Combining Early Ischemic Change and Collateral Extent for Functional Outcomes After Endovascular Therapy: An Analysis From AcT Trial

BACKGROUND

Early ischemic change and collateral extent are colinear with ischemic core volume (ICV). We investigated the relationship between a combined score using the Alberta Stroke Program Early Computed Tomography Score and multiphase computed tomography angiography (mCTA) collateral extent, named mCTA-ACE score, on functional outcomes in endovascular therapy-treated patients.

METHODS

We performed a post hoc analysis of a subset of endovascular therapy-treated patients from the Alteplase Compared to Tenecteplase trial which was conducted between December 2019 and January 2022 at 22 centers across Canada. Ten-point mCTA collateral corresponding to M2 to M6 regions of the Alberta Stroke Program Early Computed Tomography Score grid was evaluated as 0 (poor), 1 (moderate), or 2 (normal) and additively combined with the 10-point Alberta Stroke Program Early Computed Tomography Score to produce a 20-point mCTA-ACE score. We investigated the association of mCTA-ACE score with modified Rankin Scale score ≤2 and return to prestroke level of function at 90 to 120 days using mixed-effects logistic regression. In the subset of patients who underwent baseline computed tomography perfusion imaging, we compared the mCTA-ACE score and ICV for outcome prediction.

RESULTS

Among 1577 intention-to-treat population in the trial, 368 (23%; 179 men; median age, 73 years) were included, with Alberta Stroke Program Early Computed Tomography Score, mCTA collateral, and combination of both (mCTA-ACE score: median [interquartile range], 8 [7-10], 9 [8-10], and 17 [16-19], respectively). The probability of modified Rankin scale score ≤2 and return to prestroke level of function increased for each 1-point increase in mCTA-ACE score (odds ratio, 1.16 [95% CI, 1.06-1.28] and 1.22 [95% CI, 1.06-1.40], respectively). Among 173 patients in whom computed tomography perfusion data was assessable, the mCTA-ACE score was inversely correlated with ICV (ρ=-0.46; P<0.01). The mCTA-ACE score was comparable to ICV to predict a modified Rankin scale score ≤2 and return to prestroke level of function (C statistics 0.71 versus 0.69 and 0.68 versus 0.64, respectively).

CONCLUSIONS

The mCTA-ACE score had a significant positive association with functional outcomes after endovascular therapy and had a similar predictive performance as ICV.

Timing of Spot Sign Appearance, Spot Sign Volume, and Leakage Rate among Phases of Multiphase CTA Predict Intracerebral Hemorrhage Growth

BACKGROUND AND PURPOSE

The presence of spot sign is associated with a high risk of hematoma growth. Our aim was to investigate the timing of the appearance, volume, and leakage rate of the spot sign for predicting hematoma growth in acute intracerebral hemorrhage using multiphase CTA.

MATERIALS AND METHODS

In this single-center retrospective study, multiphase CTA in 3 phases was performed in acute intracerebral hemorrhage (defined as intraparenchymal ± intraventricular hemorrhages). Phases of the spot sign first appearance, spot sign volumes (microliter), and leakage rates among phases (microliter/second) were measured. Associations between baseline clinical and imaging variables including spot sign volume parameters (volume and leakage rate divided by median) and hematoma growth (>6 mL) were investigated using regression models. Receiver operating characteristic analysis was used as appropriate.

RESULTS

Two hundred seventeen patients (131 men; median age, 70 years) were included. The spot sign was detected in 21.7%, 30.0%, and 29.0% in the first, second, and third phases, respectively, with median volumes of 19.7, 31.4, and 34.8 μl in these phases. Hematoma growth was seen in 44 patients (20.3%). By means of modeling, the following variables, namely the spot sign appearing in the first phase, first phase spot sign volume, spot sign appearing in the second or third phase, and spot sign positive and negative leakage rates, were associated with hematoma growth. Among patients with a spot sign, the absolute leakage rate accounting for both positive and negative leakage rates was also associated with hematoma growth (per 1-μl/s increase; OR, 1.26; 95% CI, 1.04-1.52). Other hematoma growth predictors were stroke history, baseline NIHSS score, onset-to-imaging time, and baseline hematoma volume (all P values < .05).

