bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract WP47: Combined Treatment of Rt-PA With Mechanical Thrombectomy is Associated With Better Outcome Than Mechanical Thrombectomy Alone and Possibly Underutilized - A National Inpatient Sample Study
Authors: Nagaraja Nandakumar , Kubilis Paul , Hoh Brian L , Kelly Adam G
Published: June 2021

Background and Purpose:
2015 AHA/ASA guidelines recommend mechanical thrombectomy (MT) with rt-PA for eligible patients within 6 hours of acute ischemic stroke (AIS). We evaluated the real world impact of the guidelines by analyzing trends and outcomes of stroke patients discharged from 2012 to 2016 in National Inpatient Sample database.

Methods:
Patients discharged with primary diagnosis of AIS were identified with ICD-9 codes for 2012 to third quarter of 2015 and ICD-10 codes for 2016 and last quarter of 2015. Patients who received only rt-PA, only MT, rt-PA+MT or no treatment were analyzed for discharge outcomes including length of stay (LOS), inpatient mortality and discharge status to home. Survey procedures were used for analysis. Multivariable regression analysis with pairwise comparison of treatment groups with no treatment group was performed to evaluate outcomes controlling for risk factors and all patient refined DRG severity of illness and risk of mortality scores.

Results:
A total of 2,290,520 adult AIS patients were in the study with mean age 70.4 years (SE 0.03) and 51.1% (SE 0.08) women. There was a significant increase in treatment with rt-PA (5.86% in 2012 to 7.67% in 2016, OR=1.07, 95% CI 1.05-1.08); and MT (0.55% in 2012 to 1.75% in 2016, OR=1.38, 95%CI 1.31-1.45); but not combination rt-PA+MT (0.54% in 2012 to 0.57% in 2016, OR=1.04, 95% CI 0.99 - 1.08). LOS was significantly reduced for rt-PA (mean 6.07 days in 2012 to 4.91 days in 2016, p<0.0001, 1.7 percent reduction/year), and rt-PA+MT (mean 9.19 days in 2012 to 7.10 days in 2016, p=0.0067, 2.9 percent reduction/year) but not for MT alone (9.61 days in 2012 to 8.51 days in 2016, p=0.50). The odds of patients discharged home was significantly higher by 8%, 9% and 15% among patients who received rt-PA (p<0.0001), MT (p=0.0095) and rt-PA+MT group (p=0.0004), respectively, compared to those who did not receive treatment. There was no significant change in inpatient mortality between the groups.

Conclusion:
The utilization of MT increased but that of rt-PA+MT remained unchanged from 2012 to 2016. Patients with AIS have better LOS and discharge disposition to home when treated with rt-PA+MT than MT alone. Combined treatment of rt-PA with MT may be underutilized in clinical practice.
Abstract WP472: Improving Neurologic Follow-Up After Stroke Utilizing a Nurse Practitioner
Authors: Dashefsky Larry , Hren Carol , Munici Tiffanie , Richardson Melissa
Published: June 2021

Background:
Patients who experience acute ischemic stroke are at increased risk for a secondary vascular event. Risk factor management as well as review of the medication regimen are important components to secondary prevention. Neurologic follow-up is an essential step during transitions of care to ensure these components are addressed. For a variety of reasons, stroke patients do not always complete follow up appointments. The literature suggests that such patients are at increased risk for readmission.

Purpose:
The purpose of this project was to improve access to neurologic follow-up for patients diagnosed with acute ischemic stroke after discharge from an acute care or rehabilitation setting. The secondary goal was to decrease readmission rates.

Methods:
A nurse practitioner (NP) was added to the inpatient stroke neurology service. The model of care was redesigned with the NP performing subsequent assessments after the initial evaluation was completed by the neurologist. The NP also organized the plan of care, including appropriate post discharge follow-up. Over time, due to challenges with access to appointments, the NP started an outpatient stroke clinic. Data were entered into Get With The Guidelines®-Stroke to identify the patients who had a neurology provider appointment scheduled prior to hospital discharge, regardless of discharge disposition.

Results:
Between the first quarter of 2018 and the second quarter of 2019, the percentage of patients with a neurologic follow-up appointment scheduled prior to hospital discharge improved from 23% to 61%. During this same time period, the readmission rates decreased from 14% to 9%.

Conclusions:
Adding the NP position to an inpatient stroke neurology service and using this role to lead an outpatient stroke clinic improves the percentage of patients who have appointments scheduled prior to hospital discharge. Improving access to follow-up care influences readmission rates.
Abstract WP479: Associations Between Vascular Risk, Amyloid Burden and Incident Dementia: The ARIC-PET Study
Authors: Gottesman Rebecca F , Wu Aozhou , Coresh Josef , Jack Clifford R , Knopman David S , Rahmim Arman , Sharrett A. R , Wagenknecht Lynne , Walker Keenan , Wong Dean , Mosley Thomas H
Published: June 2021

Background:
Midlife vascular risk factors (MVRF) are associated with incident dementia. Similarly, amyloid β(Aβ) and neurodegeneration (e.g.brain volumes), as parts of the Alzheimer’s Disease (AD) ATN framework, are associated with cognition. Whether vascular and AD-associated factors contribute to dementia independently or interact synergistically to reduce cognitive ability is not well understood.

Methods:
Recruited from 3 U.S. communities, ARIC-PET participants were followed from 1987-89 (45-64 yo) through 2016-17 (74-94 yo). Cognition was evaluated in 2011-13 (ages 69-88), and twice more, every 2-3 years. In 2011-13, nondemented ARIC-PET participants had a brain MRI, with measurement of white matter hyperintensities (WMH) and brain volumes, with florbetapir (Aβ) PET scans in 2012-14; global cortical standardized uptake value ratio (SUVR) was log-transformed and standardized. Dementia was classified by expert review, as well as phone and medical record surveillance. The relative contributions of vascular risk (MVRF, WMH volume) and AD pathology (elevated Aβ SUVR, smaller AD signature region volumes) to incident dementia were evaluated with Cox proportional hazards regression.

