bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P308: Machine Learning Based Models of the 30-Day Readmission for Stroke Patients Using Electronic Health Record Data
Authors: Darabi Negar , Hosseinichimeh Niyousha , Noto Anthony , Zand Ramin , Abedi Vida
Published: March 2021

Background:
At a personalized level, identification of patients at higher risk of 30-day readmission and in need of special clinical attention could lower their chances of readmission. While at a system’s level, reducing hospital readmission improves the overall quality of care delivery and reduces the associated cost burden.

Objective:
To enhance understanding of the predictors of 30-day readmission after ischemic stroke and identify high-risk individuals. We aimed to compare the performance and the predictive power of machine learning-based methods and identify the best model.

Method:
The electronic health records (EHR) of acute ischemic stroke patients were extracted from two tertiary centers within the Geisinger Health System between January 1, 2015, and October 7, 2018. A total of 61 variables, including clinical variables, demographical characteristics, discharge status, and type of health insurance were used in this study. Patients were randomly split for model development (80%) and testing (20%). Random forest, gradient boosting machine, extreme gradient boosting (XGBoost), support vector machine, and logistic regression, were developed to predict the 30-day readmission after stroke. The models were evaluated based on the area under the curve (AUC), sensitivity, specificity, and positive predictive value (PPV).

Results:
A total of 3,184 patients with ischemic stroke (mean age: 71±13.90 years, men: 51.06%) were included in this study. From the 3,184, 301 (9.40%) were readmitted within 30-day. The best performance was obtained when XGBoost was used with ROSE-sampling. The AUC for the test set was 0.74 (95% CI: 0.64-0.78) with PPV of 0.43. The top four predictors of the 30-day readmission model were National Institutes of Health Stroke Scale score above 24, insert an indwelling urinary catheter, hypercoagulable state, and percutaneous gastrostomy.

Conclusions:
Machine learning model can be designed to predict 30-day readmission after stroke using structured data from EHR. Among the five algorithms analyzed, XGBoost had the best performance.
Abstract P315: Radiomics Signature of DWI-FLAIR Mismatch Correlates With Clinical Phenotype of Patients With Large Vessel Occlusion Stroke
Authors: Regenhardt Robert W , Bretzner Martin , Bonkhoff Anna K , Zanon Zotin Maria Clara , Etherton Mark R , Das Alvin S , Alotaibi Naif M , Vranic Justin E , Kuchcinski Gregory , Stapleton Christopher J , Patel Aman B , Leslie-Mazwi Thabele M , Rost Natalia S
Published: March 2021

Introduction:
For patients presenting with large vessel occlusion for endovascular thrombectomy (EVT), FLAIR hyperintensity within ischemic lesions may be inversely related to parenchymal viability but relies on subjective grading. Radiomics is an emerging image quantification methodology that may more objectively represent continuous image characteristics. We propose a novel radiomics approach to describe infarct FLAIR positivity and evaluate its correlation with clinical presentation.

Methods:
For patients with pre-EVT MRI, ischemic lesions were manually segmented on DWI, co-registered to FLAIR and visually graded for FLAIR positivity (0, +, ++). Radiomics were extracted within the ischemic lesion outlines on FLAIR. LASSO regression was used to select features for the DWI-FLAIR mismatch radiomics signature. Canonical correlation analysis was used to relate this signature to clinical features.

Results:
We identified 103 patients with mean age 68±16 years and 63% female. The radiomics signature of DWI-FLAIR mismatch included FLAIR histogram kurtosis and gray level cluster shade; both correlated with visual grading (
Figure 1A
). The first of the estimated 3 canonical pairs was statistically significant (canonical correlation=0.50, corrected p=0.009); kurtosis was positively associated with atrial fibrillation and age, while negatively associated with last known well, smoking, and diabetes (
Figure 1B
).

Conclusion:
The radiomics signature of DWI-FLAIR mismatch before EVT correlates with visual grading and may provide a continuous metric to describe infarct evolution. Further exploration of larger datasets is required to determine additional granular relationships with clinical features.
Abstract P32: Advanced Practice Provider-Based Acute Stroke Protocol Performs Well Compared to a Resident-Based Protocol
Authors: Grose Noah , Forrest Cassandra , Heaton Sharon , Lee Vivien
Published: March 2021

Introduction:
The administration of intravenous tissue plasminogen activator (IVtPA) for acute ischemic stroke (AIS) is typically done by neurology resident physicians at academic stroke centers. We sought to compare the performance of an advanced practice provider (APP)-based IVtPA protocol to a resident-based protocol.

Methods:
We performed a retrospective review of Emergency Room (ER) acute stroke codes from January 1, 2018 to January 1, 2019 that received AIS reperfusion therapy, including IVtPA or mechanical thrombectomy (MT). Inpatient AIS were excluded. During this timeframe, 5 acute stroke-trained nurse practitioners covered the daytime shifts for acute stroke codes on a rotating basis (during the hours of 7:00 am -4:00 pm, Monday through Friday). The neurology residents continued to cover all other stroke code shifts. We collected data on baseline demographics, initial National Institutes of Health Stroke Scale (NIHSS), door to needle (DTN) time, and door to groin puncture (DTG) time. Statistical analyses were performed using JMP software package (version 14). All tests were 2-sided, and a
P
value was considered significant at <0.05.

