bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P319: Can Deep Learning Find the Ischemic Core on CT? Transfer Learning From Pre-Trained MRI-Based Networks
Authors: Yu Yannan , Christensen Soren , Xie Yuan , Gong Enhao , Lansberg Maarten G , Albers Greg , Zaharchuk Greg
Published: March 2021

Objective:
Ischemic core prediction from CT perfusion (CTP) remains inaccurate compared with gold standard diffusion-weighted imaging (DWI). We evaluated if a deep learning model to predict the DWI lesion from MR perfusion (MRP) could facilitate ischemic core prediction on CTP.

Method:
Using the multi-center CRISP cohort of acute ischemic stroke patient with CTP before thrombectomy, we included patients with major reperfusion (TICI score≥2b), adequate image quality, and follow-up MRI at 3-7 days. Perfusion parameters including Tmax, mean transient time, cerebral blood flow (CBF), and cerebral blood volume were reconstructed by RAPID software. Core lab experts outlined the stroke lesion on the follow-up MRI. A previously trained MRI model in a separate group of patients was used as a starting point, which used MRP parameters as input and RAPID ischemic core on DWI as ground truth. We fine-tuned this model, using CTP parameters as input, and follow-up MRI as ground truth. Another model was also trained from scratch with only CTP data. 5-fold cross validation was used. Performance of the models was compared with ischemic core (rCBF≤30%) from RAPID software to identify the presence of a large infarct (volume>70 or >100ml).

Results:
94 patients in the CRISP trial met the inclusion criteria (mean age 67±15 years, 52% male, median baseline NIHSS 18, median 90-day mRS 2). Without fine-tuning, the MRI model had an agreement of 73% in infarct >70ml, and 69% in >100ml; the MRI model fine-tuned on CT improved the agreement to 77% and 73%; The CT model trained from scratch had agreements of 73% and 71%; All of the deep learning models outperformed the rCBF segmentation from RAPID, which had agreements of 51% and 64%. See Table and figure.

Conclusions:
It is feasible to apply MRP-based deep learning model to CT. Fine-tuning with CTP data further improves the predictions. All deep learning models predict the stroke lesion after major recanalization better than thresholding approaches based on rCBF.
Abstract P321: The Cerebral Collateral Cascade: Rethinking the Assessment of Vascular Pathways in Acute Ischemic Stroke Patients
Authors: Faizy Tobias D , Mlynash Michael , Kabiri Reza , Christensen Soren , Kuraitis Gabriella , Mader Marius , Flottmann Fabian , Broocks Gabriel , Lansberg Maarten G , Albers Greg , Marks Michael , Fiehler Jens , Wintermark Max , Heit Jeremy
Published: March 2021

Background and Purpose:
Robust collateral blood flow in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO) has been correlated with favorable outcomes. Collaterals are commonly assessed by the number of arteries present on non-invasive CT angiography (CTA) overlying ischemic brain, but blood transit from these arteries through the brain tissue and the venous drainage is not assessed by this technique. We hypothesized that a comprehensive imaging analysis of the cerebral collateral cascade (CCC) would predict clinical and radiological outcomes in patients with AIS-LVO patients.

Materials and Methods:
Multicenter retrospective cohort study of AIS-LVO patients undergoing thrombectomy triage. CCC was determined on pre-treatment imaging by scoring for pial arterial collaterals, tissue-level collaterals (TLC), and venous outflow. Pial arterial collaterals were determined by CTA (Tan scale), TLC were assessed on CT perfusion data using the Hypoperfusion Intensity Ratio, and venous egress was assessed on CTA using the cortical vein opacification score system. 3 groups were defined: CCC+ (good pial collaterals, TLC, and venous perfusion), CCC- (poor pial collaterals, TLC, and venous perfusion) and CCCmixed (reminder of patients). Primary outcome was a good functional outcome (modified Rankin Scale [mRS] 0-2 at 90 days). Secondary outcome was final infarct volume.

Results:
647 patients met inclusion criteria: 176 CCC+, 345 CCCmixed and 126 CCC-. Multivariate ordinal logistic regression showed that CCC+ predicted good functional outcomes (mRS 0-2: OR=20.8 [95% CI 9.3-46.8]; p<0.001) compared to CCC- and CCCmixed. CCCmixed (β: 27.1, SE: 7.7; p<0.001) and CCC- (β: 86.6, SE: 9.9; p<0.001) profiles were associated with higher final infarct volumes after treatment compared to CCC+.

Conclusion:
Comprehensive assessment of the collateral blood flow cascade in AIS-LVO patients is a strong predictor of clinical and radiological outcomes in AIS-LVO patients.
Abstract P331: Accuracy of CT Perfusion Core Estimates for Predicting Infarct Size in the SELECT Study
Authors: Sarraj Amrou , Campbell Bruce , Sitton Clark , Christensen Soren , Khanpara Shekhar , Riascos Roy , Pujara Deep , Shaker Faris , Lansberg Maarten G , Albers Greg ,   On behalf of the SELECT Investigators
Published: March 2021

Background:
The accuracy of CT perfusion imaging for estimating the ischemic core has been questioned.

Methods:
In SELECT, a prospective cohort study of imaging selection, pts who achieved complete reperfusion after EVT were stratified on time from LKW to imaging acquisition and time from imaging to reperfusion. The difference between baseline CTP core volume and f/up infarct volume (on DWI after EVT) was classified as over-estimation (core >10 cc larger than infarct), adequate, or under-estimation (≥ 25 cc smaller). F/up DWI lesion was outlined using a semiautomated algorithm and co-registered to CTP.

