bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract TP542: EEG Detection of Secondary Worsening of Neuronal Function in Malignant MCA Infarction: Development of a Tool to Identify Patients for Decompressive Hemicraniectomy
Authors: Rubinos Clio , Yelisyeyev Andriy , Park Soojin , Agarwal Sachin , Roh David , Claassen Jan
Published: January 2019

Hemicraniectomy (HC) improves mortality in Malignant Middle cerebral artery Infarctions (MMI), but patient selection and optimal timing for HC remains unclear. A continuous method to monitor for the risk and development of herniation from infarction would allow a better selection of patients for HC We hypothesized that certain EEG features reflective of worsening mass effect will be easier to detect on quantitative EEG (qEEG) analysis trends We studied qEEG trends before, during clinical deterioration (drop in GCS by at least 3 points) and after administration of osmotherapy. qEEG trends included rhythmicity spectra 0-25 Hz (scale 0- 2uV/Hz), Color Density Power Spectra (CSA) 0-20Hz (scale 0-2uV/Hz), amplitude integrated EEG (aEEG): 0-100uV and VsRhythmicity spectrogram 1 - 25 Hz (-3-3 Zscore) Trends demonstrated bilateral loss of power on beta and alpha frequencies and increase in theta preceded clinical deterioration by approximately 1 hour (left > right). Patient2 subsequently had a robust theta power increase (+z score, red) in left > right hemisphere which coincide with clinical deterioration on vsRhythmmicity Spectrogram. Also, there was a decreased of fast and slow frequencies bands on rhythmicity spectrogram and CSA with a diffuse attenuation outlined by aEEG (Left > right). Following osmotherapy gradual improvement in all frequencies is seen but with an incomplete recovery in patient1 with lower alpha and theta power on right posterior and anterior quadrants suggested ongoing uncal and sub-falcine herniation, later confirmed on imaging Changes on qEEG reflecting impaired perfusion during acute herniation can manifest as decreased power in all frequency bands of varying severity prior to clinical deterioration. These changes can be completely or partially reversed with osmotherapy. Partial EEG response to osmotherapy may represent a potential sign of patients who will fail medical management and need DC. qEEG may be a helpful tool in HC patient selection
Abstract TP547: Peripheral Blood Indices for Platelet Reactivity and Systemic Inflammation Correlate With Coated-Platelet Trends After Aneurysmal Subarachnoid Hemorrhage
Authors: Ray Bappaditya , Hollabaugh Kimberly , Ford Lance , Dale George L , Prodan Calin I
Published: January 2019

Introduction:
Cerebral micro-thrombosis and neuroinflammation are important mechanisms causing delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). Apart from these local events, aSAH also mounts a systemic inflammatory response that may be reflected through various systemic markers. Mean platelet volume to platelet count (MPV:PLT), platelet count to lymphocyte count ratio (PLR), neutrophil count to lymphocyte count ratio (NLR) are established markers for platelet reactivity and systemic inflammation, respectively.

Hypothesis:
We assessed if peripheral blood indices (PBI) correlated with an established marker for platelet reactivity, coated-platelets, in predicting DCI after aSAH.

Methods:
A prospective cohort of 44 patients presenting with varying grades of aSAH were enrolled to assess coated-platelet levels in predicting DCI. Non-linear regression analysis was performed to assess the association correlation between coated-platelets and PBI trends in predicting DCI.

Results:
Twenty-nine (65.9%) of the enrolled patients developed DCI, and a higher rise in coated-platelets from patient’s baseline predicted development of DCI. Using non-linear regression models MPV:PLT showed a rise in ratio during the first 3 days followed by progressive decline. In contrast, PLR and NLR showed initial declines in their respective ratios until 4.2 and 5.8 days respectively followed by a gradual rise. Although slope differences for patients developing DCI as compared to those without DCI for MPV:PLT showed a trend towards significance (p=0.06), intergroup difference for PLR or NLR was not statistically significant. However, a significant relationship between MPV:PLT and coated-platelets (p<0.0001) was observed: with every unit rise in MPV:PLT ratio, coated-platelet levels increased by 0.04%. Similarly, a significant relationship was observed between PLR and coated-platelets (p=0.0001), with every unit rise in PLR, coated-platelets decreased by 2.06%.

Conclusion:
An early rise in MPV:PLT ratio with corresponding parallel rise in coated-platelet levels allude to presence of prothrombotic factors after aSAH. Also, a fall in PLR and NLR suggest a possible immunosuppressed state during the early phase after aSAH.
Abstract TP550: Clinical and Demographic Predictors of Cerebral Vasopasm Occurrence Following Sub-arachnoid Hemorrhages
Authors: Shpak Max , Cowperthwaite Matthew C , Nadasdy Zoltan , Waldron James
Published: January 2019

Introduction:
Cerebral vasospasm (CV) often follows aneurysmal subarachnoid hemorrhage (SAH) and, when severe, may lead to delayed cerebral ischemia (DCI) that can contribute substantially to morbidity and mortality. It is important to identify patients at high risk for DCI in order to allow for closer monitoring and timely treatment. This study analyzes the association of DCI with co-morbidities and demographic variables.

Hypothesis:
Diseases of the circulatory system may be predictive of DCI risk in SAH patients.

Methods:
Data from a total of 20039 SAH events between 2013 and 2018 were collected from 178 US hospitals. The occurrence of DCI during the SAH hospitalization was determined with ICD 9/10 diagnosis codes. Patient age was compared between the DCI and non-DCI SAH cases using t-tests. Odds ratios and Fisher exact tests were used to evaluate the relative incidence of DCI according to patient sex and the presence/absence of comorbidities and other clinical covariates (only those that occurred in at least 5% of SAH patients). Statistical significance of co-morbidities associated with DCI occurrence was evaluated following adjustment for false discovery rates.