CONCLUSIONS

The timing of the appearance of the spot sign, volume, and leakage rate were all associated with hematoma growth. Development of automated software to generate these spot sign volumetric parameters would be an important next step to maximize the potential of temporal intracerebral hemorrhage imaging such as multiphase CTA for identifying those most at risk of hematoma growth.

Total intracranial hemorrhage volume measurement summating all compartments best in traumatic and nontraumatic intracranial bleeding

BACKGROUND AND PURPOSE

The ANNEXA-4 trial measured hemostatic efficacy of andexanet alfa in patients with major bleeding taking factor Xa inhibitors. A proportion of this was traumatic and nontraumatic intracranial bleeding. Different measurements were applied in the trial including volumetrics to assess for intracranial bleeding depending on the compartment involved. We aimed to determine the most reliable way to measure intracranial hemorrhage (ICrH) volume by comparing individual brain compartment and total ICrH volume.

METHODS

Thirty patients were randomly selected from the ANNEXA-4 database to assess measurement of ICrH volume by compartment and in total. Total and compartmental hemorrhage volumes were measured by five readers using Quantomo software. Each reader measured baseline hemorrhage volumes twice separated by 1 week. Twenty-eight different ANNEXA-4 subjects were also randomly selected to assess intra-rater reliability of total ICrH volume measurement change at baseline and 12-h follow up, performed by three readers twice to assess hemostatic efficacy categories used in ANNEXA-4.

RESULTS

Compartmental minimal detectable change percentages (MDC%) ranged between 9.72 and 224.13, with the greatest measurement error occurring in patients with a subdural hemorrhage. Total ICrH volume measurements had the lowest MDC%, which ranged between 6.57 and 33.52 depending on the reader.

CONCLUSION

Measurement of total ICrH volumes is more accurate than volume by compartment with less measurement error. Determination of hemostatic efficacy was consistent across readers, and within the same reader, as well as when compared to consensus read. Volumetric analysis of intracranial hemostatic efficacy is feasible and reliable when using total ICrH volumes.

Safety and efficacy of tenecteplase versus alteplase in stroke patients with carotid tandem lesions: Results from the AcT trial

BACKGROUND

Carotid tandem lesions ((TL) ⩾70% stenosis or occlusion) account for 15-20% of acute stroke with large vessel occlusion.

AIMS

We investigated the safety and efficacy of intravenous tenecteplase (0.25 mg/kg) versus intravenous alteplase (0.9 mg/kg) in patients with carotid TL.

METHODS

This is a substudy of the alteplase compared with the tenecteplase trial. Patients with ⩾70% stenosis of the extracranial internal carotid artery (ICA) and concomitant occlusion of the intracranial ICA, M1 or M2 segments of the middle cerebral artery on baseline computed tomography angiography (CTA) were included. Primary outcome was 90-day-modified Rankin Scale (mRS) 0-1. Secondary outcomes were mRS 0-2, mortality, and symptomatic ICH (sICH). Angiographic outcomes were successful recanalization (revised Arterial Occlusive Lesion (rAOL) 2b-3) on first and successful reperfusion (eTICI 2b-3) on final angiographic acquisitions. Multivariable mixed-effects logistic regression was performed.

RESULTS

Among 1577 alteplase versus tenecteplase randomized controlled trial (AcT) patients, 128 (18.8%) had carotid TL. Of these, 93 (72.7%) underwent intravenous thrombolysis plus endovascular thrombectomy (IVT + EVT), while 35 (27.3%) were treated with IVT alone. In the IVT + EVT group, tenecteplase was associated with higher odds of 90-day-mRS 0-1 (46.0% vs. 32.6%, adjusted OR (aOR) 3.21; 95% CI = 1.06-9.71) compared with alteplase. No statistically significant differences in rates of mRS 0-2 (aOR 1.53; 95% CI = 0.51-4.55), initial rAOL 2b-3 (16.3% vs. 28.6%), final eTICI 2b-3 (83.7% vs. 85.7%), and mortality (18.0% vs. 16.3%) were found. SICH only occurred in one patient. There were no differences in outcomes between thrombolytic agents in the IVT-only group.