Results:
Of 361 enrolled, 117 achieved TICI 3. F/up MRIs were acquired at 21 (13-30) hrs from EVT with median infarct volume of 16.4 cc, median 8.1 cc larger than baseline core. Median (IQR) time from imaging acquisition to groin puncture (GP) was 70 (50-95) min. Reperfusion was achieved at 35 (25-54) min of GP. The frequency of overestimation decreased as time LKW to imaging increased: < 90 min 6 (14%), 90 – 270 min 3 (6%) and > 270 min 1 (4%), and adequate estimation increased (< 90 min 21 (50%), 90 – 270 min 32 (65%) and > 270min 19 (73%), p for trend 0.048) Fig 1. Overestimation primarily occurred in pts imaged within 90 min who had short imaging to reperfusion times Fig 2. Volumetric correlation between pre-procedure and f/up imaging improved as LKW time to imaging acquisition increased; Spearman’s ρ: <90 min: 0.41 (p=0.007), 90-270 min: 0.35 (p=0.01), >270 min: 0.79 (p<0.0001). Spatially, overestimation occurred predominantly in white matter juxtacortical areas. Adjusting rCBF threshold from < 30% to < 20% in the 6 pts with overestimation ≤ 90 min from LKW resulted in adequate core estimation in all 6, Fig 3.

Conclusion:
In patients who achieve reperfusion, the correlation between baseline CTP ischemic core volume and f/up DWI volume improved as time LKW to imaging increased. Core estimation accuracy improved by using the < 20% CBF threshold for patients imaged within 90 minutes of LKW.
Abstract P334: Multiphase Computed Tomography Angiography-Perfusion for Quantitative Measurement of Ischemic Volumes
Authors: Chung Kevin J , Lee Donald H , Pandey Sachin , Goyal Mayank , Menon Bijoy K , Demchuk Andrew M , Khaw Alexander V , Mandzia Jennifer L , Lee Ting-Yim
Published: March 2021

Introduction:
Proficiency required to execute CT perfusion (CTP) protocols is a limiting factor in its use in acute stroke. We propose to calculate perfusion parametric maps and measure ischemic volumes using readily available non-contrast CT (NCCT) and multiphase CT angiography (mCTA) images.

Materials and Methods:
Twenty-five patients presenting with acute ischemic stroke were included in this study. Our proposed dynamic sequence (multiphase CT angiography-perfusion, mCTA-P) consisted of the NCCT as the pre-contrast baseline and three phases of mCTA, which corresponded to the peak arterial, peak venous, and late venous phases at 8 s intervals. CTP was acquired after mCTA and consisted of 22 dynamic images acquired over 60 s at 2.8 s intervals. A prototype model-based deconvolution algorithm (CT Perfusion 4D, GE Healthcare) was used to calculate cerebral blood flow (CBF) and Tmax maps for each series. Infarct was classified as voxels that satisfied both a time-dependent relative CBF threshold and Tmax > 8 s while penumbral voxels satisfied either threshold but not both.

Results:
Median (interquartile range) 24-hour follow-up infarct volume was 18.6 (4.7 to 34.3) ml and median stroke onset-to-CTP time was 124.0 (70.5 to 201.5) min. Bland-Altman analysis revealed good agreement between CTP and mCTA-P volume measurements as mean differences (limits of agreement) were -1.0 (-14.9 to 12.9) ml for infarct and 8.4 (-42.4 to 59.1) ml for penumbra. Intraclass correlation (95% confidence interval, p < 0.05) between CTP and mCTA-P volumes were 0.72 (0.46 to 0.87) for infarct and 0.68 (0.41 to 0.85) for penumbra, indicating good to moderate reliability.

Conclusion:
Quantitative perfusion can be estimated from NCCT and mCTA without introducing additional scan time, radiation dose, and contrast injections associated with CTP. Our technique allows assessments of early ischemic changes and collaterals to be augmented with quantitative perfusion measurements of ischemic volumes.
Abstract P337:
RAPID-LVO
for Automated Detection of Intracranial Large Vessel Occlusion in Ct Angiography of the Brain
Authors: Dehkharghani Seena , Lansberg Maarten G , Venkatsubramanian Chitra , cereda carlo W , Lima Fabricio O , Coelho Henrique , Rocha Felipe A , Qureshi Abid Y , Haerian Hafez D , Montalverne Francisco Jose , Copeland Karen , Heit Jeremy
Published: March 2021

Background:
Identification of large vessel occlusion (LVO) is paramount in the urgent evaluation of acute ischemic stroke (AIS). Emergent interpretation of large and high-complexity data sets, however, may impose strains upon imaging and clinical workflows, motivating development of fast and accurate computer-aided approaches to facilitate LVO detection in the emergency setting. This study investigates the performance of a fully automated LVO detection platform in a mixed cohort of stroke subjects with and without LVO on head and neck CT angiography (CTA).

Methods:
CTA from two cerebrovascular trials were enriched with cases from eleven global sites. Imaging and clinical variables were balanced between populations including in LVO positivity and across demographic and imaging environments to the extent achievable. Independent and fully blinded review for intracranial ICA or MCA M1 LVO was performed by two subspecialty neuroradiologists. A novel, user-independent imaging analysis application (
RAPID-LVO
, iSchemaview inc) was used to predict LVO presence, location, and overall performance relative to reader consensus. Any discordance between readers was adjudicated by a blinded tertiary reader with subspecialty training. Sensitivity, specificity, and receiver-operating characteristics were determined by an independent statistician. Performance thresholds were set a priori, including a lower bound of the 95% CI of sensitivity and specificity of ≥0.8 at mean times-to-notification <3.5 minutes.

Results:
217 CTA (median age 65.5, 53% male, 109 LVO(+)) were included. Lower confidence limits of sensitivity and specificity exceeded 90% (sensitivity 0.963, 95% CI 0.909-0.986; specificity 0.981, 95% CI 0.935-0.995), surpassing pre-specified performance benchmarks. Subgroup analyses revealed no decrement in performance relative to subject age or sex, vendor systems, or location of the examination within or outside the United States. The area under the receiver operating characteristics curve was 0.99 (95% CI: 0.971-0.999) and average time-to-notification was 3.18 minutes.