Results:
In our cohort, 874 (4.36%) SAH patients experienced an episode of DCI. SAH patients with DCI were significantly younger than non-DCI SAH patients (DCI mean 60.40, non-DCI 66.95, p << 0.001), and there was a significantly higher relative incidence of DCI in female vs male patients (OR = 1.967, p << 0.001). Several co-morbidities were strongly associated with DCI occurrence, most notably hypoosmolality (OR=2.67), anemia (OR=2.15), hyperglycemia (OR=2.15), disorders of phosphorus metabolism (OR =2.55) and hyperlipidemia (OR=1.52), all with p << 0.001. In contrast, conditions such as hyperosmolality (OR=0.233), acidosis (OR=0.354), sepsis (0.393), diabetes (0.581) and kidney failure (OR=0.483) have a significant (p <<0.001) negative association with DCI. Hypertension does not appear to be significantly predictive of DCI or its absence.

Conclusions:
The data in this study suggest that age and sex are strongly predictive of DCI risk, and that several facets of an SAH patient’s metabolite and ion balance may either protect or predispose him/her to CV and DCI incidence.
Abstract TP57: Post-arrival Time Disadvantage for Patients Presenting Directly to Thrombectomy Sites
Authors: Shoirah Hazem , Stein Laura , Wheelwright Danielle , Tuhrim Stanley , Mocco J , Fifi Johanna
Published: January 2019

Background:
There is expanded focus on stroke systems of care, with emphasis on time to groin puncture (GP) for thrombectomy-eligible patients. For many tertiary networks, favorable time to GP is driven by transferred patients. Patients who present directly to thrombectomy capable sites are at a time disadvantage. There is little information about the specific differences between those populations to inform policy changes.

Methods:
We analyzed all patients who underwent emergent endovascular thrombectomy (EVT) between July 2017 and June 2018 in a large tertiary network. We divided patients based on mode of arrival to direct presentation (DP) to treating site vs transfer (TT) from spoke hospital. We compared baseline characteristics and different time epochs in post-arrival patient workflow.

Results:
A total of 155 patients underwent EVT; 52 in the DP and 80 in the TT cohorts. 23 patients were in-house activations and were excluded. The TT cohort had shorter time from arrival to groin puncture 58.82 ± 25.9 vs 142.72 ± 66.45 mins (p = 0.0001). The TT cohort also had shorter image acquisition time 5 ± 8 vs 35 ± 54 mins (p = 0.0001) with more patients in DP cohort undergoing CTA (absolute difference 73.74%, 95% CI 61.12-82.13, p <0.0001). TT had shorter time from image acquisition to arrival in the angiography suite (17.0 ± 9.0 vs 67.0 ± 35.0, p = 0.0001). In DP patients, the arrival to stroke team notification time was 15.78 ± 42.26 mins and stroke to endovascular team notification time was 36.54 ± 36.59 mins. There was no difference between the cohorts in other time epochs (e.g. hospital arrival to CT or room arrival to groin puncture), the rate of tPA utilization, or the proportion of patients undergoing general anesthesia, however tPA was given pre-arrival in all patients in the TT cohort.

Conclusion:
Time to GP is longer in DP vs TT patients. The difference is driven by the back-loading of diagnostic studies (e.g. CTA) and systemic thrombolysis, delay in endovascular team activation and resultant lack of angiography suite readiness. Strategies that aim at earlier endovascular team activation could ameliorate the difference, especially as field triage and bypass to thrombectomy sites becomes wide-spread.
Abstract TP575: Amyloid Accumulation Evaluated With Pib Pet in Patients With Cerebral Amyloid Angiopathy
Authors: Hasegawa Itsuki , Abe Takato , Mino Toshikazu , Takeuchi Jun , Itoh Yoshiaki
Published: January 2019

Purpose:
Cerebral amyloid angiopathy (CAA) is a disease with deposition of amyloid beta protein to meninges or intracerebral vessel walls. CAA is known as a cause of cerebral hemorrhage or subarachnoid hemorrhage occurring most frequently in the occipital lobe. CAA is usually accompanied with Alzheimer's disease, which shows specific pattern of amyloid accumulation. In this study we evaluated the distribution of the amyloid deposition in CAA patients using PIB-PET.

Methods:
Five patients, 3 males and 2 females, who developed cerebral hemorrhage or subarachnoid hemorrhage and clinically diagnosed as CAA were evaluated. Age of the patients was 28 - 74 years old. To detect amyloid accumulation, we injected 250-350mBq or 400-500mBq of [11C]PiB, followed by 60 minutes or 70 minutes dynamic scan using Eminence B PET camera (Shimadzu Corporation).

Results:
PIB accumulation was detected predominantly in the frontal lobe, parietal lobe, and lateral temporal lobe, but much less in the occipital lobe. The distribution of PIB accumulation was mostly similar to that in patients with Alzheimer disease. Little accumulation in the occipital lobe may reflect apparent effects of intracerebral hemorrhage.

Conclusion:
In most CAA patients, the examination by PIB-PET fails to detect amyloid deposition in the vessel walls of the occipital lobes. Instead, it more frequently reflect intracerebral amyloid deposition of accompanying Alzheimer's disease.
Abstract TP579: Ratio of Arteriovenous Malformation Draining Vein to Adjacent Venous Sinus Diameter is Associated With Increased Risks of Vein Stenosis
Authors: Brunozzi Denise , Amin-Hanjani Sepideh , Charbel Fady T , Mohammaden Mahmoud H , Andrews Amanda , Alaraj Ali
Published: January 2019

Introduction:
Venous outflow stenosis in cerebral arteriovenous malformation (AVM) remains the main risk factor associated with AVM rupture. The hemodynamic process underlying the development of venous outflow stenosis is poorly understood. Here, we compared the location of stenosis within the draining vein of the AVM in relation to the adjacent venous sinus and explored the hypothesis that the ratio of draining vein to adjacent sinus diameter might predict the development of venous stenosis.