Results:
Among 322 AIS case who received acute reperfusion therapy, 133 (41.4%) received IVtPA, 200 (62.3%) received MT, and 11 (3.4%) received both. Among the 133 IVtPA patients, there was no difference in age (62.2 vs 59.9, p 0.56) or mean initial NIHSS (7.7 vs 8.2, p 0.75) when comparing the APP-based protocol to the resident-based protocol group, but patients seen by the APP were more likely to be male (78.3 vs 42.7%, p 0.0015). Compared to the resident-based protocol, the APP-based protocol had faster mean DTN times (38.9 vs 54.7 minutes, p 0.0374) and were more likely to have final diagnosis of stroke (95.7% vs 70%, p 0.0034). Among the 200 MT patients, the DTG time showed a trend for faster times for the APP-based protocol, although this was not significant (60.5 vs 76.5, p 0.0083).

Conclusion:
At our academic comprehensive stroke center, APP driven acute stroke code protocols perform as well as resident-based protocols in terms of time to reperfusion therapy.
Abstract P320: Impact of Inpatient TEE on Secondary Stroke Prevention
Authors: Miller Elan , Herpich Franziska , Gruder Olivia , Patel Priyadarshee
Published: March 2021

Introduction:
Transthoracic echocardiogram (TTE) is part of the standard stroke workup. If stroke remains cryptogenic after TTE and rest of the initial stroke evaluation, a transesophageal echocardiogram (TEE) is often performed. Evidence about when and in whom TEE should be done is lacking and reported effect on management vary widely. Our goal was to investigate the impact of TEE on stroke management.

Methods:
We performed a retrospective study of patients admitted with acute ischemic stroke (AIS) between April 2017 and December 2019 to a single, tertiary care, academic center. All patients received TTE and TEE while inpatient. Demographic data, clinical characteristics, results of echocardiograms and discharge medications were collected via chart review. Primary endpoint was change in stroke management based on TEE results. Secondary endpoint discovery of potential stroke etiology and factors associated with TEE results leading to change in management including age, multi-territory infarcts, TTE and vascular risk factors. We used Fisher’s Exact test and 2-sided Wilcoxon-Mann-Whitney rank-sum test.

Results:
We analyzed 92 patients with AIS who received both TTE and TEE. Median age was 56 (range 23-88), 51% were male and median NIHSS on admission was 9 (0-30). Middle cerebral artery infarct occurred in 58% and 32% had infarcts in multiple territories. Median hospital stay was 9 days (2-43). TEE revealed findings not seen on TTE in 52% and changed management in 16.3% of cases. Surprisingly, It appeared that older age was more likely to be associated with change of management based of TEE results (median age 61 vs. 55), as were multi-territory infarcts (46.7% vs 28.6%). However, neither of these results were statistically significant. Normal TTE findings were similar in both groups (60.0% vs 57.1%) and no vascular risk factors were associated with change of management based on TEE.

Conclusion:
TEE changes secondary stroke management in approximately one-sixth of patients and revealed new findings in about half. A larger study is needed to find factors associated with change in management based on TEE results.
Abstract P322: Time Course and Clinical Correlates of Retinal Diffusion Restrictions in Acute Central Retinal Artery Occlusion: Findings From a Retrospective Cohort Study
Authors: Danyel Leon Alexander , Connolly Florian , Siebert Eberhard
Published: March 2021

Background:
To systematically evaluate retinal diffusion restrictions (RDR) in patients with central retinal artery occlusion (CRAO) using a standard stroke DWI-EPI sequence.

Methods:
CRAO patients admitted between 01/2010 to 12/2019 and MRI performed within 2 weeks of clinical onset were included in this retrospective cohort study. Evaluation of diffusion-weighted imaging for retinal diffusion restrictions was performed by a neuroradiologist blinded for CRAO side and clinical data. The influence of selected clinical and technical MRI parameters on the presence of RDR in CRAO was assessed using Chi-squared statistics and Bonferroni post-hoc analysis.

Results:
127 patients (69,6 ± 13,9 years; 59 female) with 131 DWI scans were included in the study. Overall sensitivity of RDR in CRAO was 67,2%. RDR were falsely attributed to the wrong eye in a single case only (0,8%). RDR in CRAO were reliably identified up to 1 week after onset of amaurosis with highest sensitivity in DWI performed within 24 hours (79%). Contrariwise, detection rates of RDR dropped significantly in the second week (10,0%; p=0,0006). Absence of RDR was more prevalent in patients without fundoscopic presence of retinal edema (60% vs. 27,1%; p = 0,004) and in subjects with restitution of visual acuity at discharge (75% vs. 28,4%; p = 0,006).

Conclusions:
RDR in CRAO can reliably be identified in a majority of CRAO patients with standard stroke DWI performed within 24 hours to 1 week after onset of amaurosis. Further studies are needed to investigate the potential of stroke DWI in hyperacute CRAO and the utility of RDR in selecting patients for thrombolytic therapy.
Abstract P325: Validation of Deep Learning Based Critical Hypoperfusion and Ischemic Core Prediction in a Multicenter External Randomized Controlled Trial
Authors: Yu Yannan , Xie Yuan , Christensen Soren , Gong Enhao , Lansberg Maarten G , Albers Greg , Zaharchuk Greg
Published: March 2021

Objective:
We previously developed two separate deep learning (DL) models to segment the ischemic core and critically hypoperfused tissue on baseline imaging of acute ischemic stroke patients. We aimed to validate the models in an external, multi-center randomized clinical trial (DEFUSE3) and compare with the current clinical standard.