Conclusion:
RAPID-LVO
offers fast, highly accurate, and fully user-independent large vessel occlusion detection across all tested clinical and imaging environments.
Abstract P339: Evaluating Ga68 Regional Distribution as a New Pet Tracerfor Diagnosis Cerebral Amyloid Angiopathy
Authors: Zhang Qihui , Zhao Xiaobin , Kung Hank F , Yang Zhi , Zhu Lin , Lei Peng , Wang Shujing , Zhu Hua , Hong Haiyan , Duan Yunyun , Sun Li , Pan Jianwei , Meng Xiangxi , Zhao Xingquan , Demchuk Andrew M , Smith Eric , Wang Yongjun
Published: March 2021

Introduction:
The deposition of β-amyloid in cerebral vessels is an important sign of CAA. Recently, the 68Ga-P14-032 has been used in animal research. It has the ability to selectively bind a β on the cerebral vessel wall, and may become a tracer for CAA.

hypothesis:
We aimed to investigate the distribution of [
68
Ga]Ga-P14-032, a novel PET ligand that binds to vascular amyloid, in patients diagnosed clinically with probable cerebral amyloid angiopathy (CAA).

Methods:
This longitudinal cohort study of 7 subjects (2 probable CAA patients, 2 AD patients, 3 normal subjects) recruited from clinics in China. All participants were aged at least 55 years with underwent [
68
Ga]Ga-P14-032 PET/CT and PET/MR, a Montreal Cognitive Assessment (Moca) score on initial assessment. The brain PET/CT and PET/MR scans assessed through quantitative analysis. The mean cortical standardized uptake value ratio (SUVr) was calculated using cerebellum as reference. The cortex and white matter were segmented with ITK-Snap based on a T1-weighed image as the mask, leaving the scalp and the blood vessels out of the regions of interest. The corresponding PET volumes were extracted according to the masks obtained on MR and were fused with the MR images, using a MATLAB script. The images were read and interpreted by 2 doctors in nuclear medicine.Plasma levels of total-tau, amyloid-b40 and amyloid-b42 were measured by a single molecule array (Simoa) SR-X analyzer (Quanterix).

Results:
Positive expression can be seen in the pathological part of microvascular in 2 CAA patients of whom had an ICH. No significant signal was seen in AD subjects or controls. Plasma levels of total-tau, amyloid-b40 and amyloid-b42 were not different among the groups.

Conclusions:
Our results provide early evidence that the [68Ga]Ga-P14-032 PET probe binds preferentially to vascular amyloid, and may be a useful tracer to diagnostic of CAA. The PET marker was more sensitive to group differences than plasma assays of tau and amyloid.
Abstract P348: Perfusion Collateral Index vs. Hypoperfusion Intensity Ratio in Assessment of Angiographic Collateral Scores in Patients With Acute Ischemic Stroke
Authors: Tsui Brian , Chen Iris , Qiao Joe , Khatibi Kasra , Ponce Mejia Lucido , Liebeskind David S , Sharma Latisha K , Tateshima Satoshi , Bahr Hosseini Mersedeh , Colby Geoffrey , Nour May , Salamon Noriko , Saver Jeffrey , Jahan Reza , Duckwiler Gary , Nael Kambiz
Published: March 2021

Background and Purpose:
In acute ischemic stroke (AIS), perfusion imaging, while not directly visualizing collateral vessels, can provide important insight into collateral robustness, indexed by perfusion lesion volume and by perfusion lesion heterogeneity. Two proposed perfusion lesion heterogeneity measures indexing collateral status are the Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR), but their accuracy compared with direct collateral assessment on DSA has been incompletely characterized.

Methods:
Consecutive AIS patients with anterior circulation large vessel occlusion who underwent pre-endovascular thrombectomy MRI perfusion imaging were included. MRI measures analyzed were: 1) Perfusion Collateral Index (
PCI)
- the volume of moderately hypoperfused tissue (arterial tissue delay time between 2 and 6 seconds: ATD
2-6sec
) multiplied by its corresponding relative cerebral blood volume using Olea software; 2) Hypoperfusion Intensity Ratio (HIR) ratio of moderate TMax >6 s lesion volume versus severe Tmax >10 s lesion volume with the RAPID software program. DSA collateral scores were evaluated by ASITN grading and dichotomized to inadequate (ASTIN <2) vs. adequate (ASTIN ≥3).

Results:
Among 48 patients meeting entry criteria, age (mean ± SD) was 70 (± 15.2), 54% were female, and NIHSS (median, IQR) was 15 (10-19). For HIR, there was no significant difference in score values in patients with adequate vs inadequate collaterals: 0.35 ± 0.20 vs 0.39 ± 0.25, p=0.68. ROC analysis using previously described cut-off of 0.4 resulted in an AUC of 0.52 and sensitivity/specificity of 71% / 33%. For PCI, score values were significantly higher in patients with adequate vs inadequate collaterals, 117 ± 61 vs. 57 ± 41, p=0.002. ROC analysis using previously described cut-off of 62 resulted in an AUC of 0.8 and sensitivity/specificity of 84% / 78%.

Conclusion:
Collateral status can be accurately assessed on perfusion MRI with the Perfusion Collateral Index, which outperformed the Hypoperfusion Intensity Ratio. MRI-PCI is an informative imaging biomarker of collateral status in patients with AIS.
Abstract P350: Early Transcranial Doppler Velocity Changes as a Predictor for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage
Authors: Triano Matthew , Corbin Maite J , Desale Sameer , Liu Ai-Hsi , Felbaum Daniel R , Mai Jeffrey C , Armonda Rocco A , Aulisi Edward F , Chang Jason J
Published: March 2021

Introduction:
Although transcranial Doppler (TCD) evaluation for vasospasm remains an important study in aneurysmal subarachnoid hemorrhage (aSAH) management, its precise role in predicting delayed cerebral ischemia (DCI) remains unclear.