Methods:
Patient demographic parameters, and cerebral angiograms of 290 patients with supratentorial AVMs seen at our institution between 1997 and 2018 were reviewed. AVM draining vein and adjacent venous sinus diameters, degree of draining vein stenosis, and distance (mm) from the stenotic point of the draining vein to the junction of the adjacent draining sinus were recorded. The correlation between percentage of AVM draining vein stenosis and the ratio of venous sinus to AVM draining vein diameters was analyzed.

Results:
247 AVMs in 242 patients with complete angiographic data were included, and a total of 361 draining veins were measured. Venous stenosis was present in 131 draining veins (36.3%). Venous stenosis was observed within 20 mm of the junction to the adjacent major draining sinus in 85% of our sample (Fig 1A). The ratio of draining vein to adjacent sinus diameter correlated positively with the percentage of venous stenosis (P=0.0001, r=0.21; Fig 1B).

Conclusion:
AVM venous outflow stenosis is observed closer to the adjacent venous sinus junction. The degree of venous stenosis is greater when the ratio of AVM draining vein/adjacent venous sinus diameter approaches or is larger than 1. This may be related to more turbulent flow at the junction of the draining vein and venous sinus, especially in larger draining veins, thus leading to venous stenosis with time. Further studies are needed to explore the pathophysiology of venous stenosis.
Abstract TP589: Emergency Medicine Physicians Can Reliably Treat Stroke Patients with tPA Using a Checklist
Authors: Berekashvili Ketevan , Zha Alicia M , Zhang Xu , Abdel-Al Mohammed M , Soomro Jazba H , Prater Samuel J , Grotta James C
Published: January 2019

Background:
There is uncertainty among many emergency medicine physicians about the decision to give intravenous tissue-type plasminogen activator (tPA) in suspected acute ischemic stroke patients, which limits its use. A checklist approach has been suggested as a solution.

Objective:
To compare agreement on tPA treatment in suspected acute ischemic stroke patients between vascular neurology and emergency medicine physicians using a checklist.

Methods:
Every suspected acute stroke patient brought to our comprehensive stroke center emergency room within 4.5 hours from symptom onset was prospectively evaluated simultaneously and independently by vascular neurology fellows (VNF) and emergency medicine residents (EMR). The latter used a tPA screening checklist, which included guideline exclusion criteria to help with their treatment decision. Agreement between the EMR and the VNF and a senior VN faculty was determined using Cohen’s kappa (κ) statistics.

Results:
Over 5 months, 60 patients were enrolled, age 63±16, 50% female, NIHSS median 6 (IQR: 1,14), premorbid mRS
>
2 30%. Eventual etiology was: 10% large vessel atherosclerosis, 18% cardioembolism, 12% small vessel, 12% cryptogenic, and 48% mimic. 25 (42%) were deemed tPA eligible by the EMR, 18 (30%) by the VNF, and 22 (37%) by the VN faculty. Agreement was substantial between EMR and VNF (κ=0.68, 95% CI 0.49 to 0.87) and between EMR and VN faculty (κ=0.69, 95% CI 0.50 to 0.87]). Age, NIHSS, premorbid mRS, gender and race had no effect on agreement. There were no complications in any tPA treated patients. Stroke mimics were the main cause of disagreement between EMR and VNF (κ=0.24, 95% CI -0.15 to 0.63) and between EMR and VN faculty (κ=0.35, 95% CI -0.08 to 0.78).

Conclusions:
Our data suggest that with the aid of a checklist, emergency medicine physicians can reliably treat acute stroke patients with tPA. Areas for improvement include recognition of stroke mimics. Further studies are warranted to evaluate checklist enhanced tPA treatment in order to allay emergency medicine physician uncertainty and expand the use of tPA.
Abstract TP62: Acceleration-Selective Asl Perfusion Imaging as an Alternative for Dsc in an Acute Stroke Population
Authors: De Vis Jill , Bokkers Reinoud , Luby Marie , Schmid Sophie , van Osch Matthias , Latour Larry
Published: January 2019

Introduction:
Differentiation of core, penumbra, and benign oligemia (based on capillary perfusion) is of increasing importance in treating acute ischemic stroke (AIS). Both CT and DSC perfusion MRI rely on similar kinetics which may be influenced by arrival delay. Arterial spin labeling (ASL) MRI serves as a non-invasive alternative but similarly suffers from delayed arrival. Here we explore acceleration-selective ASL (accASL), a method not dependent on arrival delay, for identifying regions of critically low perfusion.

Methods:
Forty-four patients with AIS and pre-treatment MRI including DWI, DSC and accASL MRI were included in this study. Perfusion and diffusion lesions were qualitatively and quantitatively (i.e. through manual delineation) rated on blinded DSC-DWI and AccASL-DWI image pairs. The mean transit time (MTT) map was used for DSC perfusion evaluation.

Results:
Only 43 patients were included in our analysis due to uninterpretable MTT maps in one patient. A perfusion lesion was identified on 38 of the MTT maps and 32 of the accASL images. The mean perfusion lesion volume was larger (p<0.001) on MTT than on the accASL images; 120 (±103) versus 32 (±52) ml, respectively. The mean lesion on DWI was 10 (±13) ml, and accASL detected perfusion deficit related better to DWI lesion than MTT (R
2
of 0.20 and 0.08, respectively). MTT identified a perfusion lesion in 8 patients where accASL did not. The median MTT perfusion lesion in these patients was 103 (3-198) ml and the median DWI lesion volume was 2 (0-7) ml. Two patients demonstrated a perfusion deficit on the accASL images (5 and 49 ml) but not on the MTT images, the DWI lesion volume in these patients was 1 and 2 ml.