CONCLUSION

In patients with carotid TL treated with EVT, intravenous tenecteplase may be associated with similar or better clinical outcomes, similar angiographic reperfusion rates, and safety outcomes as compared with alteplase.

Quality of Life After Intravenous Thrombolysis for Acute Ischemic Stroke: Results From the AcT Randomized Controlled Trial

BACKGROUND

Recent evidence from thrombolysis trials indicates the noninferiority of intravenous tenecteplase to intravenous alteplase with respect to good functional outcomes in patients with acute stroke. We examined whether the health-related quality of life (HRQOL) of patients with acute stroke differs by the type of thrombolysis treatment received. In addition, we examined the association between the modified Rankin Scale score 0 to 1 and HRQOL and patient-reported return to prebaseline stroke functioning at 90 days.

METHODS

Data were from all patients included in the AcT trial (Alteplase Compared to Tenecteplase), a pragmatic, registry-linked randomized trial comparing tenecteplase with alteplase. HRQOL at 90-day post-randomization was assessed using the 5-item EuroQOL questionnaire (EQ5D), which consists of 5 items and a visual analog scale (VAS). EQ5D index values were estimated from the EQ5D items using the time tradeoff approach based on Canadian norms. Tobit regression and quantile regression models were used to evaluate the adjusted effect of tenecteplase versus alteplase treatment on the EQ5D index values and VAS score, respectively. The association between return to prebaseline stroke functioning and the modified Rankin Scale score 0 to 1 and HRQOL was quantified using correlation coefficient (r) with 95% CI.

RESULTS

Of 1577 included in the intention-to-treat analysis patients, 1503 (95.3%) had complete data on the EQ5D. Of this, 769 (51.2%) were administered tenecteplase and 717 (47.7%) were female. The mean EQ5D VAS score and EQ5D index values were not significantly higher for those who received intravenous tenecteplase compared with those who received intravenous alteplase (P=0.10). Older age (P<0.01), more severe stroke assessed using the National Institutes of Health Stroke Scale (P<0.01), and longer stroke onset-to-needle time (P=0.004) were associated with lower EQ5D index and VAS scores. There was a strong association (r, 0.85 [95% CI, 0.81-0.89]) between patient-reported return to prebaseline functioning and modified Rankin Scale score 0 to 1 Similarly, there was a moderate association between return to prebaseline functioning and EQ5D index (r, 0.45 [95% CI, 0.40-0.49]) and EQ5D VAS scores (r, 0.42 [95% CI, 0.37-0.46]).

CONCLUSIONS

Although there is no differential effect of thrombolysis type on patient-reported global HRQOL and EQ 5D-5L index values in patients with acute stroke, sex- and age-related differences in HRQOL were noted in this study.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03889249.

Safety and Efficacy of Tenecteplase Compared With Alteplase in Patients With Large Vessel Occlusion Stroke: A Prespecified Secondary Analysis of the ACT Randomized Clinical Trial

Importance

It is unknown whether intravenous thrombolysis using tenecteplase is noninferior or preferable compared with alteplase for patients with acute ischemic stroke.

Objective

To examine the safety and efficacy of tenecteplase compared to alteplase among patients with large vessel occlusion (LVO) stroke.

Design, Setting, and Participants

This was a prespecified analysis of the Intravenous Tenecteplase Compared With Alteplase for Acute Ischaemic Stroke in Canada (ACT) randomized clinical trial that enrolled patients from 22 primary and comprehensive stroke centers across Canada between December 10, 2019, and January 25, 2022. Patients 18 years and older with a disabling ischemic stroke within 4.5 hours of symptom onset were randomly assigned (1:1) to either intravenous tenecteplase or alteplase and were monitored for up to 120 days. Patients with baseline intracranial internal carotid artery (ICA), M1-middle cerebral artery (MCA), M2-MCA, and basilar occlusions were included in this analysis. A total of 1600 patients were enrolled, and 23 withdrew consent.