Hypothesis:
We evaluated optimal measures for evaluating TCD velocities and hypothesized that TCD velocity change would be the best predictor for DCI in patients with aSAH.

Methods:
Patients with aSAH over a two-year period were retrospectively analyzed. Baseline characteristics, outcomes, and TCD velocities in bilateral middle cerebral arteries (MCA) for hospital days 2 to14 were recorded. TCD variables, including absolute velocity and change in velocity, were obtained by creating a smoothing curve. A variable representing change in TCD velocity was then created through a linear regression model that confirmed greatest change in velocity associated with DCI occurred at days 2-7. Multivariate logistic regression analysis using DCI as outcome was then completed.

Results:
95 patients with aSAH were evaluated. Increased TCD velocity at days 2-7 proved to be a better predictor for DCI than absolute velocity with an optimal cutoff of 8.9 cm/sec/day (
p
= 0.019) and AUC 0.651. Multivariate logistic analysis using DCI as the outcome showed that poor admission Hunt-Hess scores (OR 5.02, 95%CI 1.22-22.67,
p
= 0.028) and increase in TCD velocity during days 2-7 (OR 5.32, 95%CI 1.41-23.33,
p
= 0.018) were independently associated with DCI.

Conclusions:
We found that relative increases in TCD velocities in the MCAs during the first 7 days (threshold increase of 8.9 cm/sec/day or 53.4 cm/sec from days 2-7) after aSAH were independently associated with DCI. Our findings suggest that vasospasm should be confirmed and treated aggressively when detected via increased TCD velocities during the first seven days in order to minimize DCI. This association requires independent confirmation.
Abstract P354: SWAN-DWI Mismatch Predicts Clinical Outcome After Mechanical Thrombectomy
Authors: Rusch Francois , Bracard Serge
Published: March 2021

Objectives:
Asymmetrically prominent veins on magnetic susceptibility sequences are thought to reflect the ischemic penumbra, by detecting high levels of desoxyheglobin. We investigated the relation between star-weighted angiography (SWAN)-diffusion weighted imaging (DWI) mismatch and clinical outcome after mechanical thrombectomy.

Methods:
We performed a retrospective study on patients who experienced anterior circulation stroke and for whom 1.5-Tesla MRI DWI and SWAN were performed upstream of mechanical thrombectomy. Mismatch was determined by using the Alberta Stroke Program Early CT Score (ASPECTS) on the diffusion-weighted and SWAN sequences. Three subgroups were defined in terms of mismatch level: high mismatch (HM), moderate mismatch (MM) and low mismatch (LM). Favorable outcome was defined as a modified Rankin score of 0-2 at three months. Multivariate logistic regression was used to examine associations between mismatch profiles and favorable outcomes.

Results:
The study included 108 patients who underwent mechanical thrombectomy. High mismatch was significantly associated with favorable clinical outcome (67% in the HM subgroup vs. 51% and 28% in the MM and LM subgroups respectively; odds ratio 1.25; 95 CI 1.02-1.56; p=0.037). No significant associations between SWAN-DWI mismatch and severe hemorrhagic complications or recanalization quality were brought to light by the present study.

Conclusion:
SWAN-DWI mismatch is a competent predictor of clinical outcome following mechanical thrombectomy.
Abstract P355: Real-Word Performance of Two Automated Software Platforms for Identification of Salvageable Tissue in Stroke Patients: A Single Center Experience
Authors: Katramados Angelos , Marin Horia , Kole Maximilian , Alsrouji Owais , Varun Pala , Miller Daniel J , Hefzy Hebah , Malik Shaneela , Ramadan Ahmad-Riad , Mitsias Panayiotis D , Rehman Mohammed , Brady Megan , Scozzari Dawn , Lewandowski Christopher A , Danoun Omar A , Grover Kavita , Newman Daniel , Barkley Gregory L , Chebl Alex B
Published: March 2021

Background and purpose:
Modern stroke treatment has been revolutionized by image-guided selection of patients for endovascular thrombectomy. Current automated platforms allow for real-time identification of large vessel occlusion and salvageable brain tissue. We sought to evaluate the performance of these platforms with regard to identification of infarcted and salvageable tissue.

Methods:
We studied all patients that presented to Henry Ford Health System hospitals over a period of 6 weeks, received CT perfusion imaging of the brain upon initial presentation. The images were processed with two automated software platforms. We prospectively measured volumes of tissue with cerebral blood flow (CBF) < 30% of contralateral hemisphere, Tmax >6 secs, and hypoperfusion indices (defined as the ratio of volumes Tmax>10 secs and Tmax>6 secs). We compared the outputs of the two platforms and analyzed the performance of each platform.

Results:
66 scans were included in our study. Both platforms were able to image all stroke patients within their FDA-approved indications. With regard to all scans, both platforms were noted to demonstrate comparable CBF<30% volumes (6.32 ml. vs 4.97 ml, p=0.276), and hypoperfusion indices (0.278 vs 0.338, p=0.344). However, there was statistically significant discrepancy in the volumes of tissue with Tmax>6 secs (23.96 vs 14.18 ml, p=0.023). Analysis of a subset of 12 scans, with evidence of LVO or severe symptomatic stenosis on corresponding CTA, showed again comparable CBF<30% volumes (12.84 ml vs 13.67 ml, p=0.725), and hypoperfusion indices (0.344 vs 0.314, p=0.699). However, the Tmax>6 secs volume discrepancy was greater and still statistically significant (75.54 ml vs 39.58 ml, p=0.048)