Conclusion:
AccASL could identify a perfusion deficit in more than 75% of patients with a perfusion deficit on the MTT maps. Lesions on accASL images were closer in volume to those seen on DWI, suggesting a more specific measure of ischemia that is less influenced by delays due to proximal occlusion or stenosis. Future work will investigate the relation between accASL perfusion deficit and final infarct.
Abstract TP65: Perfusion Artifacts May Overestimate Thrombectomy Eligibility in Patients With Acute Large Vessel Occlusion
Authors: Siegler James E , Pulst-Korenberg Johannes , Olsen Andrew , Rosenberg Jon , Cristancho Daniel , Raab Lindsay , Woo John , Cucchiara Brett , Messé Steven
Published: January 2019

Background:
Automated computed tomography perfusion (CTP) is effective at identifying salvageable penumbra in patients with acute ischemic stroke due to large vessel occlusion (LVO). Perfusion imaging is now recommended for the selection of thrombectomy candidates in the extended window (>6 hours) which may incorporate the penumbra mismatch ratio (T
max
>6s:rCBF<30%) >1.7. However automated perfusion output may include artifactual findings that are discordant with a patient’s symptoms and vessel imaging, overestimating the tissue at risk.

Hypothesis:
Artifactual findings on automated CTP penumbral assessment (T
max
>6s) will misclassify thrombectomy eligibility in some patients.

Methods:
We reviewed a retrospective multi-site consecutive cohort of patients undergoing CTP for suspected acute ischemic stroke ≤24 hours from onset (6/2017-12/2017). The primary outcome was the volume of any discordant T
max
>6s abnormality on RAPID automated perfusion CT imaging, calculated by two independent readers using manual assessment (ImageJ, NIH). The discordant penumbral volume was compared to the automated output and corrected mismatch ratios were generated.

Results:
Of 410 consecutive patients who underwent CTP, 60 (14.6%) had acute LVO of the anterior circulation and were included. The median age was 78 years (IQR 64-84), 36 (60.0%) were female, and 25 (41.7%) were White. Fifteen patients (26.3%) had T
max
>6s abnormalities that were discordant with the clinical symptoms or anticipated vascular distribution, with strong inter-rater agreement (r
2
=0.927). The median difference between manual and automated T
max
>6s volumes was 18.4cc (IQR 10.80-35.77) accounting for 11.3% of the automated volume (IQR 7.8-46.7%). Following manual recalculation of the T
max
>6s volume, 1 patient was reclassified as having an “unfavorable” mismatch ratio (1.7%, 95%CI 0.2-11.5%).

Conclusion:
About one quarter of patients had discordant penumbral imaging on automated CTP, which may lead to misclassification of thrombectomy eligibility. While artifactual findings are reliably identified by trained raters, our results emphasize the need to evaluate CTP results with knowledge of the patient’s clinical symptoms and vascular imaging.
Abstract TP70: Collateral Scoring of Cerebral Arteries Predicts Perfusion and Diffusion in Acute Ischemic Stroke Patients Undergoing Thrombectomy
Authors: Shah Varun , Hoang Nguyen , Dornbos David , Schunemann Victoria , Nimjee Shahid , Youssef Patrick , Powers Ciaran
Published: January 2019

Introduction:
The Rapid processing of Perfusion and Diffusion (RAPID) system for automating perfusion and diffusion data from head computed tomography (CT) perfusion imaging has improved acute ischemic stroke treatment by quickly and accurately identifying those patients who may benefit from thrombectomy. Collateral scoring (CS) of cerebral arteries using CT angiography (CTA) has proven useful in predicting post-intervention infarct volumes and functional outcomes in ischemic stroke patients. Here we evaluate the relationship between CS and RAPID in an effort to augment triage and provide improved predictability of functional outcomes in ischemic stroke patients.

Methods:
We retrospectively reviewed all patients with large anterior circulation occlusions who underwent RAPID imaging, CTA imaging and thrombectomy from July 2017 to July 2018. The final cohort included 37 patients. Charts were reviewed for baseline characteristics, RAPID data, and CS based on CTA. A CS score of 0 = absent collaterals in > 50% of the superior or inferior ipsilateral M2 distribution, 1 = diminished collaterals in > 50% of an M2 distribution, 2 = diminished collaterals in < 50%, 3 = equal collaterals, and 4 = enhanced collaterals. Additional outcome data, including modified Rankin Score (mRS), and procedural data were collected as well. Post-intervention penumbra volume was calculated on MRI (CT if no MRI was available) using the ABC/2 method. Analysis of Variance (ANOVA) was used to identify significant correlations between CS and other variables.

Results:
Univariate analysis revealed a significant negative correlation between CS and brain volume with cerebral blood flow (CBF) < 30% of original (p = 0.001), between CS and cerebral volume with perfusion delay > 6 seconds (Tmax) (p=0.044), and CS and discharge mRS (p=0.041). When controlling for successful revascularization, defined as TICI 2b and 3, post-intervention penumbra volume (p=0.0028) and discharge mRS (p=0.039) negatively correlated with CS.

