in the tPA< 120 group (19.9±4.6cc vs 35.0±5.5, p = 0.04), and the relative hypoperfusion reduction was higher in tPA< 120 (0.86 vs 0.66, p = 0.05) as compared to non‐tPA. No significant differences were detected between non‐tPA and tPA>120 groups. For each final TICI score the post‐procedure hypoperfusion tended to be lower in the tPA< 120‐group, with a stronger reduction in patients with lower degree of recanalization (Figure).

Conclusions
A reduction of post‐thrombectomy hypoperfusion volumes was detected in patients treated with iv tPA during or shortly before thrombectomy, which could be a surrogate marker of the beneficial effect of tPA on the microcirculation. The specific reperfusion synergistic effect of tPA and mechanical thrombectomy beyond LVO recanalization warrants future studies.
Abstract Number ‐ 245: Machine Learning‐Enabled Detection of Unruptured Cerebral Aneurysms Improves Detection Rates and Clinical Care
Authors: Ali Iman J , Salazar‐Marioni Sergio A , Abdelkhaleq Rania , Niktabe Arash , Giancardo Luca , Love Christopher J , Paz Dan , Bibas Orin , Segev Omri , Sheth Sunil A 
Published: April 2023

Introduction
Unruptured cerebral aneurysms (UCAs) have a relatively low prevalence of approximately 3%, but detection can prevent devastating consequences of subarachnoid hemorrhage. Here, we assess the performance of a machine‐learning (ML) algorithm to identify UCAs and determine whether routine use of the algorithm would have improved detection rates and patient care.

Methods
From a prospectively maintained multi‐center registry across 8 certified stroke centers (1 comprehensive, 7 primary), we identified patients who underwent CT angiogram for evaluation of stroke from 3/14/21 – 11/31/21. An FDA‐cleared convolutional deep neural network (Viz ANEURYSM, Viz.ai, Inc.) trained to identify UCAs at least 4mm analyzed the images. Ground truth was provided by independent expert neuroradiology read. The primary outcome was rate of UCAs detected by the ML algorithm but not detected or addressed in the clinical radiology report or clinical notes, which was determined by two independent researchers.

Results
Among 1191 CT angiogram scans performed during the study period, 49 were flagged by the ML algorithm as possibly demonstrating an UCA, of which 26 cases were confirmed as true positive (PPV 53%).The most common locations included posterior communicating artery (22%), followed by MCA bifurcation (19%). Of these cases, 9 (35%) were not noted in the clinical radiology report or clinical notes, with a median size of 4.2 mm [IQR 3–7.5 mm], and 22 (85%) were not referred for follow up, with median size of 5 mm [IQR 3.7‐11.3 mm]. Of the 22 cases not referred for follow up, 13 (59%) had been noted in the radiology report. 46% (6/13) of the detected but not referred cases had a diameter greater than 10mm.

Conclusions
UCAs of sizes and intra‐dural locations that may warrant treatment are frequently missed or not followed up in routine clinical care. An ML algorithm that flags studies and notifies clinicians may minimize missed treatment opportunities.
Abstract Number ‐ 248: Association Between Vertebrobasilar Stenosis, Location, and Quantitative Magnetic Resonance Angiography Flow State
Authors: Ballout Ahmad A , Ballout Ahmad A , Schneider Julia R , Black Karen , Sideras Panagiotis , Huang Brendan , Katz Jeffrey M , Libman Richard B 
Published: April 2023

Introduction
The relationship between the degree of vertebrobasilar stenosis and QMRA distal‐flow status is uncertain. Our aim was to investigate this relationship.

Methods
We retrospectively reviewed patients who presented with acute ischemic stroke, had neurovascular imaging demonstrating ≥ 50% stenosis of extracranial or intracranial vertebral or basilar arteries, and QMRA within one year of stroke, between 2009 and 2021 at two institutions. The WASID and CAVATAS methods were used to measure the degree of intracranial and extracranial vertebrobasilar stenosis, respectively. Patients were grouped as: high‐grade (≥ 70% stenosis) in (1) one vertebral artery; (2) two vertebral arteries; or (3) basilar artery; and (4) moderate grade (≤70% stenosis) in either intracranial vertebral and basilar arteries or exclusive extracranial vertebral stenosis or occlusion. QMRA distal‐flow status was used to dichotomize patients into low‐flow and normal‐flow states based on VERiTAS criteria. P‐values were calculated using chi‐squared analysis and Fisher exact test with statistical significance defined as p < 0.05.