Conclusions:
Automated software platforms are an invaluable aid in the identification of salvageable tissue, and selection of patients for endovascular thrombectomy in the 6-24 hour window. However, the substantial difference in the identified volumes of hypoperfused tissue-at-risk may result in largely different clinical decisions and patient outcomes. Further validation efforts (and harmonization of algorithms) are required. Stroke teams should be aware of the limitations of automated analysis and need for expert review.
Abstract P361: Visualization of the Anterior Temporal Artery as a Predictor of Outcome in Middle Cerebral Artery Occlusion Patients Achieving Successful Recanalization After Interfacility Transfer
Authors: Parish Jonathan M , Stetler William R , Strong Dale , Prasad Tanushree , Rhoten Jeremy B , Karamchandani Rahul R , Bernard Joe D , Clemente Jonathan D , Defilipp Gary , Hines Andrew , Asimos Andrew W
Published: March 2021

Introduction:
Many non-thrombectomy centers lack Computerized Tomography Perfusion (CTP) capability. Anterior temporal artery (ATA) visualization on Computerized Tomography Angiography (CTA) has been previously associated with good outcomes in middle cerebral artery (MCA) occlusions, but not in the context of recanalization after interfacility transfer for thrombectomy. We hypothesized that independent functional outcome at 90 days would be greater for MCA occlusion patients initially presenting to non-thrombectomy centers with a visualized ATA on CTA who achieved TICI 2b or greater recanalization after transfer.

Methods:
We conducted a retrospective cohort study of patients transferred for mechanical thrombectomy. A neuroradiologist blinded to patient outcomes confirmed the MCA as the most proximal site of occlusion on CTA, and assessed for visualization of the ATA. TICI 2b or greater revascularization scores were confirmed by neurointerventionalists blinded to patient outcomes. Ninety-day mRS scores were obtained via telephone utilizing a structured questionnaire.

Results:
We identified a total of 107 MCA occlusion patients over a 3 ½ year period meeting our inclusion criteria. There were no significant differences in age, gender, race, comorbidities, median NIHSS, or time-to-revascularization variables between the ATA visualized (n=50) versus non-visualized (n=57) group, with the exception of significantly more wake-up strokes in the ATA visualized group (34.7% vs 16.1%, p=0.03). There was a non-significant trend for independent outcome (mRS ≤2) at 90 days for patients with ATA visualization compared to those for whom the ATA was not visualized on the CTA (63.8% vs 45.5%, p=0.06).

Conclusion:
For MCA occlusion patients initially presenting to non-thrombectomy centers achieving successful recanalization via mechanical thrombectomy, there is a strong trend for visualization of the anterior temporal artery on the CTA performed at the non-thrombectomy center as being a predictor of independent functional outcome. Especially for institutions without CTP capability, this association with ATA visualization should be further investigated as a predictor for good outcome after transfer for successful mechanical thrombectomy.
Abstract P39: Outcomes Across the Course of Recovery From Subarachnoid Hemorrhage
Authors: Neifert Sean , Schupper Alexander , Shuman William , Martini Michael , Chapman Emily , Oermann Eric , Mocco J D , MacDonald R Loch L
Published: March 2021

Introduction:
Data on progression of recovery after aneurysmal subarachnoid hemorrhage (aSAH) is rare and limited to small samples. We sought to characterize recovery after SAH in a secondary analysis of six SAH trials.

Methods:
Individual data on 3,717 patients from CONSCIOUS-1, ISAT, IHAST, trials of erythropoietin and statins, NEWTON-1, and NEWTON-2 was included. Outcome was described with the Glasgow Outcomes Scale (GOS). Proportions of GOS scores between the first and second time-point were compared using chi-square tests. Rates of improvement (final GOS > initial GOS), no change (final GOS = initial GOS), and worsening (final GOS < initial GOS) and the differences between initial and final GOS scores were calculated.

Results:
There were improvements in outcomes across the entire cohort (p<0.001) and from 30 days to three months (p<0.001), discharge to three months (p<0.001), six weeks to three months (p<0.001), and two months to one year (p<0.001). 907 (26%) of patients improved their outcome, while 2,228 (64%) had no change and 336 (9.7%) worsened. Of the 907 who improved, 773 (85%) improved by one GOS point, 128 (14%) improved by two points, and six (0.7%) improved by three points. Of patients with initial GOS scores of 2, 62 (38%) remained unchanged, while 91 (55%) improved and 11 (6.7%) died. Patient cohorts with initial WFNS grades of 1 (p<0.001), 2 (p<0.001), 3 (p=0.004), and 4 (p<0.001) improved their GOS scores.

Conclusions:
Across most time-frames, many SAH patients can be expected to recover, while a few will regress. Furthermore, even patients with the poorest initial neurological grades and outcomes showed improvement.
Abstract P398: Sex Differences in Stroke Frequency in Extracorporeal Cardio-Pulmonary Resuscitation for Refractory Cardiac Arrest
Authors: Balucani Clotilde , Canner Joseph K , Tonna Joseph E , Dalton Heidi , Choi Chun W , Whitman Glen J , Cho Sung-Min
Published: March 2021

Introduction:
Extracorporeal cardio-pulmonary resuscitation (ECPR) is being used more frequently for refractory cardiac arrest (rCA). Stroke remains a key determinant of outcomes in patients receiving ECPR. No studies have yet analyzed sex differences in the frequency of stroke in patients with rCA treated with ECPR.

Methods:
Retrospective analysis of ECPR cases for rCA identified in the Extracorporeal Life Support Organization (ELSO) International Registry. Age, sex, race/ethnicity and vascular risk factors were included. Stroke was defined as “Ischemic Stroke” and “Intracranial Hemorrhage” as detected by neuroimaging.
Statistical analysis:
level of significance was set to p≤0.05. To assess sex differences comparative tests were used as appropriate.