Conclusion:
CS on CTA may be another way to identify patients who would benefit from mechanical thrombectomy and predict functional outcomes post-intervention. CS may allow the stroke team to optimize the care of patients who may not be able to get RAPID analysis.
Abstract TP77: Collateral- vs Perfusion-Based Selection Paradigm of Late Window (6-24 hours) Patients With Acute Ischemic Stroke a Comparative Study of Decision Making Using Multi-Phase CTA and CT Perfusion
Authors: Almekhlafi Mohammed A , Kunz Wolfgang , McTaggart Ryan , Najm Mohammed , Shankar Jai Jai , Khaw Alexander , Fainardi Enrico , Rubiera Marta , Jayaraman Mahesh V , Hill Michael D , Demchuk Andrew , Goyal Mayank , Menon Bijoy K
Published: January 2019

Purpose:
To compare the performance of collateral- vs perfusion-based imaging paradigms in late window stroke patients.

Methods:
In the prospective international (PRove-IT) study, patients had baseline CT head, multi-phase CTA (mCTA) and CTP. Patients presenting 6-24 hours of onset were included. We retrospectively selected patients for EVT based on 1) Collaterals: ASPECTS ≥5, plus proximal intracranial occlusion, plus good mCTA collaterals; 2) Perfusion: using DEFUSE-3, or DAWN trial criteria. CTP was processed using RAPID software. The performance of each paradigm to predict outcomes was assessed using the area under the receiver operating characteristic curve (AUC) of logistic regression models adjusting for age, NIHSS, sex, onset to CT time, EVT treatment, and interaction of EVT and the imaging paradigm.

Results:
We included 83 patients; medians of age 71, NIHSS 12, ASPECTS 9, and onset/ last seen well to CT of 576 minutes. Occlusions were: ICA, M1, M2-MCA (81.9 %), distal (8.4%) and none (9.6%). 35 patients received EVT (all without IV tPA), 10 IV tPA, and 38 treated conservatively. TICI 2b-3 was achieved in 71.4% of EVT patients. mRS≤2 at 90 days was achieved in 47% (51.4% with EVT: 72% of TICI2b/3 patients). Table 1 shows 90-day mRS according to the imaging paradigm for the entire cohort. Among 10 patients who were EVT-eligible according to mCTA but not DEFUSE-3, 70% achieved mRS≤2. Among 31 who were EVT-eligible per mCTA but not DAWN, 61% achieved mRS≤2. For 5 patients who were EVT-eligible per DEFUSE-3 but not mCTA, 60% achieved mRS≤2. No patients were EVT-eligible per DAWN but not per mCTA. All paradigms had comparable AUCs for 90-day mRS≤2. In the EVT subgroup, mCTA had AUC of 0.80 vs 0.79 for DAWN, and 0.78 in DEFUSE-3 paradigms.

Conclusion:
The mCTA-defined collateral paradigm performs similarly well for EVT selection in the late time window. It also may include additional patients with possible benefit from ECT who would have been excluded by CTP-based imaging selection.
Abstract TP85: Accuracy of “At Risk” Tissue Predictions Using CT Perfusion in Acute Large Vessel Occlusions
Authors: Lee Songmi , Yoo Albert J , Berkhemer Olvert A , Majoie Charles B , Dippel Diederik W , Sheth Sunil A ,   MR CLEAN Investigators.
Published: January 2019

Accuracy of “At Risk” Tissue Predictions using CT Perfusion in Acute Large Vessel Occlusions Songmi Lee, Albert J. Yoo, Olvert A. Berkhemer, Charles B. Majoie, Diederik W.J. Dippel, Sunil A. Sheth, for the MR CLEAN Investigators. Background: CT Perfusion (CTP) determinations of salvageable tissue are increasingly used in patient selection for endovascular stroke therapy (EST). However, the validity of CTP predictions of expected infarction volume without rapid recanalization from EST (“at risk” tissue) remains poorly characterized.

Methods:
From the multicenter randomized MR CLEAN trial, we included patients who underwent CTP without successful recanalization (randomized to medical therapy or to EST with failed reperfusion). “At risk” volumes were based on Tmax > 6 seconds and infarct core on relative CBF < 30 (Olea Sphere, Le Ciotat, France). Primary outcomes were follow-up infarct volume (FIV) on CT at 1 to 5 days, and 90-day mRS. Data are presented as median [IQR] or OR [95% CI] unless otherwise specified.

Results:
Among 37 patients that met criteria for this study, 14 (38%) were women and age was 61 years [IQR 52-69]. NIHSS was 19 [IQR 15-21], ASPECTS 8 [IQR 7-9], and time from onset to presentation 160 minutes [IQR 39-200]. Occlusion location was M1 for 22 (59%), ICA-T in 11 (30%), and M2 in 4 (11%). “At risk” volume was 85 mL [IQR 71-115], infarct core was 7 mL [IQR 0.2-23] and mismatch was 79 mL [IQR 51-95]. FIV of < 60 mL was predicted in 7 patients, among whom 4 (57%) had > 90 mL FIV. In univariate analysis, “at risk” volume correlated poorly with FIV (r=0.08, p=0.65). In linear regression adjusted for age, onset to presentation and occlusion location, presentation NIHSS but not “at risk” volume predicted FIV (Coef 12, p<0.05; Coef -0.15, p=0.8). In similarly adjusted logistic regression, presentation NIHSS but not “at risk” volume predicted mRS 0-2 at 90 days (OR 0.7 [0.5-0.99]; OR 1.02 [0.99 - 1.05]).