Results:
In 298 individuals, 36 developed dementia. In models with key MVRF, demographics, and Aβ SUVR, hypertension and Aβ each independently predicted dementia risk (per SD of Aβ SUVR: HR 2.57, 95% CI 1.72-3.84; hypertension: HR 2.57, 95% CI 1.16-5.67), but didn’t interact on dementia risk. WMH (per SD: HR 1.51, 95% CI 1.03-2.20) and Aβ SUVR (per SD: HR 2.52, 95% CI 1.83-3.47) each contributed to incident dementia but WMH lost significance when MVRF were added to the model. Smaller AD signature regions were associated with incident dementia, independent of Aβ SUVR, and remained significant after adjustment for MVRF (HR per SD 2.18, 95% CI 1.18-4.01).

Conclusions:
Midlife hypertension and late-life Aβ independently contribute to dementia risk, but don’t synergize on a multiplicative scale. Neurodegeneration (e.g.smaller AD signature region volume) is also associated with incident dementia, independent of Aβ and MVRF. Multiple pathways leading to dementia should be considered when evaluating risk factors and interventions to reduce the burden of dementia.
Abstract WP494: Neuroimaging Correlates of Apathy in Late-Onset Depression
Authors: Samotaeva Irina S , Avedisova Alla S , Zakharova Kseniya V , Arkusha Inna A , Luzin Roman V , Akzhigitov Renat G , Guekht Alla B
Published: June 2021

Apathy is prevalent in older depressed patients and considered to be a predictor of increased dementia risk. Neuroimaging characteristics of late-life depression are being discussed. However, it is unclear whether apathetic (ApD) and nonapathetic depression (D) have different neuroimaging correlates. The objective of this study was to examine structural and functional bases of ApD by using morphometric and functional connectivity MRI analyses. We enrolled 45 consecutive patients with late-onset depression (85% female; mean age=66 (4) years, mean education=14 (2) years) and 22 age and gender-matched healthy elderly. Patients were divided into ApD (n=26) and D (n=19) groups based on Apathy Scale scores. All the participants underwent 1.5 T structural MRI and resting-state fMRI. Fazekas scale was used to quantify white matter hyperintensities. Demographic data, Hamilton Depression Rating Scale (HAMD), Apathy Scale, and MoCA scores for the three groups were compared. Association between apathy, depression and neuroimaging characteristics was assessed using regression analysis with demographic and cognitive variables included as covariates. ApD patients demonstrated nonsignificantly higher HAMD and Fazekas scores and lower MoCA scores compared to D patients. The latter group showed similar Fazekas and slightly lower MoCA scores vs healthy elderly. After controlling for covariates, apathy was significantly associated with volumes of nucleus caudatus and putamen on the right as well as functional connectivity between anterior cingulate and parahippocampal gyrus. Depression correlated with the volumes of the cerebral and cerebellum cortices as well as functional connectivity of salience resting state network. Our study demonstrated an association between volumes of basal ganglia, functional connectivity of anterior cingulate and apathy in late-onset depression.
Abstract WP495: Sex Differences in Cognitive Decline: A Pooled Cohort Analysis of ARIC, CARDIA, CHS, FOS, NOMAS
Authors: Levine Deborah A , Gross Alden L , Briceño Emily M , Tilton Nicholas , Kabeto Mohammed U , Hingtgen Stephanie M , Giordani Bruno J , Sussman Jeremy B , Hayward Rodney A , Burke James F , Elkind Mitchell S , Manly Jennifer J , Tom Sarah E , Sacco Ralph L , Wright Clinton B , Gottesman Rebecca F , Gaskin Darrell J , Sidney Stephen , Yaffe Kristine , Galecki Andrzej T
Published: June 2021

Background:
Sex differences in dementia risk are unclear but some have found greater risk for women. We hypothesized that women have greater cognitive decline than men, after adjusting for potential confounders.

Objective:
Determine associations between sex and cognitive decline.

Methods:
We pooled data from 19,378 participants free of stroke and dementia (mean [SD] age 59.8 [10.4] years at first cognitive assessment), of whom 8,654 (44.7%) were men and 3,852 (19.9%) were black, from 5 longitudinal cohorts between 1971 and 2017: Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, and Northern Manhattan Study. The primary outcome was change in global cognition. Secondary outcomes were change in memory and executive function. Linear mixed-effects models measured changes in each continuous cognitive outcome over time by sex, adjusted for demographics, education, vascular risk factors, and age*follow-up time, race*follow-up time, systolic blood pressure*follow-up time, and use of antihypertensive medication*follow-up time interaction terms. Cognitive outcomes were set to a t-score metric (mean 50, standard deviation [SD] 10) at a participant’s first cognitive assessment; a 1-point difference represents a 0.1 SD difference in the distribution of cognition across the 5 cohorts. Median follow-up was 12.4 (IQR: 5.9, 21.0) years.

Results:
Women had significantly higher baseline performance than men in global cognition, executive function, and memory (adjusted differences in intercepts, 2.09 to 2.15 points; all P<0.001) (
Figure
). Compared with men, women had significantly faster declines in global cognition, executive function, and memory (adjusted differences in slopes, 0.04 to 0.06 points per year faster;
P
<0.001) (
Figure
).

Conclusion:
These results are consistent with women having greater cognitive reserve but faster cognitive decline than men.
Abstract WP497: Investigation of Cognitive Impairment in Ischemic Stroke Patients After Endovascular Treatment in Acute Phase and at 6 Months Follow-Up
Authors: Nakagami Toru , Suda Satoshi , Aoki Junya , Kanamaru Takuya , Muraga Kanako , Suzuki Kentaro , Nishimura Takuya , Kutsuna Akihito , Numao Shinichiro , Nishiyama Yasuhiro , Kimura Kazumi
Published: June 2021

Purpose and Objective:
There have been limited reports that focused on cognitive impairment in acute ischemic stroke after endovascular treatment. The aim of this study, therefore, was to investigate cognitive function in patient after endovascular treatment in acute phase and at 6 months follow-up.