Results:
From 1992 to 2020 a total of 7,460 adult cases of ECPR for rCA were identified; 2,276 (30%) women vs. 5,184 (69%) men; Mean age 50.3 years (±SD 17) in women vs. 54.7 years (±SD 14) in men, (p<0.001). There was no significant difference in hypertension, diabetes, and atrial fibrillation frequency between men and women. Coronary artery disease was more frequent in men than women, 960 (18.5%) vs. 333 (14.6%) respectively (p<0.001). Intracranial hemorrhage occurred in 165 (2.2%) patients in the overall cohort, more frequently in women than men, 69 (3.0%) vs. 96 (1.8%) respectively (p=0.013). Ischemic Stroke occurred in 367 (4.9%) of the overall cohort and more frequently in men than women, 272 (5.2%) vs. 95 (4.1%) respectively (p =0.049). In-hospital mortality occurred in 89 (92.7%) men and 59 (85.5%) women with intracranial hemorrhage (p=0.133), and in 226 (83%) men and 76 (80%) women with ischemic stroke (p=0.497).

Conclusions:
This is the first study evaluating sex-related differences in the frequency of stroke in patients with ECPR from the largest contemporary ELSO registry. Women were younger than men at the time of rCI and had more intracranial hemorrhages. Men were older and had more ischemic strokes. Morality was high when stroke was present. Our study has implications for future development of sex-targeted treatment strategies when implementing ECPR to reduce neurological complications and to improve outcome.
Abstract P418: Stroke Admissions and Outcomes Among Cerebral Amyloid Angiopathy and Alzheimer’s Disease in the National Inpatient Sample
Authors: Nagaraja Nandakumar , Patel Urvish K
Published: March 2021

Background/Purpose:
Although cerebral amyloid angiopathy (CAA) and Alzheimer’s Disease (AD) can manifest as separate diseases it can co-exist due to shared amyloid β pathogenic mechanisms. We assessed admission rates and outcomes of ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) among hospitalized patients with a secondary diagnosis of AD and CAA.

Methods:
Adult patients discharged with a secondary diagnosis of CAA or AD in National Inpatient Sample (NIS) in the years 2016 and 2017 were identified. Admission rates for IS, ICH, and SAH were primary outcomes. In-hospital mortality and discharge to home were secondary outcomes. Multivariate logistic regression analysis was performed to evaluate secondary outcomes with model adjusted for demographics, medical history, hospital characteristics, and Elixhauser comorbidity index.

Results:
Among 60,609,519 admissions in NIS, 893,834 (1.5%) patients had a secondary diagnosis of AD [mean age 82.1 years and 62% women] and 14,850 (0.02%) patients had CAA [mean age 76.2 years and 51% women]. Combined AD+CAA was present in 1,335 (0.002%) patients. Compared to AD and controls (non AD or CAA), patients with CAA had higher admission rates for IS (11.5% CAA vs 2.8% AD vs 1.7% control, p<0.0001), for ICH (29.5% CAA vs 0.4% AD vs 0.2% control, p<0.0001) and for SAH (3% CAA vs 0.1% AD vs 0.1% control, p<0.0001). Among patients admitted for IS, discharge to home was less likely in AD compared to controls (10.4% AD vs 36.3% control, OR=0.40; 95%CI=0.36-0.44). Among patients admitted for ICH, discharge to home was less likely in AD compared to controls (6.3% AD vs 18.5% control, OR=0.57; 95%CI=0.41-0.78) but higher in CAA (17.8% CAA vs 18.5% control, OR=1.35; 95%CI=1.11-1.63). In-hospital mortality was less likely in patients with CAA than controls among patients admitted for ICH (9.6% CAA vs 23% control, OR=0.33; 95%CI=0.26-0.41) and SAH (6.7% CAA vs 19.1% control, OR=0.27; 95%CI=0.11-0.62).

Conclusion:
Admissions for IS, ICH, and SAH were higher among CAA compared to AD in NIS. CAA patients had lower in-hospital mortality for ICH and SAH admissions and higher rates of home discharge for ICH admissions. AD patients were less likely to be discharged home for IS and ICH admissions.
Abstract P419: A Systematic Characterization of Brain Endothelial Cell Death in Intracerebral Hemorrhage
Authors: Ikhsan Maulana , Zille Marietta
Published: March 2021

Introduction:
Intracerebral hemorrhage (ICH) is a type of stroke caused by the loss of vascular integrity leading to bleeding within the brain tissue. Hematoma-derived factors cause secondary injury mechanisms such as cell death days to weeks after the event and in regions distant from the primary insult. Increasing evidence suggests that hemoglobin released by the hematoma is one of the major contributors to neuronal injury in ICH. To date, it is unclear whether brain endothelial cells (EC) are similarly vulnerable to hemolysis products and undergo regulated cell death.

Hypothesis:
We hypothesized that brain EC undergo multiple, different modes of cell death after ICH and that the underlying mechanisms are different compared to neurons.

Methods:
We systematically investigated cell death mechanisms in brain EC after exposure to the hemolysis product hemin. We used chemical inhibitors of apoptosis, autophagy, ferroptosis, necroptosis, and parthanatos and assessed biochemical markers of these cell death modes.

Results:
Brain EC viability was concentration-dependently decreased, starting at higher hemin concentrations than neurons. Treatment of EC with ferroptosis inhibitors protective against hemin toxicity in neurons and against ICH in vivo showed that only N-acetylcysteine and deferoxamine protected brain EC, while ferrostatin-1 and U0126 did not abrogate EC death. The autophagy inhibitor bafilomycin A1 also reduced EC death and hemin increased the expression of the autophagy marker LC3. While inhibitors against apoptosis and parthanatos were not effective, the necroptosis inhibitor GSK872 demonstrated a partial protective effect.