Results
Of the 303 patients undergoing QMRA for vertebrobasilar disease, 69 met study inclusion, consisting of 31 patients with low‐flow and 38 patients with normal‐flow states. High‐grade stenosis was most commonly found in one vertebral artery (34.8%), followed by both vertebral arteries (29.0%), and the basilar artery (27.5%), and moderate stenosis or exclusive extracranial disease made up 21.7% of patients. High‐grade stenosis in at least one vertebral or basilar artery was significantly associated with low‐flow states compared to patients with moderate‐grade stenosis or exclusive extracranial disease (53.7% versus 13.3%, p = 0.007). High‐grade stenosis in both vertebral arteries was significantly more likely to result in a low‐flow state compared to high‐grade stenosis in one vertebral artery (75.0% versus 41.7%, p = 0.001) or to high‐grade stenosis in the basilar artery (75.0% versus 42.1%, p = 0.040).

Conclusions
Low distal flow status on QMRA is strongly associated with high‐grade intracranial stenosis compared to moderate‐grade or exclusive extracranial stenosis and is nearly twice as frequent with high‐grade intracranial stenosis of both vertebral arteries compared to one. The location, degree of stenosis, and distal‐flow status should be considered as possible entry points for future prospective treatment trials in intracranial atherosclerotic disease.
Abstract Number ‐ 249: Differential Ischemic Vulnerability depicted by White Matter‐Sparing Infarction following Alteplase Recanalization
Authors: Ballout Ahmad A , Patel Krishna , Saad Ayesha , Parikh Krutee , Libman Richard B 
Published: April 2023

Introduction
Gray and white matter possess different ischemic thresholds and therefore will undergo infarction at different rates of cerebral blood flow. We present a patient that presented with a large vessel occlusion and recanalized following alteplase administration within hours of symptom onset. Follow‐up imaging revealed a white matter‐sparing infarction, visually depicting the differential ischemic vulnerability between gray and white matter.

Methods
Case Report.

Results
An 83‐year‐old woman with a medical history of dementia, hypertension, and atrial fibrillation, not on anticoagulation due to recent gastrointestinal hemorrhage, presented with speech difficulty and right sided weakness. Her blood pressure was elevated at 170/86 and neurological exam demonstrated mixed aphasia, right homonymous hemianopia, left gaze deviation, and dense right hemiparesis with a National Institutes of Health Stroke Scale of 23. Non‐contrast CT of the head showed a hyperdense left terminal internal cerebral artery (ICA) and was otherwise unremarkable (Figure 1, A). CT angiography of the head and neck revealed an ICA “T” occlusion with no flow seen at the ICA terminus, the left anterior cerebral (A1) and middle cerebral (M1) segments (Figure 1, B). She was treated with intravenous alteplase 132 minutes from when she was last known normal. She was transferred to our comprehensive stroke center for mechanical thrombectomy, however, catheter angiography showed spontaneous recanalization of left ICA (Figure 1, C). Brain MRI the following day showed a white matter‐sparing infarction involving the left ICA territory (Figure 1, D‐F). She was discharged to rehab with moderate improvement in her aphasia and right hemiparesis.

Conclusions
This case visually depicts the differential ischemic vulnerability between gray and white matter since recanalization likely occurred at a cerebral blood flow level below the gray matter ischemic threshold while remaining above the white matter threshold. While pretreatment ischemic core volumes are inversely correlated with functional outcomes after recanalization of large vessel occlusions,1 selective white matter‐sparing infarction on post‐treatment MRI is associated with more favorable outcomes.2 Predicting ischemic core volume with perfusion imaging using the same CBF threshold for both gray and white matter may over‐estimate the ischemic core if CBF is between the gray and white matter thresholds.
Abstract Number ‐ 258: Effect of COVID‐19 Vaccination on COVID‐19 associated Stroke: A Propensity‐Matched Case‐Control Study
Authors: El‐Seblani Nader , Nagaraja Nandakumar 
Published: April 2023

Introduction
Coronavirus disease 2019 (COVID‐19) vaccines have demonstrated efficacy in protecting against severe respiratory distress, averting hospitalization and long‐term sequelae of COVID‐19 infection. The study aimed to determine the effect of COVID‐19 vaccination on mortality and complications due to COVID‐19 associated acute ischemic stroke (AIS).