Method:
In this prospective study, from December 2016 to November 2018, the patients who were diagnosed as ischemic stroke with occlusion of the internal carotid artery and of the middle cerebral artery and treated with endovascular treatment were enrolled. Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA-J) test within 5 days of onset and at 6 months follow-up. We defined cognitive impairment as a score of <24 in MoCA-J.

Results:
150 patients were enrolled. MoCA-J was feasible in 69 patients (median 76 years; 49 female) (46%), in acute phase (Figure A). 63 patients (91%) had cognitive impairment and no significant differences were found in the naming and the abstraction domains between MoCA-J <24 group and ≧24 group. At 6 months follow-up, 48 patients (median 72 years; 12 female) were assessed with MoCA-J and 35 patients (73%) had cognitive impairment. However, only one patient scored less at 6 months follow-up than in acute phase (Figure B), which resulted in the significant increase in the median MoCA-J score (7 vs. 21, P<0.05) (Figure C) and in all the domains except for the language (P=0.078) (Figure D).

Conclusion:
In acute phase of ischemic stroke after endovascular treatment, MoCA-J was feasible in about 45%, in which 91% had cognitive impairment. However, at 6 months follow-up, the median MoCA-J score was significantly higher and less number of patients had cognitive impairment. The present results suggest that cognition recovers with time after endovascular treatment in ischemic stroke.
Abstract WP498: Impaired Pericyte Constriction and Cerebral Blood Flow Autoregulationin Diabetes
Authors: Liu Yedan , Wang Shaoxun , Guo Ya , Zhang Huawei , Roman Richard , Fan Fan
Published: June 2021

Diabetes is the primary pathological factor attributed to Alzheimer’s disease and vascular cognitive impairment. Previous studies demonstrated that hyperglycemia promoted oxidative stress in the cerebral vasculature. Cerebrovascular pericytes contribute to maintaining blood-brain barrier (BBB) integrity and regulating cerebral blood flow (CBF). However, whether hyperglycemia diminishes the contractile capability of pericytes, impairs CBF autoregulation and increases BBB permeability are unclear. In the present study, we examined the role of pericytes in cerebrovascular function and cognition in diabetes using cell culture
in vitro
, isolated penetrating arterioles
ex vivo
and CBF autoregulation
in vivo
. Reactive oxygen species were elevated in high glucose (HG, 30 mM) treated vs. normal glucose (NG, 5.5 mM) treated pericytes. Further, mitochondrial superoxide production was increased in HG-treated vs. NG-treated group (13.24 ± 1.01 arbitrary unit (a.u.)/30min vs. 6.98 ± 0.36 a.u./30min). Mitochondrial respiration decreased in HG-treated vs. NG-treated pericytes (3718 ± 185.9 pmol/min/mg, n=10 vs. 4742 ± 284.5 pmol/min/mg, n=10) as measured by a Seahorse XFe24 analyzer. HG-treated pericytes displayed fragmented mitochondria in association with increased fission protein (DRP1) and decreased fusion protein (OPA1) expression. HG-treated pericytes displayed lower contractile capability than NG-treated cells (20.23 ± 7.15% vs. 29.46 ± 9.41%). The myogenic response was impaired in penetrating arterioles isolated from diabetic rats in comparison with non-diabetic rats. Autoregulation of CBF measured by a laser Doppler flowmeter was impaired in diabetic rats compared with non-diabetic rats. Diabetic rats exhibited greater BBB leakage than control rats. The cognitive function was examined using an eight-arm water maze. Diabetic rats took longer time to escape than the non-diabetic rats indicating learning and memory deficits. In conclusion, hyperglycemia induces pericyte dysfunction by altering mitochondrial dynamics and diminishing contractile capability, which promotes BBB leakage, decreases CBF autoregulation and contributes to diabetes-related dementia.
Abstract WP501: Recanalization of the Occluded Carotid by Endovascular and Hybrid Interventions
Authors: Zanaty Mario , Roa Jorge , Samaniego Edgar , Hasan David
Published: June 2021

Introduction:
Patients with medically refractory COICA (chronically occluded internal carotid artery) have an annual stroke risk of 5%-7%, can suffer from cognitive impairment, refractory hypertension, and have decreased quality of life.

Methods:
We reviewed the literature on interventions for COICA patients to assess the risks/benefits after recanalization via endovascular techniques (ETs) or hybrid surgery [ET plus carotid endarterectomy] (HS). Carotid occlusion was defined as 100% stenosis based on DSA. Chronicity was defined as ≥ 1 month of documented occlusion of the ICA. We used the Hasan et al grading system for COICA classification.

Results:
The rate of successful recanalization varied from 60-100%, and that of complications from 0-21.75%. Both rates were classification dependent: for type A and B, the successful recanalization rate using ET was 100.00% with a 5.00% complication rate. For type C, the success rate for ET was 44.44% with a complication rate of 44.44%; however, for the HS, developed to treat specifically type C, the success rate was 88.73% with a major complication rate of 5.66% and a minor complication rate of 7.04%. For type D, the success rate was 25% with a 12.5% complication rate. Successful recanalization leads to an improvement in the neurological symptoms with control of the recurrent ischemic symptoms in 88.0%. Failure to recanalize lead to recurrent T.I.As/strokes 30 days post-procedure in 40% of the patients. Successful recanalization leads to a reversal of systolic hypertension, which was maintained at follow-up in 85.71% (23/27) patients. Bradycardia occurred in 62% (36/69) of ET of COICA, and in 0% of HS, and was classification dependent: 90% of type A, 80% of type B, 44% of type C and 44% of type D. Successful recanalization resulted in symmetrical perfusion between the 2 hemispheres, resolution of penumbra, normalization of the MTT and improvement in MoCA score.