Methods:
The DL models were previously trained in a separate dataset in which follow-up MRI, obtained at 3-7 days, was used as the reference for critically hypoperfused tissue in patients who did not reperfuse and as the reference for the ischemic core in patients who did reperfuse. For validation, we included DEFUSE3 patients with adequate quality baseline MR perfusion and a 24-hour follow-up DWI scan. The 24-hour DWI lesion served as the reference for ischemic core in patients in the thrombectomy arm and for critically hypoperfused tissue for patients in the medical arm. RAPID was used to generate perfusion maps (Tmax, cerebral blood flow, cerebral blood volume, and mean transient time). The accuracy of segmenting the ischemic core and critically hypoperfused tissue on baseline imaging was compared between the DL approach and the traditional thresholding approach implemented in RAPID.

Results:
In the 46 patients included for analysis, 24 were in the medical arm and 22 in the thrombectomy arm. Compared to a traditional thresholding method, the DL model segmented the ischemic core more accurately (AUC of 0.92 vs 0.72, p=0.0001 and volume difference of -8ml vs -21ml, p=0.001). Similarly, the DL model segmented critically hypoperfused tissue more accurately (AUC of 0.93 vs 0.80, p<0.0001; volume difference 14ml vs. 55ml, p=0.0005). However, great heterogeneity in final infarct was noticed in medical arm. See tables and figures.

Conclusions:
The DL-based critical hypoperfusion and ischemic core prediction provides more accurate prediction on final infarct than a commonly used thresholding method in this external validation.
Abstract P328: Transcranial Doppler as a Cost-Effective, Safe Screening Tool in Embolic Stroke of Undetermined Source
Authors: Patrick Lauren , Wang Zi , Cross Danielle B , Meisel Karl M
Published: March 2021

The diagnostic evaluation of embolic stroke of undetermined source (ESUS) requires investigation of paradoxical embolism via shunts. ESUS evaluation involves a transthoracic echocardiogram (TTE) with saline contrast study, then a transesophageal echocardiogram (TEE) for further evaluation of a patent foramen ovale (PFO), as TTE lacks sensitivity. PFO closure is offered for significant shunts. TEE is the gold standard but transcranial doppler (TCD) may help in the ESUS algorithm for shunts. TCD reduces procedural and anesthetic risk to patients, may be cost-effective, and mitigates risk to providers during the COVID-19 pandemic (1-2). Studies have shown the accuracy of TCD with microbubble for the diagnosis of shunts compared to TEE; a recent meta-analysis found weighted average sensitivity and specificity of 97% and 93%, respectively (3). We propose introducing TCD into the algorithm to evaluate ESUS as a screening tool with similar fidelity to TEE. According to our algorithm, patients under the age of 60 years with ESUS will undergo TTE with microbubble, then those at low risk of valvular disease or cardiac structural pathology will undergo TCD-emboli protocol. Patients with grade 0-2 shunts will receive medical therapy, while shunt grades 3-5 will be referred for intraoperative TEE and closure. We reviewed records of a TCD-emboli protocol followed by TEE from 2014-2020 to ensure similar validity to published data. The sensitivity and specificity of shunt detection amongst 34 patients with ESUS was 94.7% (CI 73.9% - 99.9%) and 93.3% (68.1%-99.8%), respectively. Cost-benefit analysis of patients who received TCD prior to TEE was calculated as the average cost difference. We calculated a conservative estimate of $2741-$3649 in cost reduction per patient, excluding the cost of TEE anesthesia. In conclusion, TCD-emboli protocol is a cost-effective and safe screening tool with high accuracy in comparison to TEE in the diagnostic evaluation of ESUS.
Abstract P33: Blind Exchange With the Mini-Pinning Technique Using Tron Fx Retriever for M2 Occlusion Thrombectomy
Authors: Yoshimoto Takeshi
Published: March 2021

Introduction:
Technical improvement to enhance M2 occlusion thrombectomy is desirable. Tron FX® is the only stent-retriever that can be deployed through 0.0165-inch microcatheters. Here we report outcomes of blind exchange with mini-pinning (BEMP) technique using Tron stent-retrievers.

Methods:
Consecutive stroke patients with M2 occlusion treated with 2 x15 mm or 4 x 20 mm Tron stent-retrievers using the BEMP technique were included. The technique involves the deployment of a Tron stent-retriever through a 0.0165-inch microcatheter followed by microcatheter removal and blind navigation of a 3/4MAX aspiration catheter over the bare Tron delivery wire until the aspiration catheter reaches the clot,. Tron stent-retriever was inserted into aspiration catheter like corkscrew, and subsequently pulled as a unit. A first pass effect (FPE), modified FPE (mFPE) and modified Rankin Scale (mRS) score at 90 days were assessed as outcomes.

Results:
Fifteen M2 vessels were treated in 13 patients (5 women, median 81 years of age, and median National Institutes of Health Stroke Scale score 18 [11–25]). BEMP technique was successful in all cases. Whether to use 3MAX or 4MAX was determined according to the target vessel size while proceeding with the procedure (3MAX, n=8; 4MAX, n=5). Final mTICI 2b–3 was achieved in 92% (12/13). FPE and mFPE rates were 50% and 64%, respectively. Six patients (46%) were achieved in mRS score 0–2 at 3 months.