Methods
Using TriNetX COVID‐19 research database, patients who had received full vaccination from December 1, 2020, to April 30, 2021, and later had AIS within 30 days of COVID‐19 infection during the period from June 1, 2021, to November 30, 2021, were identified. A control group with unvaccinated COVID‐19 patients with AIS was identified in the same study period. The two groups were matched for demographics and comorbidities with 1:1 propensity score matching. All‐cause mortality was the primary outcome while intracranial hemorrhage (ICH) and venous thromboembolism (VTE) were secondary outcomes at 30 days.

Results
During the study period, 21814 patients were admitted with AIS within 30 days of COVID‐19 diagnosis: 21233 patients were unvaccinated while 581 patients were vaccinated before their AIS. After propensity score matching, 581 patients in both groups were balanced for relevant characteristics. Patients fully vaccinated prior to acquiring COVID‐19‐associated AIS had lower rates of all‐cause mortality [6.9% (40/581) vs 10.7% (62/581), P = 0.02, hazard ratio = 0.62; 95% confidence interval = 0.41, 0.92)], ICH (3.1% vs 6.9%; OR 0.44, p = 0.005) and VTE (2.9% vs 7.9%; p = 0.0007) when compared with unvaccinated patients.

Conclusions
Within the limitations of retrospective observational study, prior vaccination for COVID‐19 is associated with improved one‐month survival and reduced complications after COVID‐19 associated AIS.
Abstract Number ‐ 260: Endovascular Thrombectomy for Acute Ischemic Stroke with Acute Cancer: Updated Meta‐analysis
Authors: Jhou Hong‐Jie , Yang Li‐Yu , Chen Po‐Huang , Lee Cho‐Hao 
Published: April 2023

Introduction
Acute cancer is associated with poorer prognosis and death in patients with acute ischemic stroke (AIS).1 Endovascular treatment has shown to be effective and safety treatment (EVT) for AIS with large vessel occlusion2; however, the effect of acute cancer on outcomes secondary to EVT in patients with AIS remains unclear.

Methods
We searched PubMed, Embase, as well as Cochrane for all relevant literature until June 1, 2022. Random‐effects model was used to estimate outcomes including good functional outcome, successful reperfusion, mortality at 3‐month, and symptomatic intracerebral hemorrhage. The heterogeneity of outcomes was assessed using the Cochran Q test and I2 statistics.

Results
Of the 12 studies, a total of 5,944 patients with AIS were enrolled. 389 (6.5%) patients had acute cancer. A quarter of patients regained functional independence after EVT. Compared with patients without acute cancer, those with acute cancer following EVT had similar rate of successful reperfusion (76.9% versus 72.6%; OR, 0.90; 95% CI, 0.63–1.30; I2 = 27%; p = 0.18; Figure 1A) and did not increase the risk of symptomatic intracerebral hemorrhage (6.0% versus 7.7%; OR, 0.85; 95% CI, 0.51–1.42; I2 = 0%; p = 0.45; Figure 1B). However, patients with acute cancer had more functional dependence (28.2% versus 42.3%; OR, 0.53; 95% CI, 0.41–0.67; I2 = 1%; p = 0.43; Figure 1C) and death at 3‐month (39.3% versus 18.6%; OR, 3.64; 95% CI, 2.35–6.27; I2 = 64%; p < 0.01; Figure 1D) than those without acute cancer.

Conclusions
The results of study showed that patients with acute cancer and AIS had a higher risk of functional dependence and mortality than those without acute cancer despite successful reperfusion and no increment in the occurrence of symptomatic intracerebral hemorrhage. Only 28.2% of patients with acute cancer regained functional independence, so physicians and patients should consider whether to use EVT for patients with acute cancer. There remained the need for further randomized control studies for better clinical evidence.
Abstract Number ‐ 264: Examining The Impact Of Area Deprivation On Patient Outcomes In LVO AIS
Authors: Abdelkhaleq Rania , Dongarwar Deepa , Salazar‐Marioni Sergio , Niktabe Arash , Tariq Muhammad B , Sheth Sunil A 
Published: April 2023

Introduction
The Area Deprivation Index (ADI) is a validated neighborhood‐level measure that utilizes variables such as income, education, and employment to quantify relative socioeconomic disadvantages. Here we explore the impact of disparities on EVT access.