Conclusion:
Type A and B benefited from ET. Type C can benefit from HS. Type D did not benefit from any intervention. A phase 2b randomized controlled trial is needed
Abstract WP51: Preoperative Light Transmission Aggregometry Values Predict Thromboembolic Complications After Stent-Assisted Coil Embolization
Authors: Kan Issei , Ishibashi Toshihiro , Sakuta Kenichi , Fujimura Soichiro , Yuki Ichiro , Kaku Shogo , Kodama Tomonobu , Kato Naoki , Nishimura Kengo , Aoki Ken , Sasaki Yuichi , Karagiozov Kostadin , Murayama Yuichi
Published: June 2021

Background:
Control of risks of thromboembolic complications (TEC) during stent assisted coil embolization (SACE) for unruptured intracranial aneurysm (UIA) is crucial for outcome. We evaluated retrospectively our cohort of SACE for UIA, analyzing the role of anatomical, clinical and stent type related factors to determine optimal presurgical values of light transmission aggregometry (LTA) for TEC prevention.

Methods:
From July 2015 to May 2018 we retrospectively analyzed 132 SACE treated UIA patients at our hospital. Aneurysm location and maximum diameter, preoperative LTA-value, ischemic and hemorrhagic complications, preoperative and discharge Modified Rankin scale (mRS) were collected. Aspirin 100 mg and clopidogrel 75 mg were started 7 days before operation, with “boost” therapy (additional 75mg clopidogrel in LTA-value >60) added after August 2016, addressing clopidogrel resistance. After multivariate analysis we developed our original combined parameter called TEC predictor (TEP). Receiver operating characteristic (ROC) analysis for TEP and each significant variable were performed.

Results:
TEC were confirmed in five (3.8%, 5/132) and hemorrhagic - in nine patients (6.8%, 9/132), with mRS deterioration post-operatively in five patients (5/132, 3.8%). By multivariate analysis, LTA-value and maximum diameter were chosen as significant variables, and included in TEP. ROC analysis of LTA-value showed sensitivity and specificity of 0.866 and 0.600 respectively (AUC=0.747) with cut-off point of 62. TEP permitted establishing optimal LTA-value according to the aneurysm maximum diameter to predict TEC. Neuroform-EZ, Enterprise, Neuroform-Atlas, and LVIS stents complications were 2.9%, 10.5%, 1.4%, and 14.3%, respectively.

Conclusions:
Preoperative LTA-value contributes to predicting TEC after SACE of UIA. TEP (relating LTA cutoff value to aneurysm size) provides improved antiplatelet therapy adjustment prior to SACE for TEC reduction.:
Abstract WP54: National Trends in Utilization and Outcomes of Endovascular Treatment in Acute Ischemic Stroke Patients in Pre- and Post-Stent Retriever Era in the United States
Authors: Chaudhry Saqib A , Hassan Ameer E , Akhtar Iqra N , Chaudhry Mohammad Rauf A , Huang Wei , Digala Lakshmi P , Suri Fareed K , Zafar Werdah , Gomez Camilo R , Siddiq Farhan , Qureshi Adnan I
Published: June 2021

Introduction:
Several studies have shown improved outcomes in ischemic stroke patients treated with mechanical thrombectomy in clinical trials after introduction of stent retrievers. The outcomes of patients undergoing endovascular treatment in general practice are expected to improve. We performed this analysis to evaluate trends in utilization of endovascular treatment in acute ischemic stroke and associated rates of death and disability in real world practice.

Methods:
We obtained data for patients admitted with primary diagnosis of ischemic stroke in United States from 2009-2016 using Nationwide Inpatient Sample. We determined the rate and pattern of utilization, and associated in-hospital outcomes of endovascular treatment among them. Outcomes were classified as minimal disability, moderate to severe disability, and death based on discharge disposition and compared between two time periods: 2009-2011 and 2013-2016 to represent pre and post stent retriever approvals in United States.

Results:
Of the 3,780,955 patients admitted with ischemic stroke, 244,092 (6.46%) received intravenous thrombolytic treatment, and 48,409 (1.28%) underwent endovascular treatment. There was a fourfold increase in patients who underwent endovascular treatment (0.55% of ischemic strokes in 2009 vs. 2.03% in 2016, trend p < 0.001). In multivariate logistic regression analysis, adjusted for age, gender, thrombolytic therapy, in hospital complications including secondary intracranial hemorrhages, the rate of none to minimal disability improved between the two study intervals (2009-2011 versus 2013-2016), odds ratio (OR) 1.82, 95% confidence interval (CI) 1.47-2.67, p=<0.0001) and moderate to severe disability decreased (OR 0.56, 95% CI 0.45- 0.70, p= <0.0001). There was significant decrease inpatient mortality for patients treated during 2013-2016; OR 0.67, 95% CI 0.56- 0.79, p= <0.0001).

Conclusion:
There has been a significant increase in the proportion of acute ischemic stroke patients receiving endovascular treatment with improvement of outcomes. Our analysis support generalizability of the successful results observed in clinical trials of endovascular treatment in the post-stent retriever approval era in United States.
Abstract WP60: Absence of Hyperdense Middle Cerebral Artery Sign, as Measured on the Hounsfield Scale, Predicts Poor Functional Outcome and May Indicate Atherosclerotic Disease in Patients Undergoing Mechanical Thrombectomy for M1 Occlusion
Authors: Ume Kiddy L , Dandapat Sudeepta , Weber Matthew , Zevallos Cynthia , Levy Abigail , Ortega-Gutierrez Santiago , Siddiqui Fazeel
Published: June 2021

Introduction:
The hyper-dense middle cerebral artery sign (HMCAS) on computed tomography (CT) is associated with ischemic stroke involving the middle cerebral artery (MCA) territory. While its presence is indicative of acute thromboembolic disease, the clinical implications of its absence in patients presenting with M1 occlusions have not been widely studied.