Conclusions:
Tron stent-retriever was successfully and safely used in the BEMP technique for M2 occlusion
Abstract P336: Assistance From Automated ASPECTS Software Improves Reader Performance
Authors: Delio Philip R , Wong Matthew L , Tsai Jenny P , Hinson H. E , McMenamy John , Le Thang , Prabhu Divya , Mann Barry , Copeland Karen , Kwok Keith , Haerian Hafez , Lansberg Maarten G , Heit Jeremy
Published: March 2021

Purpose:
To compare physicians’ ability to read Alberta Stroke Program Early CT Score (ASPECTS) in patients with a large vessel occlusion within 6 hours of symptom onset when assisted by a machine learning-based automatic software tool, RAPID ASPECTS, compared with their unassisted score.

Materials and Methods:
50 baseline CT scans selected from two prior studies (CRISP and GAMES-RP) were read by 3 experienced neuroradiologists who were provided access to a follow-up MRI. The average ASPECT score of these reads was used as the reference standard. Two additional neuroradiologists and 6 non-neuroradiologist readers then read the scans both with and without assistance from the RAPID ASPECTS software and reader improvement was determined. The primary hypothesis was that the agreement between typical readers and the consensus of 3 expert neuroradiologists would be improved with RAPID-assisted vs. unassisted reads. Agreement was based on the percentage of the individual ASPECT regions (50 cases, 10 regions each; N=500) where agreement was achieved.

Results:
Typical non-neuroradiologist readers agreed with the expert consensus read in 72% of the 500 ASPECTS regions, evaluated without software assistance. The automated software alone agreed in 77%. When the typical readers read the scan in conjunction with the software, agreement improved to 78% (P<0.0001, test of proportions). RAPID ASPECTS alone achieved correlations for total ASPECT scores that were similar to the expert readers who had access to the follow-up MRI scan to help enhance the quality of their reads.

Conclusion:
Typical readers had statistically significant improvement in their scoring of scans when the scan was read in conjunction with the automated RAPID ASPECTS software, achieving agreement rates that were comparable to neuroradiologists.
Abstract P340: Chronic Cerebrovascular Damage and Acute Embolic Mechanisms Associated With Acute Leptomeningeal Collateral Flow in Embolic Large Vessel Occlusion
Authors: Hashimoto Tetsuya , Kunieda Takenobu , Honda Tristan , Scalzo Fabien , Sharma Latisha K , Hinman Jason D , Rao Neal M , Nour May , Bahr Hosseini Mersedeh , Saver Jeffrey L , Raychev Radoslav I , Liebeskind David S
Published: March 2021

Background and Purpose:
Acute leptomeningeal collateral flow is vital to maintain blood perfusion to penumbral tissue in acute ischemic stroke due to large vessel occlusion (LVO). However, the degree of this collateral flow differs among patients. Patient premorbid factors as well as factors caused by the mechanisms of stroke are expected to be associated with this collateral flow. We aimed to investigate the clinical determinants of acute leptomeningeal collateral flow in embolic LVO.

Methods:
Among consecutive stroke patients caused by acute embolic anterior circulation LVO, we retrospectively reviewed 108 patients who underwent evaluation of acute leptomeningeal collateral status (CS) on pretreatment CTA admitted from January 2015 to December 2019. Both premorbid information including cerebrovascular risk factors and leukoaraiosis evaluated by the total white matter (WM) Fazekas score on MRI, which was calculated as periventricular plus deep WM scores, and stroke related information including stroke subtypes, severity, time course, and occlusive thrombus characteristics were collected. Among thrombus characteristics, thrombus length was measured by tracing the filling defect of contrast on CTA. The clinical determinants of good leptomeningeal CS (> 50% collateral filling of the occluded territory) were analyzed.

Results:
CS was good in 67 patients (62%). On multivariate logistic regression analysis, cardioembolic stroke subtype was negatively related (OR, 0.170; 95% CI, 0.022-0.868), and mild leukoaraiosis (total WM Fazekas scores of 0-2) was positively related (OR, 9.57; 95% CI, 2.49-47.75) to good CS. On subgroup analysis limited to 82 patients with cardioembolic stroke, shorter thrombus length (OR, 0.913 per mm increase; 95% CI, 0.819-0.999) as well as mild leukoaraiosis (OR, 5.79; 95% CI, 1.40-29.61) were independently related to good CS.

Conclusions:
Premorbid leukoaraiosis and cardioembolic etiology are determinants of acute leptomeningeal collateral flow in embolic LVO. In addition, thrombus length is also a determinant of collateral flow in cardioembolic LVO. These findings indicate that a combination of chronic cerebrovascular damage and acute embolic mechanisms could determine the degree of leptomeningeal collateral flow.
Abstract P342: Histopathological Correlates of MRI-Visible Perivascular Spaces in Cerebral Amyloid Angiopathy
Authors: Perosa Valentina , Munting Leon P , Freeze Whitney , Scherlek Ashley A , Viswanathan Anand , Greenberg Steven M , Van Veluw Susanne
Published: March 2021