Methods
From our prospectively maintained multi‐hospital registry, we identified patients with LVO AIS from January 2019‐ June 2020. Patient addresses and zip‐codes were validated using US Postal Service codes and matched to census‐tract level ADI scores that were obtained from Neighborhood Atlas. ADI were categorized into high and low using the median ADI as the cuto!. The primary outcome was utilization of EVT and IV tPA and was determined using multivariable logistic regression and expressed as OR [95% CI]. All p‐values are two‐sided with p < 0.05 defined as statistically significant. All analyses were conducted using RStudio (Version 1.2.5001).

Results
Among 637 patients with LVO AIS, median age was 68, 46% were female, 53% were white, 27% were black, and 78% identified as Hispanic. Median state ADI was 5 IQR [5]. NIHSS was similar between low/high ADI (mean(SD): 13.3(7.75) vs 13.6(8.62), p‐value 0.69) regions. ADI was significantly associated with race (6.41 vs 4, black vs. white, p‐value 0.03). In the univariable analysis, patients treated with EVT had lower mean ADIs (5.2 vs. 4.6, no EVT vs. EVT, p< 0.02). In multivariable analysis adjusted for age, sex, race, ethnicity and NIHSS, higher ADI was significantly associated with greater rates of IV tPA usage (OR 1.7 [1.01‐ 2.98]) but not EVT usage (OR 0.63 [0.04‐1.0])

Conclusions
Patients residing in disadvantaged neighborhoods may have reduced rates of reperfusion therapy, despite comparable acute stroke presentation symptoms. These findings are consistent with prior studies demonstrating poorer health outcomes in these populations.
Abstract Number ‐ 266: Focal Cerebral CNS Vasculitis due to SARS‐CoV‐2 Infection
Authors: Reyes Cleo Zarina A , Villar Manny , Cheponis Kathryn E , Yacoub Hussam A 
Published: April 2023

Introduction
Several neurological manifestations of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, including anosmia, encephalopathy, and stroke, have been reported. We report a case of a 42‐year‐old man presenting with ischemic stroke due to cerebral vasculitis in the setting of SARS‐CoV‐2 infection.

Methods
Case report

Results
A 42‐year‐old man, recently diagnosed with SARS‐CoV‐2 infection, presented with nonfluent aphasia and right‐sided hemiparesis that started five hours prior. Neurological examination revealed nonfluent aphasia, right‐sided facial palsy, and hemiparesis. Computed tomography (CT) of the head showed left‐sided caudate infarct and early ischemic changes in the left putamen. CT angiography (CTA) revealed occlusion of the proximal left M1 segment. Patient’s symptoms rapidly improved and mechanical thrombectomy was not pursued. Patient was started on dual antiplatelet therapy with aspirin and clopidogrel. Magnetic resonance imaging (MRI) of the brain showed acute infarcts in the left posterior parietal, lentiform nucleus, and frontal cortex. CT of the chest revealed bilateral subsegmental pulmonary emboli. Patient was discharged on apixaban and atorvastatin daily, with mild residual aphasia. A month later, the patient returned with dysarthria and right‐sided paresthesia that began three hours prior. CTA showed severe left proximal M1 stenosis involving a longer segment. He was started on vasopressor. Symptoms resolved within 24 hours with residual mild aphasia. MRI brain revealed multiple foci of cortical infarcts within the left MCA territory with no diffusion/ perfusion mismatch. MRA head showed further pruning of the distal MCA branches within the left sylvian fissure with severe stenosis along the mid‐M1 and minimal flow anteriorly, with contrast enhancement at the site of the stenosis, suggestive of vasculitis. Autoimmune vasculitis panel was unremarkable. Due to suspicion of focal inflammatory vasculopathy related to recent SARS‐CoV‐2 infection, patient was started on intravenous methylprednisolone 1 gram daily for 5 days followed by a prednisone taper. MRA revealed improved blood flow in the left middle cerebral artery and branches. The was discharged on apixaban, aspirin, atorvastatin, and a prednisone taper with mild residual aphasia.

Conclusions
To our knowledge, this is the first reported case of CNS vasculitis associated with an underlying SARS‐CoV‐2 infection with radiographic improvement of blood flow in the affected vessel within 4 days of treatment with high‐dose steroids. This case supports the use of high‐dose steroids in patients with CNS vasculitis associated with SARS‐CoV‐2 to prevent further stroke burden.