Methods:
We retrospectively analyzed104 consecutive patients presenting with acute M1 occlusions undergoing mechanical thrombectomy. Pertinent clinical/radiological variables were obtained from the electronic medical records and review of angiographic images. Presence of HMCAS was defined as a difference of >5 Hounsfield units (HU) between the occlusion site and the corresponding contralateral MCA segment. Patients were stratified based on the presence (HD group) vs. absence (nHD group) of HMCAS. Primary outcomes included mortality, reperfusion status (TICI), and 3-month Modified Rankin Scale (mRS). Other relevant clinical variables were statistically analyzed and compared. Statistical analyses were two-tailed and considered significant if p<0.05.

Results:
Out of the 104 patients with M1 occlusions, 78 had a measurable HMCAS (HD group), while 22 patients did not (nHD group). 4 patients were excluded due to CT artifacts. Age (69.2 ± 16.0), presenting NIHSS (15.8 ± 5.1), and time to groin (347.0 ± 282.6 min) were similar in the two groups. Mortality and 3-month mRS were 50% and 4.4 (±1.9) in the nHD group versus 27% and 3.1 (±2.2) in the HD group, both significant, with p=0.0201. and p=0.0152, respectively. The nHD patients had significantly higher incidence of diabetes (40.9% vs. 19.2%, p=0.0178). TICI score was unfavorable (2A, 1, or 0) in 31.8% of the nHD- and 24.4% of the HD patients, although not statistically significant. Lesions were presumed to be atherosclerotic (based on cerebral angiography) in 40.9% of nHD- and 7.7% of HD cases (p=0.00006).

Conclusion:
Absent HMCAS - defined as a <5 HU difference between bilateral corresponding MCA segments on initial CT - is associated with poor functional outcome after mechanical thrombectomy in patients presenting with M1 occlusion. There is a significantly higher incidence of atherosclerotic occlusions in this patient population.
Abstract WP63: AI-Augmented Review of CT Brain Exams to Determine Rate of Missed Diagnoses of Intracranial Hemorrhage by Practicing Neuroradiologists
Authors: Chodakiewitz Yosef , Maya Marcel , Pressman Barry
Published: June 2021

Background:
Radiological diagnosis is error prone, yet accurate error rates are difficult to study. Current literature typically relies on manual review of scans, likely placing an upper limit on accuracy. AI-assisted retrospective review of finalized CT scans may help quantify error rates better than conventional methods used in prior discrepancy studies. In this fashion, we focus here on quantifying the rate of intracranial hemorrhage (ICH) missed on neuroradiologist (NR) finalized CT reports.

Evaluation:
A retrospective study compared discrepancies between CT reports and AI-based detection of ICH. All non-contrast CT brain cases were collected from our institution over two months; cases reported as negative for ICH were included (N=1812), while cases reported as suspicious for ICH (N=504) were excluded. Fellowship-trained NRs finalized all reports. An AI-tool trained to detect ICH was then run on the case set. A subset of discrepant “negative by report” but ”positive by AI” cases was isolated (N=36). This subset was then reviewed again by two separate experimenter-NRs and then together as needed to achieve consensus regarding their agreement or disagreement with the AI-based ICH detection. Upon final consensus, 22 cases of ICH detected by AI were missed on finalized reports, yielding an error rate of 4.2% (22/(504+22)).

Discussion:
This ICH miss rate of 4.2% on finalized NR reports was higher than expected, likely reflecting a higher sensitivity involved in AI-assisted screening of scan/report discrepancies in comparison to conventional manual review. Missed ICH can result in potentially devastating consequences for a patient. Better quantification and characterization of ICH diagnostic misses might offer insight into biases that dispose to error, and help guide improved radiologist performance and better patient care.

Conclusion:
AI-augmentation may help flag potential discrepancies between scans and their reports, possibly improving quantification of error rates among practicing radiologists. The result further suggests that AI-augmented ICH detection, if used in real time, may improve radiologist detection of ICH that may otherwise get overlooked.
Abstract WP68: CT Perfusion Collateral Index in Assessment of Collaterals in Patients With Acute Ischemic Stroke: A New Imaging Biomarker
Authors: Nael Kambiz , Larson Jonathan , Sakai Yu , Goldstein Jared , Deutsch Jacob , Awad Ahmed J , Pawha Puneet , Aggarwal Amit , Fifi Johanna , Deleacy Reade , Yaniv Gal , Shoirah Hazem , Mocco J
Published: June 2021

Purpose:
Perfusion collateral index (PCI) has been recently defined as a promising measure of collateral flow. We aim to evaluate the collateral status via CT-based PCI in association with outcome measures such as final infraction volume, recanalization status and functional outcome in patients presenting with acute ischemic stroke (AIS) and in a comparative analysis against CTA and DSA collateral scores.

Methods:
AIS patients with anterior circulation large vessel occlusion who had baseline CTA and CT perfusion and underwent endovascular treatment were included. CTA collateral scores were calculated using modified Tan score and DSA collateral scores were evaluated by ASITN grading. In addition, previously described
PCI
defined as the volume of moderately hypoperfused tissue (ATD
2-6sec
) multiplied by its corresponding rCBV was calculated in each patient. The association of CTA and DSA collateral scores and PCI were assessed against 3 measured outcomes: 1) Final infarction volume obtained from follow up MRI; 2) Final recanalization status defined by TICI scores; 3) Functional outcome measured by 90-day mRS.