Conclusion:
Predictions of “at-risk” tissue using CTP may underestimate the natural history of infarction from acute large vessel occlusions. An NIHSS-ischemic core mismatch may perform better as a predictor of clinical outcomes in patients without rapid recanalization.
Abstract TP91: Perfusion-weighted Magnetic Resonance Imaging is a Poor Indicator of Hemodynamic Compromise in Vertebrobasilar Disease
Authors: Stapleton Christopher J , Du Xinjian , Thulborn Keith R , Charbel Fady T , Amin-Hanjani Sepideh
Published: January 2019

Introduction:
Perfusion-weighted magnetic resonance imaging (MRP) has been used to assess changes in cerebral perfusion attributable to vascular stenosis or occlusion that may predict stroke risk. The ability of MRP to identify hemodynamic compromise in the posterior circulation, however, has not been well established. The observational Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study has previously demonstrated that flow status determined through large vessel flow measurements with quantitative magnetic resonance angiography (QMRA) predicts stroke risk in vertebrobasilar disease. We examined whether MRP parameters correlated with QMRA assessment of flow compromise in the VERiTAS cohort.

Methods:
VERiTAS enrolled patients with recent vertebrobasilar transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral and/or basilar arteries. Hemodynamic status using vertebrobasilar large vessel flow was measured using QMRA, and patients were designated as low or normal flow based on distal territory regional flow, incorporating collateral capacity. Dynamic susceptibility contrast MRP was performed concurrently with QMRA. Mean transit time (MTT) in the posterior cerebral artery (PCA) territory was used to evaluate posterior circulation perfusion. To normalize the values, an MTT ratio was calculated in reference to the anterior circulation (mean of the anterior cerebral artery (ACA) and middle cerebral artery (MCA) territories). The PCA to ACA/MCA MTT ratio from MRP was then assessed relative to flow status (normal vs. low) from QMRA.

Results:
Of the 72 enrolled subjects, 23 had MRP data available for review. On initial QMRA designation, 19 subjects were designated as normal flow vs. 4 as low flow. The mean MTT ratios for patients with normal vs. low flow were 1.02 (SD=0.05) vs.1.04 (SD=0.04), respectively (p=0.55, t test; p=0.50, Wilcoxon rank sum test). Among the subgroup of 23 patients, 1 patient with low flow, and MTT ratio of 1.00, experienced a recurrent stroke.

Conclusions:
These results suggest that MRP is a poor indicator of actual hemodynamic compromise in vertebrobasilar disease and is not a reliable substitute for large vessel flow measurements.
Abstract WMP107: Cerebrospinal Fluid Leukocyte Subtypes After Intraventricular Hemorrhage: An Analysis of the CLEAR-III Trial
Authors: Gusdon Aaron M , Quirk Kendel , Mayasi Yunis M , Betz Joshua , Hanley Daniel F , Ziai Wendy
Published: January 2019

Background:
Intracerebral hemorrhage (ICH) results in significant mortality and morbidity and initiates a cascade of inflammatory cell activation. Leukocyte subtypes have different effects, with monocytes contributing to increased hematoma expansion and mortality and neutrophils decreasing hematoma expansion. However, the response of cerebrospinal fluid (CSF) leukocytes to ICH with IVH has not been investigated.

Methods:
We retrospectively analyzed CSF and serum leukocyte counts from patients enrolled in CLEAR-III. After correction for CSF red blood cell (RBC) counts, data were plotted chronologically. Linear mixed-effects models were used to assess the differences in leukocyte subtypes after intraventricular saline or alteplase. Generalized linear models are being created to assess the relationship between CSF leukocyte subtypes and IVH volumes and 30, 60, 90, and 180-day outcomes.

Results:
Data were available for 237 and 228 patients in the saline and alteplase groups, respectively. Serum total white blood cell (WBC) and neutrophil counts increased after ICH, peaking at two days. Significant increases occurred in serum monocyte and lymphocyte counts, peaking at 6 and 10 days, respectively. Intraventricular alteplase had no effect on serum leukocyte counts. Peak CSF leukocyte counts occurred on day 1 after IVH (pretreatment) in the saline group. However, intraventricular alteplase resulted in a significant increase in WBC (
P
=0.0001), neutrophil (
P
=0.0003), monocyte (
P
=0.0064), and lymphocyte counts (
P=
0.0339), peaking two days after starting treatment. No significant associations between peak serum or CSF cell counts and 30, 180, and 365 day modified Rankin Scale were found.

Conclusions:
ICH drives an increase in serum leukocyte counts. Intraventricular alteplase results in an increase in all CSF leukocyte subtypes. Further work will be presented on the complex interactions between leukocyte counts, ICH severity, and outcomes.
Abstract WMP110: Catchy Acronym Improves Compliance in Hospital Struggling With Dysphagia Screening and NIHSS Assessment Upon Admission
Authors: Bannon Annette N , Eriks Penny S , Weiss Erin K
Published: January 2019

Background and Issues:
A hospital in a Chicago suburb struggled with inconsistent dysphagia screening and National Institute of Health Stroke Scale (NIHSS) assessment upon admission for patients coding out as a confirmed stroke patient. Percentage of compliance for dysphagia and NIHSS were, in 2014, 79% and 84%, respectively.

Purpose:
The purpose of this Quality Improvement (QI) Project Abstract was to increase the number of stroke patients assessed for dysphagia and NIHSS upon admission.

Methods:
A sample size of approximately 90 patients over a three month period was used to identify admission diagnoses of patients that were not assessed for dysphagia and NIHSS upon arrival but did code out for stroke.

D

izziness,

A

ltered mental status,

a

trial fibrillation,

W

eakness and

S

yncope were the five diagnoses consistently utilized. It was recognized that patients admitted with these diagnoses needed to be routinely assessed. To help staff remember these five diagnoses, an acronym (
DAaWS
) was developed. Communication to staff of the new DAaWS acronym and practice began in 2015 and consisted of visual learning tools, staff meeting discussions, just-in-time learning, rounding to influence and 1:1 education.