Exposures

Intravenous tenecteplase (0.25 mg/kg) vs intravenous alteplase (0.9 mg/kg).

Main Outcomes and Measures

The primary outcome was the proportion of modified Rankin scale (mRS) score 0-1 at 90 days. Secondary outcomes were an mRS score from 0 to 2, mortality, and symptomatic intracerebral hemorrhage. Angiographic outcomes were successful reperfusion (extended Thrombolysis in Cerebral Infarction scale score 2b-3) on first and final angiographic acquisitions. Multivariable analyses (adjusting for age, sex, National Institute of Health Stroke Scale score, onset-to-needle time, and occlusion location) were carried out.

Results

Among 1577 patients, 520 (33.0%) had LVO (median [IQR] age, 74 [64-83] years; 283 [54.4%] women): 135 (26.0%) with ICA occlusion, 237 (45.6%) with M1-MCA, 117 (22.5%) with M2-MCA, and 31 (6.0%) with basilar occlusions. The primary outcome (mRS score 0-1) was achieved in 86 participants (32.7%) in the tenecteplase group vs 76 (29.6%) in the alteplase group. Rates of mRS 0-2 (129 [49.0%] vs 131 [51.0%]), symptomatic intracerebral hemorrhage (16 [6.1%] vs 11 [4.3%]), and mortality (19.9% vs 18.1%) were similar in the tenecteplase and alteplase groups, respectively. No difference was noted in successful reperfusion rates in the first (19 [9.2%] vs 21 [10.5%]) and final angiogram (174 [84.5%] vs 177 [88.9%]) among 405 patients who underwent thrombectomy.

Conclusions and Relevance

The findings in this study indicate that intravenous tenecteplase conferred similar reperfusion, safety, and functional outcomes compared to alteplase among patients with LVO.

First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9  GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36  GeV/c^{2}, rejecting cross sections above 9.2×10^{-48}  cm at the 90% confidence level.

Effect of Needle-To-Puncture Time on Reperfusion Outcome in Acute Ischemic Stroke

INTRODUCTION

The aim of the study was to investigate the impact of time interval between start of intravenous thrombolysis (IVT) to start of endovascular thrombectomy (EVT) on stroke outcomes.

METHODS

Data from the Quality Improvement and Clinical Research (QuICR) provincial stroke registry from Alberta, Canada, were used to identify stroke patients who received IVT and EVT from January 2015 to December 2019. We assessed the impact of the time interval between IVT bolus to EVT puncture (needle-to-puncture times [NPT]) on outcomes. Radiological outcomes included successful initial recanalization (revised Arterial Occlusive Lesion 2b-3), successful initial and final reperfusion (modified thrombolysis in cerebral infarction 2b-3). Clinical outcomes were 90-day modified Rankin Scale (mRS) and mortality.

RESULTS

Of the 680 patients, 233 patients (median age: 73, 41% females) received IVT + EVT. Median NPT was 38 min (IQR, 24-60). Arrival during working hours was independently associated with shorter NPT (p < 0.001). Successful initial recanalization and initial and final reperfusion were observed in 12%, 10%, and 83% of patients, respectively. NPT was not associated with initial successful recanalization (OR 0.97 for every 10-min increase of NPT, 95% CI: 0.91-1.04), initial successful reperfusion (OR 1.01, 95% CI: 0.96-1.07), or final successful reperfusion (OR: 1.03, 95% CI: 0.97-1.08). Every 10-min delay in NPT was associated with lower odds of functional independence at 90 days (mRS ≤2; OR: 0.93; 95% CI, 0.88-0.97). Patients with shorter NPT (≤38 min) had lower 90-day mRS scores (median 1 vs. 3; OR: 0.54 [0.31-0.91]) and had lower mortality (6.1% vs. 21.2%; OR, 0.23 [0.10-0.57]) than the longer NPT group.

CONCLUSION

Shorter NPT did not impact reperfusion outcomes but was associated with better clinical outcome.