Results:
A total of 53 patients met inclusion criteria (27F; mean/SD age: 70.1 ± 13 years; median NIHSS: 14). Final infarction volume (mean/SD: 30/40 mL), excellent recanalization defined by TICI >2C was achieved in 36 (68%) patients, and 23 patients (43%) had good functional outcome (mRS <2). Having good collaterals on all 3 modalities (CTA, DSA, CTP-PCI) were associated with significantly (p<0.05) smaller infarction volume. However only good collaterals determined by CTP-PCI was predictive of achieving excellent recanalization (p=0.001) or good functional outcome (p=0.01) (
Figure 1
).

Conclusion:
Collateral status assessed via CT-PCI outperforms CTA and DSA collateral scores in prediction of excellent recanalization and good functional outcome and may be a promising imaging biomarker of collateral status in patients with AIS.
Abstract WP69: Does CBF Below 30% Actually Represent Infarct Core in Acute Ischemic Stroke? Proof of Mis-Concept
Authors: Rubiera Marta , Garcia-Tornel Alvaro , Ciolli Ludovico , Olive Marta , Tomasello Alejandro , Rodriguez-Luna David , Pagola Jorge , Muchada Marian , Boned Sandra , Deck Matias , Requena Manuel , Molina Carlos A , Ribo Marc
Published: June 2021

On CT perfusion (CTP), cerebral blood flow < 30% than the contralateral hemisphere (CBF<30) is considered a marker of infarct core. Our hypothesis is that CBF<30 defines a reversible poor hemodynamic area rather than core and aimed to study CBF<30 evolution over time, its relationship with leptomeningeal collateral circulation (CC) and outcome parameters.

Methods:
Retrospective analysis of a prospective database of acute ischemic strokes who underwent CTP on admission and immediately after endovascular thrombectomy (EVT). CC was graded on CT angiography (CTA) by the modified Tan scale (good CC: 2-3 grades). Complete recanalization was defined by modified Thrombolysis in Cerebral Ischemia ≥ 2B. Final infarct volume (FIV) was semi-automatically measured on 48-72h CT; ghost core was defined as: admission CBF<30 - FIV > 10cc.

Results:
We included 494 patients; median time from onset to CT: 137 min (IQR 68-238). Median CBF<30 volume on admission: 8 cc (0-28). With longer onset-to-CT times ischemic changes progressively increased on non-contrast CT (ASPECTS decay r=-0.21, p<0.01), however CBF<30 progressively decreased (r=-0.13, p<0.01). 294 patients (60.6%) presented good CC. Good CC was associated with lower admission CBF<30 (median CBF<30 on good CC: 0 cc (0-12) vs 28.5 (7-57) on poor CC, p<0.01). In recanalized patients (419, 84.8%), CBF<30 virtually disappeared in CTP post-EVT (n=103) (median CBF<30: 0ml (IQR 0) (88%= 0 cc) despite that most patients developed established infarcts (median FIV 16 (4-50), 59% FIV>10cc)). Even in recanalized patients, baseline CBF<30 only moderately correlates with FIV (r=0.55, p<0.01). A ghost core was identified in 13.7% (34.5% if CT was performed <90min from onset). 46.6% patients had good functional outcome (mRS<3 at 3 months). A multivariate analysis of recanalized patients showed that CC (OR 0.43, CI 0.27-0.69, p<0.01) but not CBF<30 was an independent predictor of functional outcome.

Conclusion:
CBF<30 represents an hemodynamic state rather than established infarct core, evolving over time inversely as it should physiologically (increase of infarct core over time). CBF<30 should be considered as an outcome predictor but not used as exclusion criterion for EVT, especially in early time-windows.
Abstract WP72: Low kV Computed Tomography Cerebral Angiogram Using Third-Generation Reconstruction Algorithm Provides Significantly Improved Image Quality With Lower Contrast and Radiation Exposure
Authors: Bathla Girish , Priya Sarv , Soni Neetu , Derdeyn Colin
Published: June 2021

Introduction/Aim:
We aimed to determine if CTA imaging using third generation reconstruction algorithm and lower contrast dose-low kVp technique (LD-CTA) was comparable to regular contrast dose CTA at 120 kVp using a sinogram affirmed iterative reconstruction algorithm (ND-CTA).

Methods:
Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Contrast- and signal-to-noise ratios (CNR/ SNR) were compared for the mid-M1-MCA vessels bilaterally and the mid-basilar artery. Fisher’s exact test was used to compare subjective image quality. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values. Finally differences in contrast dose, CT-dose index (CTDI) and dose length product (DLP) were compared using Mann-Whitney U test.

Results:
Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% (84-100%) for group-1 versus 89.2% (82%-98%) for group-2). The subjective scores were not statistically different in the anterior circulation but showed significantly better image quality for the basilar artery. LD-CTA group showed significantly better SNR and CNR (p < 0.0001) for both MCA vessels and the basilar artery. ICC showed moderate correlation (0.51-0.63) between the observers. Student paired t-test did not show any significant difference between the observers. LD-CTA group also used lower contrast (49 cc versus 103 cc in ND-CTA) and had lower radiation exposure (DLP/ CTDI for both groups 268.3/12.42 vs 519.5/ 25.15, both < 0.0001).

Conclusion:
Next-generation reconstruction algorithm and low-Kv scanning significantly improved image quality on cerebral CTA images despite lower contrast dose, and in addition, have lower radiation exposure.
Abstract WP74: Automated Measurement of Cerebral Atrophy and Outcome in Endovascular Thrombectomy
Authors: Diprose William K , Diprose James P , Wang Michael T , Tarr Gregory P , McFetridge Andrew , Barber P. Alan
Published: June 2021

Background and Purpose:
Methods of identifying ischemic stroke patients with a greater probability of poor outcome following endovascular thrombectomy (EVT) might improve shared treatment decision-making between patients, families and physicians. Visually-graded cerebral atrophy is associated with worse functional outcome following EVT. We used an objective, automated method to measure cerebral atrophy and investigated whether this was associated with functional outcome in EVT patients.