Perivascular spaces (PVS) are fluid-filled spaces surrounding cerebral blood vessels. MRI-visible, supposedly enlarged, PVS in the centrum semiovale (CSO) have been associated with cerebral amyloid angiopathy (CAA). PVS enlargement may be due to perivascular clearance impairments, potentially caused by increased amyloid-β (Aβ) accumulation in the walls of vessels in the overlying cortex. We test this hypothesis, using MRI-guided histopathological examination of PVS in CAA autopsy cases. The cohort included 19 CAA (74.1±8.2y, 7F) and 5 non-CAA control cases (88.0±4.9y, 3F). Formalin-fixed hemispheres were scanned on a 3T MRI scanner, including a 500μm T2-weighted sequence. PVS enlargement was assessed in the CSO on in vivo and ex vivo MRI. In addition, local score of PVS enlargement was assessed in four pre-defined juxtacortical areas (Fig.A), using a semiquantitative score and on the corresponding histological sections (Fig.B). Severity of leptomeningeal and cortical CAA were assessed on adjacent Aβ-stained sections, using a semiquantitative scale.PVS enlargement was more severe in CAA cases compared to controls, both on in vivo and ex vivo MRI (p<0.05). PVS enlargement on ex vivo MRI positively correlated with the severity of PVS enlargement on the corresponding histopathological samples (Fig.C). Within CAA cases, the degree of PVS enlargement on ex vivo MRI was positively associated with leptomeningeal CAA severity (n=52 samples, ρ=0.35, p=0.011), but not cortical CAA severity (n=52 samples, ρ=0.10, p=0.472). These preliminary findings confirm that the degree of MRI-visible PVS in juxtacortical brain areas reflects enlargement on histopathology. Moreover, they suggest that PVS enlargement in cases with CAA corresponds to increased CAA severity in the overlying leptomeningeal vessels, possibly as a result of impaired perivascular clearance. Future directions include characterization of individual blood vessels associated with PVS enlargement.
Abstract P346: Segmentation of Chronic Subdural Hematomas Using 3D Convolutional Neural Networks
Authors: Kellogg Ryan T , Levitt Michael , Barros Guilherme , Sen Rajeev , Bass David , Mason James , Vargas Jan
Published: March 2021

Objective:
Chronic subdural hematomas (cSDH) are an increasingly prevalent neurological disease that often requires surgical intervention to alleviate compression of the brain. Management of cSDHs relies heavily upon computed tomography (CT) imaging, and serial imaging is frequently obtained to help direct management. The volume of hematoma provides critical information in guiding therapy and evaluating new methods of management. We set out to develop an automated program to compute the volume of hematoma on CT scans for both preoperative and postoperative images.

Methods:
A total of 128 CT scans (21,710 images) were manually segmented and used to train a convolutional neural network to automatically segment chronic subdural hematomas. We included both preoperative and postoperative coronal head CTs from patients undergoing surgical management of cSDHs.

Results:
Our best model achieved a Dice score of 0.8351 on the testing dataset and an average Dice score of 0.806 +/- 0.06 on the validation set. This model was trained on the full data set with reduced volumes, a network depth of 4, and post activation residual blocks within the context modules of the encoder pathway. Patch trained models did not perform as well and decreasing the network depth from 5 to 4 did not appear to significantly improve performance.

Conclusions:
We successfully trained a convolutional neural network on a dataset of pre and postoperative head CTs containing cSDH. This tool could assist with automated, accurate measurements for evaluating treatment efficacy.
Abstract P347: Thrombus Age and Volume as Predictors of Recanalization and Functional Outcome in Patients With Cerebral Venous Thrombosis
Authors: Manrique Diana M , Barboza Miguel , Alvarado Bolaños Alonso , Cano Nigenda Vanessa , Castellanos Pedroza Enrique , Toledo Treviño Roberto , Calderón García Miguel , Menéndez-Manjarrez María Fernanda , Arauz Antonio
Published: March 2021

Background:
Cerebral Venous Thrombosis (CVT) is an infrequent type of cerebrovascular disease with variable functional outcomes. Different studies have been carried out to identify such predicting factors. Few studies have focused on imaging findings as predictive factors for recanalization and functional outcome after CVT. We analyzed the association of clot burden with image and functional outcomes in CVT.

Methods:
This is a retrospective, cross-sectional study of patients with diagnosis of CVT conducted from November 2003 to august 2019. Imaging data was obtained from PACS system and processed with ITK-SNAP1 program for 3D volumetric measurement of the thrombus; through analysis of T1, T2 and SWI sequences the age of the thrombus was determined. Functional outcome was evaluated using the modified Rankin Scale (mRS) at discharge and 3 months after index event. In order to assess the reproducibility of the thrombus measurement method, a second investigator was assigned to perform similar measurements in 10 patients selected randomly. The age and volume of the thrombus to predict recanalization was evaluated through ROC analysis.

Results:
Twenty-nine patients were studied of which 79.3% were women (n = 23), mean age was 37.79 ± 13.8 years; the superior longitudinal sinus (SLS) was the main sinus affected 44.8% (n = 13) and 44.7% (n = 13) had direct signs on CT study. Mean thrombus volume was 5,463 mm3 ± 6,501 mm3. Regarding the age of the thrombus 72.4% (n = 21) was qualified as acute thrombus with a mean time of 7.21 ± 8.1 days. Age of thrombus demonstrated statistical association with venous sinus recanalization (p = 0.033). Age and volume of the thrombus did not reach statistical significance for functional outcome. The optimal cut-off for the age of the thrombus for complete sinus recanalization in patients with CVT was 4.5 days (Sensitivity of 60% and Specificity of 30%).

Conclusion:
This is a pilot study that evaluated CVT imaging factors for sinus recanalization and functional outcome. Although volume of the thrombus did not predict recanalization, parenchymal lesions or functional outcome in patients with CVT, acute thrombus age could serve as a predictive factor for venous sinus recanalization which is related to functional outcome in these patients.
Abstract P358: Association of Kidney Function and Cerebral Arterial Stiffness
Authors: Lee Eung-Joon , Jeong Hae Bong , Nam Ki-woong , Jeon Kipyoung , Bae Jeonghoon , Jung Keun-hwa , Yoon Byung-woo W
Published: March 2021

Background and Purpose:
Chronic kidney disease (CKD) is known to have affected the systemic vasculature and its remodeling, which eventually led to the systemic arterial stiffness. However, the relationship between cerebral circulation and impaired renal function is poorly understood. To evaluate the effect of renal dysfunction to increase systemic and intracranial arterial stiffness, we assessed the relation between renal resistive index (RRI) and pulsatility index (PI) of the middle cerebral artery (MCA).