Abstract WP113: Feasibility Of Non-invasive Brain Temperature Measurement In Acute Ischemic Stroke: A Comparison Study Of MR Thermometry Vs. Zero-Heat-Flux Sensors

Introduction: Brain-selective hypothermia is a promising neuroprotectant in acute ischemic stroke. However, a non-invasive bedside method to monitor brain temperature during cooling is lacking. We tested the feasibility and accuracy of measuring brain temperature non-invasively using sensors designed to monitor core body temperature.

Methods: In this prospective single-center study, 20 patients with large or medium vessel occlusion strokes were enrolled. Patients underwent a 3T MR spectroscopy imaging (MRSI, the reference standard) and zero heat flux (ZHF) core temperature sensor measurements (3M TM Bair Hugger TM ) within 12-72 hours from admission. Two ZHF sensors were placed on each side of the forehead on the side of stroke and contralateral side and the temperatures were checked before and after MRSI. A 2x2x2 cm voxel was centered on the infarct and matching contralateral location using diffusion weighted imaging. Brain temperature on MRSI was calculated using the relative chemical shifts of water and N-acetyl aspartate. Temperature measurements of the ZHF sensors were compared to MRSI measurements.

Results: The brain temperature of stroke and contralateral sides were similar using MRSI or using ZHF sensors when each modality was compared to itself by hemisphere (all p>0.05). However, there was a significant difference for the ipsilateral side: median (SD) temperatures using MRSI was 36.0°C (1.8) vs 36.8°C (0.5) for sensor measurement. Bland-Altman plots showed that 95% of the observations fell within upper and lower limits of agreement of -2.1 to +3.7°C while 61% of observations fell within an agreement limit of +/- 1°C. There was an indication of an overall higher temperature measurements using the ZHF sensors compared to MRSI (Figure 1).

Conclusions: More studies are needed to validate the use of ZHF thermometry in ischemic stroke including studies implementing hypothermia.

Figure 1. Boxplot of stroke side MRSI compared to zero-heat-flux sensors.

Abstract WP126: Predictors Of Intracranial Hemorrhage Volume Expansion In Patients Receiving Factor Xa Inhibitors In The Annexa-4 Trial

Introduction: Andexanet, a specific reversal agent for FXa inhibitors, showed an effective hemostasis in 82% of patients with major bleeding in the ANNEXA-4 trial. However, little is known about the predictors associated with hematoma expansion in patients with FXa inhibitor-associated intracranial hemorrhage (ICrH) receiving andexanet.

Methods: ANNEXA-4 was a prospective, single-arm, open-label study of andexanet in patients with acute major bleeding within 18h after taking a FXa inhibitor. Hematoma volumes at baseline and 12h after andexanet treatment were measured utilizing a computerized-assisted volumetric method. Univariate and multivariate logistic regression analyses of baseline clinical and non-clinical parameters were performed to identify factors predictive of different volumes of hematoma expansion.

Results: A total of 305 patients with both baseline and follow-up imaging were included (mean age 80 years; 60.2% with intracerebral hemorrhage; 55.4% taking apixaban; 32.5% taking rivaroxaban). Overall median baseline hematoma volume was 10.4 mls (IQR 2.7-28.1) and time from symptom onset to baseline CT was 3.3h (1.5-6.8). Mean baseline anti-FXa activity levels were 148 ng/mL (SD 107.5). In follow up scans, 48 cases (15.7%) showed evidence of ICrH expansion ≥6 mls. Utilizing a four category ICrH Expansion Scale as the dependent variable, ordinal logistic regression identified Glasgow Coma Scale (GCS) score (OR 0.79; 95% CI 0.64-0.97), baseline ICrH volume (OR 1.02; 95% CI 1.01-1.04) and time from symptom onset to CT (OR 0.73 (0.53-0.99) as significant predictors of ICrH expansion. Baseline anti-FXA activity (OR 1.54; 95% CI 0.95-2.51; p value 0.08) and multiple compartment ICrH (OR 2.32; 95% CI 0.98-5.51; p value 0.06) showed trend as predictors of ICrH expansion. ICrH expansion dichotomized by ≥6 mls or <6 mls as dependent variable, identified similar predictors of ICrH expansion.