Methods:
Consecutive EVT patients from a single-center registry were studied. CT brain scans were segmented with a combination of a validated U-Net and Hounsfield unit thresholding. Intracranial cerebrospinal fluid (CSF) volume was used as a marker of cerebral atrophy and calculated as a proportion of total intracranial volume. The primary outcome was functional independence, defined as a 3-month modified Rankin Scale (mRS) score of 0-2.

Results:
360 EVT patients were included. Functional independence was achieved in 204 (56.7%) patients. The mean±SD CSF volume was 9.0±4.7% of total intracranial volume. Multivariable regression demonstrated that increasing CSF volume was associated with reduced functional independence (OR=0.65 per 5% increase in CSF volume; 95% CI, 0.48- 0.89; P=0.007) and higher 3-month mRS scores (common OR=1.59 per 5% increase in CSF volume; 95% CI, 1.05-2.41; P=0.03).

Conclusions:
Cerebral atrophy determined by automated measurement of intracranial CSF volume is associated with functional outcome in patients undergoing EVT. If validated in future studies, this simple, objective, and automated imaging marker could potentially be incorporated into decision-support tools in order to improve shared treatment decision making.
Abstract WP77: Final Infarct Volume May Predict Functional Outcome After Mild, Nondisabling Ischemic Stroke: Results From the PRISMS Trial
Authors: Prabhakaran Shyam , Vagal Achala , Sucharew Heidi , Tomsick Thomas , Carrozzella Janice , Kendall Jed , Porbandawala Nabeel , Stanton Robert , Broderick Joseph P , Kleindorfer Dawn O , Levine Steven R , Romano Jose , Saver Jeffrey L , Yeatts Sharon , Khatri Pooja
Published: June 2021

Introduction:
In patients with acute cerebral ischemia (ACI) within 3h of onset with mild deficit judged as nondisabling at presentation, up to 20% experience poor functional outcome at 90 days. We tested the hypothesis that the presence of infarction at 24h would independently predict worse outcome at 3 months, and also explored the role of final infarct volume (FIV) on outcomes.

Methods:
The phase 3b, randomized PRISMS trial compared intravenous alteplase to aspirin for mild (NIHSS 0-5), nondisabling stroke at <3 h from onset. In a prespecified analysis, we included patients with 24h MRI performed and excluded acute cerebral ischemia mimics. Central readers assessed Day 24h MRIs for acute infarct, chronic infarcts, and white matter hyperintensity (WMH) burden; FIV and WMH volumes were measured quantitatively using semi-automated software. The primary outcome was 3-month EQ5D scores, a measure of QOL, and the secondary outcome was modified Rankin Scale (mRS) scores, a measure of disability. Multivariable linear regression and proportional odds cumulative logit models were used to evaluate the association between (1) acute infarction presence and (2) FIV on the primary and secondary outcomes, respectively, adjusting for relevant covariates (Table 1).

Results:
Of 313 patients enrolled, 273 had a final diagnosis of ACI and 212/273 (77%) had 24h MRI scans. Acute infarcts were present In 109 (51%), and median FIV was 1.20 mL (IQR 0.57-2.50). No association between presence of acute infarcts and 3-month EQ5D (p=0.84) or mRS (p=0.17) scores was observed (Table 1A). No association between FIV and EQ5D scores (p=0.31) was observed as well, but FIV was strongly associated with mRS scores (OR 1.11, 95% CI 1.04-1.18, p<0.001), in adjusted models (Table 1B).

Conclusions:
Among patients presenting with mild, nondisabling ACI, FIV appears to be associated with worse functional outcome. Since this was a post-hoc analysis, this hypothesis requires further prospective study.
Abstract WP82: Evaluation of Infarct Core Determination in Patients With Large Vessel Occlusion
Authors: Lopez-Rivera Victor , Fan James , Lee Songmi , Kumar Aditya , Inam Mehmet Enes , Yoo Albert J , Savitz Sean I , McCullough Louise , Giancardo Luca , Sheth Sunil A
Published: June 2021

Introduction:
Estimation of infarct core (IC) is a critical component in the evaluation of patients with large vessel occlusion (LVO) for endovascular stroke therapy (EST), but the optimal method to determine IC is uncertain.

Methods:
From our prospectively maintained institutional registry, we identified acute ischemic stroke (AIS) patients with LVO between 1/2018 and 2/2019. Patients were included if they underwent consecutively and technically adequate non-contrast CT, CT angiography (CTA), and CT Perfusion (CTP). ASPECTS was assessed by an experienced neuroradiologist. CTP IC was determined using RAPID. Final infarct volume (FIV) was determined by manual volume segmentation on DWI sequences from 24h MRI, but this analysis was limited to patients who underwent EST with TICI 2b/3 reperfusion within 120 minutes of presentation CT imaging, to minimize IC growth affecting the results. Correlation between IC measurements was calculated using Spearman p. Results are provided as median [IQR].

Results:
Among 772 patients with LVO, 199 patients met inclusion criteria. Median age was 69 [59-79], 47% were female and 57% were white. Median NIHSS was 15 [9-21], the most common occlusion site was M1 MCA (55%). Median CT ASPECTS was 7 [6-9], median CTA ASPECTS was 6 [5-7], and median CTP-RAPID IC volume was 11 [0-47]. Presentation CT ASPECTS correlated with CTP-RAPID IC (Fig. 1A, r=-0.57; p<0.0001), as did CTA ASPECTS (Fig. 1B, r=-0.61; p<0.0001). Presentation CTA ASPECTS correlated with CTP-RAPID IC in patients presenting 0-6 hrs (CTA r=-0.69; p<0.0001) and 6-24 hrs (r=-0.58; p<0.0001). Among 90 patients with EST and TICI 2b/3, presentation CTA ASPECTS correlated better with FIV (r=-0.65; p<0.0001) compared to presentation CTP-RAPID (r=0.61; p<0.0001).