Methods:
We included patients with acute lacunar infarction. Demographic and clinical data were collected by retrospective chart review. Bilateral transcranial Doppler ultrasound (TCD) examination of the MCAs was performed using the ST3 Ultrasound system (Spencer Technologies) and PI were calculated. RRI was obtained through kidney Doppler sonography. Subjects with occlusion or significant stenosis of MCA, atrial fibrillation, bilaterally absent transtemporal sonographic windows were excluded.

Results:
Of the 283 included subjects (mean age 67.8 ± 10.2), 74 patients had renal dysfunction (glomerular filtration rate < 60ml/min/1.73m2 at admission) and 49 patients underwent kidney Doppler ultrasound within 1 year since their acute stroke. Renal dysfunction was significantly associated with higher arterial stiffness (median PI 1.12, IQR 0.85 to 1.57 vs. controls PI 0.84, IQR 0.54 to 1.22 [p<0.0001]). There was a proportional relationship between the degree of renal dysfunction and the distal vascular resistance. In multivariate adjusted regression analysis, renal function was related to high PI (p<0.001). Furthermore, there is strong correlation between RRI and PI (
r
=0.65,
p
<0.001).

Conclusions:
In patients with lacunar infarction, renal impairment is an independent determinant of increased arterial stiffness in cerebral circulations. In addition, PI is significantly associated with RRI.
Abstract P366: High Burden of Tract-Specific White Matter Hyperintensities Relates to Impaired Microstructural Integrity of Distal White Matter Tracts in Community-Dwelling Elders
Authors: LIU YANPENG , XIA YIWEI , WANG XIAOXIAO , WANG YI , YANG LUMENG , WANG YIQING , YING YUNQING , LIANG XIAONIU , ZHAO QIANHUA , WU JIANJUN , LIANG ZONGHUI , DING DING , DONG QIANG , QIU BENSHENG , CHENG XIN , GAO JIAHONG
Published: March 2021

Background and purpose:
White matter hyperintensities (WMH) are common in elderly individuals and contribute to age-related cognitive dysfunction. Converging evidence indicates that WMH affect white matter (WM) microstructural integrity in WMH and their penumbra. We aimed to investigate whether this effect extends to the distal WM tracts, and to examine the association between distal WM microstructural integrity and cognitive dysfunction in community-dwelling elderly people.

Methods:
Brain MRI data including FLAIR and DTI sequences of 174 participants (74 ± 5 years) of the Shanghai Aging Study (SAS) were collected and analyzed. For each participant, WMH lesions were segmented automatically. Eighteen major WM tracts were reconstructed using automated quantitative tractography, and the mean diffusivity (MD) of distal WM tracts (excluding an area of 12 mm around the WMH) was calculated. Multivariable linear regression was performed.

Results:
A high burden of tract-specific WMH was related to a high MD of distal WM tracts in the forceps major (FMA), anterior thalamic radiations (ATR), cingulum cingulate gyrus (CCG), corticospinal tract (CST), superior longitudinal fasciculus-parietal (SLFP), superior longitudinal fasciculus-temporal (SLFT), and uncinate fasciculus (UNC). Furthermore, a high MD of distal tracts was linked to worse attention and executive function in the forceps minor (FMI), right CCG, left inferior longitudinal fasciculus (ILF), SLFP, SLFT and UNC.

Conclusions:
The effect of WMH on the microstructural integrity of WM tracts may propagate along tracts to distal regions farther than the penumbra and eventually might affect attention and executive function.
Abstract P367: Brain-Wide Quantification of Amyloid in Transgenic Mice Using Volumetric Imaging and Automated Image Analysis
Authors: Schneider Lauren L , Irani Anaiza S , Ajay Apoorva , Plautz Erik K , Kong Xiangmei , Ramirez Denise M , Goldberg Mark P
Published: March 2021

Localizing and quantifying amyloid in three dimensions furthers understanding of spatial patterns of amyloid deposition and disease progression in experimental models of cerebral amyloid angiopathy (CAA). Serial two-photon tomography (STPT) is ideal for this purpose because it produces 3D datasets of the whole mouse brain in a matter of hours. We present an optimized pipeline for fluorescent whole-brain labeling of amyloid and vasculature, STPT imaging of labeled brains, machine learning-aided classification of vascular and parenchymal amyloid, registration of images to a standard reference atlas, and automated quantification of these signals across brain regions. We used traditional histological sectioning and slide mounted imaging to compare and optimize published methods of fluorescent amyloid and vascular labeling. An intraperitoneal injection of methoxy-X04 delivered the day before euthanasia was chosen to label amyloid. Cerebral vessels are visualized by transcardial perfusion of rhodamine-B isothiocyanate in gelatin. Labeled brains are imaged by STPT and rendered in 3D to appreciate regional amyloid distribution. Volumetric image datasets are quantified using a modification of our custom image analysis pipeline. Pixels are classified as vascular or parenchymal amyloid with supervised machine learning methods. Classified signals are registered into the Allen Institute for Brain Science Common Coordinate Framework version 3.0 for quantification. This strategy produces high resolution volumetric images amenable to automatic quantification of parenchymal and vascular amyloid deposits throughout the brain, appropriate for studies involving large numbers of experimental brains in rodent models of CAA.