Results:
Data from 2013 showed an average NIHSS at 90% / dysphagia at 76%. 2014 showed an average NIHSS at 84% / dysphagia at 79%.
Implementation year of DAaWS practice, 2015 showed an average NIHSS at 91% / dysphagia at 94%.
2016 showed an average NIHSS at 97% / dysphagia at 90%. 2017 showed an average NIHSS at 96% / dysphagia at 84%. Of note is the 15% improvement of dysphagia from year 2014 to 2015 when the DAaWS practice began. Implementation of DAaWS had less impact on the NIHSS compliance in the initial year of 2015 with an increase of 7%. Subsequent years of 2016/2017 have seen an average increase in compliance of 12.5% from the 2014 data.

Conclusion:
In conclusion, the study showed that implementing a catchy acronym, DAaWS, to assist the nurse with early identification of potential stroke patients significantly improved the compliance of the dysphagia screening & NIHSS assessment upon admission.
Abstract WMP113: Improvement of Door-to-Groin Puncture Times in Stroke Codes
Authors: Uppal Avneesh K , Rutherford Wendy , Erickson Sheila
Published: January 2019

Background:
Stroke is the leading preventable cause of disability in the United States and the 5th leading cause of death. There are approximately 800,000 strokes each year. In 2010, the estimated cost of stroke was $34 billion. Regional targets for door-to-treatment times of patients with acute ischemic stroke have become more stringent as re-establishing blood flow quickly in these patients is the key to positive results. Based on evidence from recent endovascular trials, the San Diego County Stroke Consortium set the target for Door-to-Groin Puncture time ≤ 90 minutes in 50% of cases with proven large vessel occlusion. Although Sharp Grossmont Hospital (SGH) has had a long-established process of rapid triage, evaluation and management within the Emergency Department and In-House, the lack of consistency among responders necessitated establishing a standardized work flow.

Purpose:
A performance improvement plan was developed and initiated in November 2016 to improve the time to endovascular therapy for patients having a stroke.

Methods:
The following revisions were made to current practice: created the role of the Stroke Code Nurse; created Stroke Code algorithm; developed a Stroke Code criteria checklist; utilized Telestroke; implemented a feedback loop to Stroke Code team reporting imaging and treatment times along with patient outcomes. A specially trained team of 9 RNs provides 24 hour coverage for Stroke Codes, both In-House and in the ED. The Stroke Code Nurse acts as code leader/timekeeper and liaison between multiple departments, thereby decreasing the time it takes to send qualified patients to Interventional Radiology.

Results:
SHG's Door-to-Groin Puncture ≤ 90 minutes improved from 46% to 60%, surpassing the regional target of 50%, while also seeing an increase from 37 cases in 2015 and 41 cases in 2016 to 57 cases in 2017.

Conclusion:
Implementing the Stroke Nurse Role and creating a standardized work flow resulted in better identification of stroke patients due to the expertise of the Stroke Nurse, and faster imaging and treatment times. Implementing this process improvement plan provided patients with the highest quality care.
Abstract WMP115: Selection Criteria for Thrombectomy in Pediatric Stroke: A Single-Center Series
Authors: Lee Sarah , Heit Jeremy J , Albers Gregory W , Wintermark Max , Elbers Jorina , Bernier Eric , Jiang Bin , Marks Michael P , Do Huy M , Dodd Robert
Published: January 2019

Introduction:
The newly-extended time window for endovascular therapy represents a major opportunity for stroke treatment in children, for whom diagnosis is often delayed. However, no guidelines exist to determine how best to select children for thrombectomy, or if it is beneficial. We report all children presenting to our institution with large vessel occlusion (LVO), outline our criteria for thrombectomy, and discuss imaging and outcomes in this unique population.

Methods:
We reviewed prospective data on all patients < 18 years presenting with LVO. Demographic, clinical, imaging and outcome data were documented for each patient. Key inclusion criteria for thrombectomy were 1) NIHSS ≥ 6; 2) last known well (LKW) < 24 hours prior; 3) imaging suggestive of eloquent tissue at risk (diffusion-perfusion mismatch on MRI or ASPECTS >7 on CT).

Results:
Nine children presented acutely with stroke symptoms and an LVO; clinical and imaging data are shown in Table 1. All patients met clinical criteria for thrombectomy (NIHSS ≥ 6, LKW <24 hours). Four patients had CT or MR perfusion imaging. Two patients were deemed ineligible by neuroimaging criteria; one due to a matched lesion, and one due to low ASPECTS. Two illustrative cases are shown in Figure 1. Majority of strokes (66.7%) were cardioembolic. The two untreated patients had significant disability at follow-up.

Conclusion:
Perfusion imaging is feasible in pediatric stroke and may help identify salvageable tissue in extended time windows. Applying strict criteria to determine endovascular eligibility may lead to better outcomes in children, though further studies evaluating optimal perfusion thresholds in children are needed.
Abstract WMP14: e-ASPECTS Improves Sensitivity to Early Ischemic Injury on Acute Computed Tomography Scans
Authors: Chriashkova Julia , Menon Nisha , Chakrabarti Annie , Guyler Paul , Kelavkar Shyam , Kuhn Annalu , Kulikovski Johann , Koduri Gouri , Harston George , Haq Inam , Podlasek Anna , Roffe Christine , Alvarez Carlos , Vani Kavita , Wagner Viola , Walter Silke , Grunwald Iris
Published: January 2019

Background:
ASPECTS (Alberta Stroke Program Early CT Score) is a validated scoring system for assessment of early ischemic change (EIC) on CT head scans, which can be used to guide patient management and improve diagnostic accuracy. Detection of EIC can be challenging particularly for less experienced clinicians. e-ASPECTS software uses machine learning algorithms to support physicians in detecting EIC, which can be quantified using the ASPECTS score.