Conclusions:
In patients with LVO in the anterior circulation, CTA ASPECTS correlated well with CTP-RAPID IC in the early and late time windows, and was more reflective of 24h MRI findings in patients who received EST.
Abstract WP85: Clinical and Imaging Predictors, and Functional Outcomes, of Fast, Intermediate, and Slow Progression Among Patients With Large Vessel Occlusion Acute Ischemic Stroke
Authors: Seo Woo-Keun , Liebeskind David S , Yoo Bryan , Sharma Latisha , Jahan Reza , Duckwiler Gary , Tateshima Satoshi , Nour May , Szeder Viktor , Colby Geoffrey , Starkman Sidney , Rao Neal , Bahr Hosseini Mersedeh , Saver Jeffrey L
Published: June 2021

Background:
Speed of infarct progression varies widely in acute ischemic stroke and is a major determinant of outcome. Patient demographic, clinical, and imaging features associated with slow, intermediate, and rapid infarct growth have not been well delineated.

Methods:
In a prospectively maintained stroke center registry, we analyzed consecutive patients with anterior circulation large vessel occlusion who underwent first multimodal MRI or CT imaging within 24 hours of onset. The speed of initial infarct progression was calculated as ischemic core volume at first imaging divided by the time from stroke onset to imaging.

Results:
Among the 88 patients, age was mean 71.6 ± 15.0; 51% were women; initial NIHSS was 16.1 ± 6.5), and time from onset to first imaging was median 3.3h (full range 0.6 - 23.0). The speed of infarct progression was median 2.2 cc/hr (interquartile range 0 - 8.7), ranging most widely among patients imaged within the first 6 hours after onset. Faster speed of infarct progression was positively independently associated with low collateral score (OR 3.30, 95%CI 1.25 - 10.49) and arrival by emergency medical services rather than transfer (OR 3.34, 95% CI 1.06 - 10.49) and negatively independently associated with prior ischemic stroke (OR 0.12, 95%CI 0.03 - 0.50) and coronary artery disease (OR 0.32, 95%CI 0.10 - 1.00). Among the 67 patients who underwent endovascular thrombectomy, slower speeds of infarct progression were associated with shift to reduced levels of disability at discharge (OR 3.26, 95% CI 1.02 - 10.45). In addition, slower speed of infarct progression was associated with favorable shift to recanalization by thrombectomy (OR 8.30, 95%CI 0.97 - 70-.87) and reduced radiologic hemorrhagic transformation (OR 0.34, 95% CI 0.12 - 0.94).

Conclusion:
Slower speed of initial infarct progression is associated with high collateral score, prior ischemic stroke, and coronary artery disease, supporting roles for both collateral robustness and ischemic precondition in fostering tissue resilience to ischemia. Among patients undergoing endovascular thrombectomy, speed of initial infarct progression is a major determinant of clinical outcome.
Abstract WP86: MRI-Guided Mismatch Imaging to Identify Patients for Thrombolysis in the Unknown Time Window: Insights From the WAKE-UP Trial
Authors: Scheldeman Lauranne , Wouters Anke , Christensen Soren , Dupont Patrick , Cheng Bastian , Ebinger Martin , Endres Matthias , Fiebach Jochen B , Gerloff Christian , Muir Keith W , Nighoghossian Norbert , Pedraza Salvador , Simonsen Claus Z , Boutitie Florent , Thijs Vincent , Thomalla Götz , Lemmens Robin
Published: June 2021

Background:
Two imaging paradigms, the diffusion-weighted imaging (DWI) - fluid attenuated inversion recovery (FLAIR) and perfusion-weighted imaging (PWI) - DWI mismatch, used in the Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke (WAKE-UP) and Extending the Time for Thrombolysis in Emergency Neurological Deficits (EXTEND) trial respectively, can identify patients eligible for thrombolysis if stroke onset time is unknown.

Objectives:
We explored presence and influence of the PWI-DWI mismatch on outcome in WAKE-UP.

Methods:
We included patients screened for DWI-FLAIR mismatch in WAKE-UP who also underwent PWI. We defined PWI-DWI mismatch according to EXTEND as core <70 ml, mismatch ratio >1.2 and mismatch volume >10 ml. Primary efficacy end point was favorable outcome defined as modified Rankin Scale score of 0-1, adjusted for age and symptom severity.

Results:
The analysis included 343 screened patients of which 162 were randomized and treated. Of 343 screened patients, 162 had a DWI-FLAIR mismatch, 80 had a PWI-DWI mismatch and of those, 36 had both mismatches. Proportions of PWI-DWI mismatch did not differ in those with (22%, 36/162) vs without (24%, 44/181) DWI-FLAIR mismatch (p=0.74). PWI-DWI mismatch status did not modify treatment effect of thrombolysis (p for interaction=.68). In patients with both DWI-FLAIR and PWI-DWI mismatch, favorable outcome was present in 52% of those treated with alteplase (11/21) vs 38% (5/13) in those receiving placebo (adjusted OR 2.02; 95% CI 0.44-9.24, p=0.36). Selection based on the presence of the DWI-FLAIR mismatch identified more thrombolysis eligible patients (47%; 95% CI 42%-53%) compared to the PWI-DWI mismatch (23%; 95% CI 19%-28%, p<.0001). Screening for either one of the mismatch profiles resulted in a yield of 60% (95% CI 55%-65%) candidates for thrombolysis.

Conclusion:
We did not identify an association between the DWI-FLAIR and PWI-DWI mismatch. PWI-DWI mismatch status did not modify treatment effect in patients with DWI-FLAIR mismatch, but the analysis was underpowered. Screening for the presence of either one of the mismatch profiles with MRI seems the most inclusive approach to identify patients who can still benefit from thrombolysis in the unknown time window after stroke onset.