Figure 1: A 3D rendering of prediction probability maps of a whole labelled mouse brain depicting fluorescent signals that were automatically classified as parenchymal amyloid (cyan), vascular amyloid (yellow) and brain parenchyma.
Abstract P369: Cerebral Small Vessel Disease and Enlarged Cardiac Ventricles
Authors: Navarro Kayla , Wong Ka-ho , Ibrahim Majd M , De Havenon Adam H , Goldstein Eric
Published: March 2021

Introduction:
White matter hyperintensities (WMH) are a radiographic marker for cerebral small vessel disease (CSVD). Conditions altering cerebral venous outflow such as elevated central venous pressure and right atrial pressure in individuals with cardiac valvular disease have been implicated in the development of WMH.

Hypothesis:
We hypothesize that increased right-heart chamber size in individuals without significant cardiac valvular disease is associated with worse WMH.

Methods:
A retrospective chart review of adults with a brain MRI and a 2-dimensional transthoracic echocardiogram (TTE) was performed. Worst burden of WMH by way of Fazekas score, either periventricular or deep white matter, served as the primary outcome. Statistical analysis was performed using a multivariate ordinal logistic regression model.

Results:
A total of 132 individuals were included. Right atrial area (OR 0.93, 95% CI 0.87 to 1.00, p = 0.0041), right ventricular internal diameter (OR 0.48, 95%CI 0.27 to 0.83, p = 0.008) and left atrial area (OR 0.93, 95%CI 0.88 to 0.98, p = 0.007) was identified as being significant. Cardiac functional markers were not significant, including tricuspid annular plane systolic excursion (OR 0.99, 95%CI 0.93 to 1.05, p = 0.670), right ventricular ejection fraction (OR 0.99, 95%CI 0.96 to 1.02, p = 0.670) and left ventricular ejection fraction (OR 0.99, 95%CI 0.96 to 1.02, p = 0.567). Analysis of isolated DWM or PVWM Fazekas scores did not find significant predictors in relation to cardiac structure or function.

Conclusions:
Through non-invasive cardiac imaging, we identified that cardiac structural abnormalities as opposed to functional abnormalities were associated with worse WMH. Mechanistically this may result from altered intracerebral arteriovenous coupling or a shared pathophysiologic pathway between WMH and coronary microvascular disease.
Abstract P37: Impact of Onset-To-Treatment Time on Hospital Discharge Destination After Aneurysmal Subarachnoid Haemorrhage - The REDDISH Study
Authors: BUSCOT Marie-Jeanne , Chandra Ronil V , Nichols Linda , Blizzard Leigh , Stirling Christine , Smith Karen L , Lai Leon , Asadi Hamed , Reeves Mathew J , Froelich Jens , Thani Nova , Thrift Amanda G , Gall Seana L
Published: March 2021

Background and aims:
Rapid access to specialised care improves outcomes after aneurysmal subarachnoid haemorrhage (aSAH) but there is limited evidence on the optimal time-to-treatment. We investigated onset-to-treatment time and hospital discharge destination in aSAH.

Methods:
Consecutive first-ever aSAH patients were retrospectively identified from multiple overlapping sources in two comprehensive cerebrovascular referral centres between 2010-2016. Onset-to-treatment time (hours from onset of symptoms to treatment to secure aneurysm), clinical characteristics, and neurological complications (NINDS classifications) were extracted by clinical data collectors from medical records. Among survivors, we estimated the effect of continuous onset-to-treatment on hospital discharge destination (i.e. home vs. rehabilitation/other hospital as proxy for functional recovery) using logistic regression with adjustment for gender, treatment type (clipping or coiling), hospital presentation (direct admission or transfer), and severity (World Federation of Neurosurgical Societies scale, modified Fisher scale). Non-linear effects were investigated using natural cubic splines.

Results:
Among 402 survivors at discharge, there was a strong non-linear effect of onset-to-treatment time on odds of being discharged home compared to discharge to rehabilitation independent of severity, gender, treatment type and transfer (see Figure). The greatest benefit to discharge home was evident with treatment at up to 12.5 hours but the benefit remained at up to 20 hours post-onset.

Conclusions:
aSAH Treatment occurring within 12.5 hours led to greater discharge to home. Our use of continuous modelling provides clarity around optimal treatment times for aSAH to guide clinical practice.
Abstract P372: Sex-Differences in Carotid Plaque Composition in Patients With Embolic Stroke of Undetermined Source
Authors: Song Jae W , Siegler James E , Thon Jesse , Woo John H , Cucchiara Brett L
Published: March 2021

Introduction:
Non-stenotic carotid plaque may be the cause of ischemic stroke in some patients with embolic stroke of undetermined source (ESUS). We examined sex-differences in carotid plaque composition in patients with ESUS.

Methods:
A retrospective cohort of anterior circulation acute ischemic stroke patients with CTA head/neck and meeting criteria for ESUS was identified. Carotid artery bifurcations (4cm segment) ipsilateral to the stroke were evaluated using a semi-automated segmentation software to measure total plaque volume and plaque subcomponents (calcium, intraplaque hemorrhage [IPH], and lipid rich necrotic core [LRNC]). Sex-differences in baseline vascular risk factors and plaque subcomponent volumes were tested by Mann-Whitney U tests or students t-tests for continuous variables and Fisher’s exact test for categorical variables. Associations of each plaque subcomponent were tested by multivariate linear regressions.