Hypothesis:
e-ASPECTS shortens time for CT scan assessment and improves agreement with reference standard ASPECTS when compared to blinded assessment.

Methods:
26 clinicians (including 11 radiologists, 6 junior and 7 consultant stroke physicians, and 2 non-specialist physicians) independently scored 2560 ASPECTS regions from 64 patients for signs of EIC on non-contrast CT brain scans. These were acquired within 4.5 hours of stroke onset. A familiarization training set of 5 patients was used prior to scoring. Images were randomized to manual or software assistance. After two weeks images were rescored using the alternative method. Scorers were blinded to clinical symptoms. Reference standard scores were defined by an independent neuroradiologist with information on clinical symptoms, access to 24h follow-up, and with CT perfusion or MRI scans when available.

Results:
Mean NIHSS was 11. Mean time to score scans fell by 34% (45s, 2:12 to 1:27, mm:ss) using e-ASPECTS assistance. Rater agreement with ground truth was greatest in the radiologist cohort, but performance improved across all clinician categories using e-APSECTS assistance (radiology kappa: 0.26 to 0.38). Sensitivity to EIC improved by a factor of two across all clinician groups using e-ASPECTS assistance, and this was most marked for less experienced physicians.

Conclusion:
In acute ischemic stroke e-ASPECTS assisted analysis increased accuracy and reduced time for detection of EIC. Routine assistance of non-contrast CT interpretation has the potential to reduce treatment times and improve accuracy across clinicians and sites.
Abstract WMP16: Artificial Intelligence Detection of Cerebrovascular Large Vessel Occlusion - Nine Month, 650 Patient Evaluation of the Diagnostic Accuracy and Performance of the Viz.ai LVO Algorithm
Authors: Chatterjee Arindam , Somayaji Nayana R , Kabakis Ismail M
Published: January 2019

Introduction:
Prompt and accurate identification of Large Vessel Occlusion (LVO) for Acute Ischemic Stroke (AIS) by CTA is essential for optimal endovascular reperfusion therapy. The Viz.ai algorithm (Viz LVO) was developed to process head and neck CTAs using a convolutional neural network artificial intelligence platform to identify anterior circulation LVOs from the ICA-T to the sylvian MCA M1 segments. We evaluated the diagnostic accuracy and notification time of Viz LVO compared with our institutional standard of care.

Methods:
Consecutively acquired CTAs performed for suspected AIS between 3/1/2016 and 11/30/2017 were identified for inclusion. No studies were excluded from analysis to reflect our institutional prevalence of anterior circulation LVOs. The CTAs were evaluated by the Viz-AI-Algorithm® v4.1.2. The processing time and automated LVO detection were recorded. These were compared against the radiology report, the radiologist to stroke care team time-to-notification, as well as an independent review of all studies by a neuroradiologist for secondary findings that may influence the accuracy of Viz LVO.

Results:
Analysis of 650 CTAs performed for AIS was conducted for 650 patients. The mean patient age was 66 (SD 15), 51% were female, and 30% of all studies were positive for anterior circulation LVO. Viz.ai demonstrated a sensitivity of 82%, specificity of 94%, PPV of 77%, and NPV of 95%. There were 31 false positives (16 due to intracranial atherosclerosis) and 23 false negatives reported by Viz.ai. Forty one cases were not processed due to metal artifact, inadequate contrast, motion artifact, or excess z-spacing variability. The mean processing time for Viz.ai was 5 minutes with a maximum of 8 minutes for all studies. The mean clinical standard-of-care notification time at our institution was 32 minutes with a maximum of 116 minutes.

Conclusion:
To the best of our knowledge, this is the first AI-algorithm for detecting intracranial LVOs. Viz LVO has demonstrated impressive performance for accurate identification and timely notification of proximal intracranial LVOs. Future endeavors to optimize detection of LVO in poor quality CTAs, despite anatomic variations such as tortuosity, and of the MCA-M2 are ongoing.
Abstract WMP17: Fully-Automated Ischemic Brain Infarct Volumetric Segmentation in Diffusion Weighted MR using Deep Learning
Authors: Chang Ken , Brown James , Beers Andrew , Rosen Bruce , Kalpathy-Cramer Jayashree , Ay Hakan
Published: January 2019

Introduction:
Brain imaging is a key step in the clinical evaluation of ischemic stroke, with Diffusion Weighted Magnetic Resonance (DWI) being a key imaging modality, as it allows for assessment of extent of acute ischemic brain injury. Manual delineation of stroke regions is expensive, time-consuming, and subject to inter-rater variability. In this study, we develop a deep learning approach for ischemic stroke volumetric segmentation in a large clinical dataset of 1,239 patients from the NIH-funded Heart-Brain Interactions in Human Acute Ischemic Stroke Study utilizing only DWI imaging.

Hypothesis:
Deep learning can be used to automatically calculate stroke volumes in high agreement with manual human expert segmentations.

Methods:
The patients were randomly divided into Training (n = 743), Validation (n=248), and Testing (n=248). We implemented the 3D U-Net neural network architecture. Additionally, we modified the 3D U-Net by incorporating incorporate state-of-the-art components that have improved neural network architectures for classification tasks, namely residual connections, inception modules, dense connections, and squeeze-and-excitation modules.

Results:
The best performing individual model was the Inception U-Net, which had a median dice similarity coefficient of 0.720 (0.011-0.920) within the Testing Set. In comparing manually and automatically derived infarct volumes, the Intraclass Correlation Coefficient was 0.974 (p<.0001) in the Testing Set.

Conclusions:
Our fully-automatic pipeline for stroke segmentation demonstrates the potential for deep learning-based tools to automate ischemic stroke volumetrics.