Conclusions:
Our data suggest that ICH induces different mechanisms of death in EC (ferroptosis and autophagy) compared to neurons (ferroptosis and necroptosis) and may thus warrant a combinatorial therapeutic approach. Further investigations in human and ovine ICH brain tissue are ongoing.
Abstract P428: The Intracerebral Hemorrhage Score Overestimates Mortality in Young Adults
Authors: Maljaars Jason , Garg Aayushi , Molian Vaelan , Leira Enrique C , Adams Harold P , Shaban Amir
Published: March 2021

Introduction:
The intracerebral hemorrhage (ICH) score is a widely used scoring system for predicting mortality in patients with ICH. This score has been validated for use in adults of all ages with ICH, but not specifically for use in populations of young adults (age 18-45). We aimed to determine the validity of the ICH score when applied to young adults with ICH.

Methods:
This was a retrospective analysis of all patients aged 18-45 with spontaneous ICH consecutively admitted to our institution from 2009-2019. We calculated the ICH score for each patient, recording the individual subcomponents, and analyzed the scores for prediction of mortality at 30 days. We also analyzed the individual subcomponents of the score for effect on mortality.

Results:
We identified 156 patients (mean age 35 +/- 7.8; 67 were female, 103 were white) to include in our study. The 30-day mortality rate was 15% (n=24); these patients had a mean age of 34.9 +/- 7.8, compared to survivors who had mean age 35.4 +/- 7.8 (p=0.797). ICH scores were predictive of mortality (p=0.036 for trend); however, the actual mortality rates in our population were substantially lower than those predicted by the ICH score. Specifically, patients in our population with scores of 1, 2, or 3 had 30-day mortality rates of 0%, 3%, and 41%, compared to the current ICH score mortality predictions of 13%, 26%, and 72%, respectively. Scores of 4 and 5 in our population were more closely aligned to current ICH predictions (85% and 100% compared to 97% and 100%, respectively). Of the ICH score subcomponents, ICH volume >30mL (p=0.007) and Glasgow Coma Scale (GCS) scores of 3 or 4 (p=0.014) were the strongest predictors of mortality at 30 days.

Conclusion:
The ICH score is predictive of mortality for adults of all ages, but the specific mortality rates associated with this scoring system vary considerably when applied to young adults (age 18-45). This over-estimation should be taken into consideration when applying the predictions of the ICH score to young adults with ICH; additionally, special attention should be given to ICH volume >30mL and very low GCS scores, as these were the strongest predictors of early mortality.
Abstract P461: Contemporary National Estimates of Characteristics and Outcomes Associated With Supra and Infratentorial Intracerebral Hemorrhage
Authors: Niravath Marilyn , Meeks Jennifer , Potter Thomas , Pan Alan , Khan Osman , Misra Vivek , Woo Daniel , Ziai Wendy C , Hanley Daniel F , Britz Gavin W , Vahidy Farhaan S
Published: March 2021

Introduction:
Location specific Intracerebral Hemorrhage (ICH) characteristics and outcomes are important for risk stratification and clinical trial design. However, they have not been described at the population level.

Methods:
We analyzed the National Inpatient Sample (90% of US hospitalizations) from 09/2015 to 12/2017 and utilized ICD-10 codes to identify ICH patients with a primary diagnosis of either supra-tentorial (ST) or infra-tentorial (IT) hemorrhage; excluding intraventricular or unspecified location. Utilizing sampling weights, nationally representative proportions of ST and IT ICH patients across demographic, comorbidity, healthcare utilization, disease acuity and outcomes are provided. We fit survey design logistic regression models for in-hospital mortality (IHM) and home discharge (HD). Odds Ratios (OR) and 95% confidence Intervals (CI) are reported.

Results:
Across the analysis time period, a total of 161,395 ICH patients were identified, of whom 51,025 (31.6%) and 20,135(12.5%) had ST and IT ICH respectively. IT ICH patients (vs. ST ICH) were younger (66.9 vs. 67.9 years), with higher proportions of Black (19.1% vs. 17.6%) and un-insured (5.9% vs. 4.7%). A significantly greater proportion of IT ICH patients had prior myocardial infarction, congestive heart failure, atrial fibrillation, renal disease and hypertension. Whereas the prior cerebrovascular disease, dementia, depression and alcohol abuse was associated with ST ICH. Smaller proportion of IT ICH patients (vs. ST ICH) were treated in urban teaching hospitals (81.4% vs. 83.2%). A greater proportion of IT ICH underwent invasive mechanical ventilation (58.1% vs. 46.7%), ventriculostomy (18.2% vs. 10.2%), and tracheostomy (6.4% vs. 4.6%). The total charges and charges per day were significantly higher for IT ICH patients. The overall IHM was 22.6%. A greater proportion of IT ICH patients (vs. ST ICH) experienced IHM (28.2% vs. 17.3%) and smaller proportion had HD (16.7% vs. 20.7%). In the fully adjusted models, IT ICH was associated with a significantly higher IHM (OR, CI: 1.47, 1.26 - 1.71) and lower likelihood of HD (OR, CI: 0.56, 0.46 - 0.68).

Conclusion:
ST and IT ICH patients have distinctive risk factor and demographic profiles. IT ICH is associated with poor outcomes.
Abstract P467: Clinical Effectiveness of Endovascular Stroke Treatment in the Early and Extended Time Windows
Authors: Nogueira Raul , Haussen Diogo C , Liebeskind David S , Jovin Tudor G , Gupta Rishi , Saver Jeffrey L , Jadhav Ashutosh , Budzik Ron , Baxter Blaise W , Krajina Antonin , Bonafe Alain , Malek Ali R , Ana Paula Narata , Mohammaden Mahmoud , Zhang Yanchang , Morgan Patricia , Ji Minyi , Bartolini Bruno , English Joey , Albers Gregory , Mlynash Michael , Lansberg Maarten G , Michael Frankel , Pereira Vitor , Veznedaroglu Erol
Published: March 2021

Background and Purpose:
The clinical efficacy of mechanical thrombectomy (MT) has been unequivocally demonstrated in multiple randomized clinical trials (RCTs). However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. We aim to assess the clinical effectiveness of MT by comparing the specific RCT populations with corresponding patient cohorts derived from a prospective registry.