Results:
Of 94 patients, 55% were women. Mean age of the cohort was 65 years. Women had higher body mass indices than men (29.2 vs 26.3; p=0.02). There were no other significant differences in age or vascular risk factors between men and women. Overall plaque volume (p=0.001) was significantly greater in men as was the volume of calcification (p<0.001) and IPH (p=0.008) in carotid arteries ipsilateral to the stroke (Figure). No significant difference was detected in LRNC volume by sex (p=0.84). In multivariate analysis, male sex (β=45.9, 95% CI 18.0-73.7, p=0.002) and older age (β=1.85, 95% CI 0.73-3.0, p=0.001) were significantly associated with calcified plaque volume, and male sex (β= 6.7, 95% CI 2.6-10.8, p=0.002) with IPH. Neither age nor sex was significantly associated with LRNC.

Conclusions:
Sex-differences in carotid plaque composition in ESUS suggest the possibility of a differential contribution of non-stenotic carotid plaque to stroke mechanism in men versus women.
Abstract P373: Persistent Hyperintensity on Diffusion Weighted Imaging One Month After Stroke is Associated With Larger Ischemic Lesions and Greater Loss of Function
Authors: Khan Muhammad Taimoor , Adil Malik M , Kim Yongwoo , Lynch John K , Wright Clinton B , Leigh Richard
Published: March 2021

Background:
Diffusion weighted imaging (DWI) becomes hyperintense within minutes of ischemic insult to cerebral tissue. While apparent diffusion coefficient maps evolve rapidly during the days after ischemia, DWI typically remains bright for weeks to months after a stroke. This phenomenon is often referred to as “T2-shine through.” We sought to investigate factors that influence persistent hyperintensity on DWI.

Methods:
The study population included ischemic stroke patients who were admitted to two regional stroke centers and imaged with MRI <=4.5 hours from stroke onset and then again 30 days later. DWI images were independently reviewed for each time point. 30-day DWI images were compared to initial images and were rated accordingly: 1. absent hyperintensity, 2. mixed hyperintensity, 3. bright hyperintensity. Hyperintensity rating was treated as an continuous variable and compared with demographics, risk factors, laboratory values, imaging measurements, and outcome measures using univariate linear regression.

Results:
Thirty-one patients were included in the study; median age was 63 and 58% were women. Hyperintensity on DWI was absent at 30 days in 9 patients (29%), mixed in 11 patients (35%) and bright in 11 patients (35%). Greater DWI hyperintensity 30 days post stroke was associated with larger volume of the perfusion deficit on presentation (p=0.037) but not with core stroke volume (p=0.621) or mismatch ratio (p=0.719). DWI hyperintensity was not associated with demographic or clinical variables. Greater DWI hyperintensity rate was associated with worse post-stroke disability when comparing premorbid modified Rankin score (mRS) with the follow up mRS (p=0.026) as depicted in the figure that showing a box plot of change in mRS vs. degree of “T2-shine through”.

Conclusions:
Persistent hyperintensity on DWI a month after stroke may be an indicator of greater disability. Larger studies are needed to confirm these findings and understand their implications for further recovery.
Abstract P374: Dolichoectacic Features of Basilar Artery Serve an Imaging Surrogate of Branch Artery Disease in Patients With Pontine Infarcts
Authors: Oge Dogan Dinc , Arsava Ethem M , Topcuoglu Mehmet A
Published: March 2021

Background:
The arterial pathology underlying recent small subcortical infarctions (historically known as lacunar stroke) is heterogenous and includes lipohyalinosis, branch artery atherosclerosis or embolism. Although the use of high-resolution imaging studies directed to vessel wall might be helpful in teasing out these different pathologies, more readily available imaging surrogates such as size or spatial characteristics of the ischemic lesion are used for this purpose in clinical practice. Herein, we determined the distribution of dolichoectacic features of basilar artery in patients presenting with pontine penetrator artery stroke with different underlying occlusive pathologies.

Methods:
The dolichoectacic features of basilar artery were retrospectively evaluated according to Smoker’s criteria (diameter: >4.5 mm, laterality: more lateral to the lateral margin of clivus or dorsum sellae, and height of bifurcation: at least at the level of third ventricular floor) on CT angiography in ischemic stroke patients with a single penetrator artery occlusion in the pons. Patients with basilar artery pathologies such stenosis, dissection, or apparent dolichoectasia were excluded. Ischemic lesions extending to the surface of pontine base on DWI were judged to be secondary to branch artery occlusion, rather than lipohyalinosis.

Results:
Out of 122 patients, 68 (56%) had at least one feature suggestive of basilar artery dolichoectasia. Patients with lateral deviation of basilar artery were more likely to harbor infarcts extending to pontine surface (69% vs. 50%); no such relationship was identified for other imaging markers of dolichoectasia. After adjustment for age, gender and vascular risk factors, lateral deviation of the basilar artery remained significantly associated with an infarct pattern suggestive of branch artery occlusion (OR=2.8, 95%CI 1.1-7.3; p=0.031). There was also a tendency for ischemic lesions to be located on the ipsilateral side of the lateral deviation (63%; p=0.081).

Conclusion:
Our findings highlight that lateral displacement of basilar artery, an imaging feature of basilar dolichoectasia, can be used as an additional surrogate marker of branch artery pathology in patients with pontine penetrator artery infarction.