Methods:
A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label MT registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials based on the age, baseline NIHSS, occlusion site, IV tPA use, pre-morbid mRS and time to treatment criteria used in the RCTs without considering specific parenchymal imaging findings. Baseline and outcome variables were compared across the corresponding groups.

Results:
As compared to the treated patients in the actual trials, registry-derived patients tended to be younger and had lower baseline ASPECTS. In addition, time to treatment was earlier and the use of IV tPA and general anesthesia were higher in DAWN- and DEFUSE 3-registry derived patients versus their corresponding trials. Reperfusion rates were higher in the registry patients. The rates of 90-day good outcome (mRS 0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding RCTs (SWIFT-Prime, 64.5% vs 60.2%; DAWN, 50.4% vs 48.6%; Beyond-DAWN: 52.4% vs 48.6%; DEFUSE 3, 52% vs 44.6%, respectively; all P>0.05). Registry-derived patients had significant less disability than the corresponding RCT controls (ordinal mRS shift OR, P <0.05 for all).

Conclusion:
Our study provides favorable generalizability data for the safety and efficacy of thrombectomy in the “real-world” setting and supports that patients may be safely treated outside the constraints of RCTs and strict guidelines.
Abstract P470: Annual Endovascular Treatment Procedural Volume and One Year Mortality in Acute Ischemic Stroke
Authors: Kim Jun Yup , Lee Keon-Joo , Kang Jihoon , Kim Beom Joon , Kim Seong-Eun , Park Hong-Kyun , Cho Yong-Jin , Park Jong-Moo , Lee Kyung Bok , Lee Ji Sung , Lee Juneyoung , Yang Ki Hwa , Hong Ock Ran , Shin Ji Hyeon , Bae Hee-Joon
Published: March 2021

Background:
In-hospital and 30-day mortality, 3-month functional outcome were reported as associated with endovascular treatment (EVT) case volume per hospital, but one-year mortality was unknown. Furthermore, the hospital EVT volume threshold based on one-year mortality was not reported. We aimed to investigate whether there was a correlation between annual EVT case volume per hospital and one-year mortality and suggest volume threshold.

Methods:
Data from Korean national survey for assessing quality of acute stroke care were used. The survey was conducted since 2005 and the subject was patients with acute stroke who were admitted via emergency rooms within 7 days of onset at hospitals treating 10 or more stroke cases during the three (2013, 2014) or six (2016) month survey period. Ischemic stroke cases treated with EVT during the last available three assessments (2013, 2014, and 2016) were selected for the analysis.

Results:
A total of 1,746 ischemic stroke cases (age, 69.2 ± 12.4years; male, 56.6%) treated in 120 hospitals with EVT were analyzed. The median annual EVT case volume was 12.0 cases per hospital (interquartile range, 6.0-22.9) and the mortality at one-month, three-month, and one-year were 12.7%, 16.6%, and 23.3%, respectively. When divided into quartiles according to the annual EVT case volume, the lowest quartile group was found to have the highest one-year mortality (odds ratio [95% confidence intervals], 1.49 [1.04-2.13]), adjusted for age, sex, NIHSS, onset to arrival time. Restricted cubic splines performed on the annual EVT case volume per hospital revealed that cut-off value for the probability of one-year mortality was 15 cases per year (
p
<0.02) (Figure).

Conclusions:
There was an association between annual EVT case volume and one-year mortality, and the volume threshold per hospital based on the one-year mortality was found to be 15 EVT cases per year.
Abstract P485: Predictors and Clinical Impact of Deep Grey Matter Infarction After Endovascular Treatment for Large Vessel Occlusion Stroke: Results From the Escape-NA1 Trial
Authors: Ospel Johanna , Hill Michael D , Kashani Nima , Mayank Arnuv , Singh Nishita , Cimflova Petra , Marko Martha , Nogueira Raul G , McTaggart Ryan A , Demchuk Andrew M , Poppe Alexandre Y , Zerna Charlotte , Joshi Manish , MENON Bijoy K , Almekhlafi Mohammed , Tymianski Michael , Goyal Mayank
Published: March 2021

Purpose:
In this post-hoc analysis of the ESCAPE-NA1 trial, we investigated the prevalence of deep grey matter infarcts and their influence on clinical outcome.

Methods:
Infarcts on 24 hour follow up imaging (non contrast head CT or diffusion-weighted MRI) were categorized as predominantly deep grey matter infarcts (caudate and/or lentiform nucleus infarcts with sparing of the superficial grey matter and white matter) vs. other infarcts. Total infarct volume was manually segmented in all patients. When MRI follow-up was available, deep grey matter and grey matter infarct volumes were segmented separately. Multivariable logistic regression with adjustment for key minimization variables and by infarct volume was used to assess the association of predominantly deep grey matter infarcts and good outcome.

Results:
Of the 1026 included patients, 316 (30.8%) had predominantly deep grey matter infarcts. Cumulative proportions of good outcome for overall, grey matter, deep grey matter, and superficial grey matter infarct volumes are shown in the figure. Good outcomes were more frequently achieved in patients with predominantly deep grey matter infarcts (239/316 [75.6%] vs. 374/704 [53.1%]). Deep infarcts were tightly correlated with infarct volume (Pearson rho -0.35) and in multivariable analysis deep grey matter infarcts were predictive of outcome overall; when examined in volume percentiles, there was no effect of deep infarct location.

Conclusion:
Predominantly deep grey matter infarcts are associated with good outcomes. Deep grey matter infarct location favorable prognosis is associated with small overall infarct size.