Conclusions: Shorter time from onset of symptoms to CT, lower GCS score and larger hematoma volumes at presentation increased the probability of ICrH expansion in FXa-associated ICrH treated with andexanet. These findings can inform the eligibility criteria of clinical trials targeting hemostatic efficacy in patients with FXa-associated ICrH.

Non-invasive Brain Temperature Measurement in Acute Ischemic Stroke

Selective therapeutic hypothermia in the setting of mechanical thrombectomy (MT) is promising to further improve the outcomes of large vessel occlusion stroke. A significant limitation in applying hypothermia in this setting is the lack of real-time non-invasive brain temperature monitoring mechanism. Non-invasive brain temperature monitoring would provide important information regarding the brain temperature changes during cooling, and the factors that might influence any fluctuations. This review aims to provide appraisal of brain temperature changes during stroke, and the currently available non-invasive modalities of brain temperature measurement that have been developed and tested over the past 20 years. We cover modalities including magnetic resonance spectroscopy imaging (MRSI), radiometric thermometry, and microwave radiometry, and the evidence for their accuracy from human and animal studies. We also evaluate the feasibility of using these modalities in the acute stroke setting and potential ways for incorporating brain temperature monitoring in the stroke workflow.

Prediction of 90 day home time among patients with low baseline ASPECTS undergoing endovascular thrombectomy: results from Alberta's Provincial Stroke Registry (QuICR)

BACKGROUND

The benefit of endovascular thrombectomy (EVT) in stroke patients with a low baseline Alberta Stroke Program Early CT Score (ASPECTS, ≤5) is uncertain. We aim to use random forest regression modeling to predict 90 day home time in patients with low ASPECTS.

METHODS

We used the Quality Improvement and Clinical Research (QuICR) provincial stroke registry and administrative data from southern Alberta to identify patients who underwent EVT in our center from July 2015 to November 2020. Baseline ASPECTS on non-contrast CT and CT angiography data were scored by a two physician consensus. The primary outcome was the predicted 90 day home time (the number of nights a patient is back at their premorbid living situation without an increase in level of care within 90 days of the stroke) using random forests regression. Estimates were generated using 200 bootstrapped datasets. Covariate contribution to home time was determined using partial dependence plots.

RESULTS

Of 657 EVT patients, 85 (12.9%) had baseline ASPECTS ≤5 (mean age 70.9 years, 44.7% women, 93.9% good-moderate collaterals, 60% M1-middle cerebral artery occlusion). Using partial dependence estimates, mean predicted home times were similar in the low ASPECTS (44.3 days) versus higher ASPECTS (43.1) groups. Factors predicting lower 90 day home time in this population were diabetes mellitus (-8.8 days), hypertension (-5.7 days), and atrial fibrillation (-3.6 days). There was no meaningful difference in predicted 90 day home time by sex, baseline National Institutes of Health Stroke Severity Scale score, occlusion site, tandem lesion, collateral grade or thrombolysis.

CONCLUSIONS

Patients with low ASPECTS who are selected for EVT using demographic and clinical profiles similar to higher ASPECTS patients achieved comparable outcomes.

Prediction of 90 day home time among patients with low baseline ASPECTS undergoing endovascular thrombectomy: results from Alberta's Provincial Stroke Registry (QuICR)

BACKGROUND

The benefit of endovascular thrombectomy (EVT) in stroke patients with a low baseline Alberta Stroke Program Early CT Score (ASPECTS, ≤5) is uncertain. We aim to use random forest regression modeling to predict 90 day home time in patients with low ASPECTS.

METHODS

We used the Quality Improvement and Clinical Research (QuICR) provincial stroke registry and administrative data from southern Alberta to identify patients who underwent EVT in our center from July 2015 to November 2020. Baseline ASPECTS on non-contrast CT and CT angiography data were scored by a two physician consensus. The primary outcome was the predicted 90 day home time (the number of nights a patient is back at their premorbid living situation without an increase in level of care within 90 days of the stroke) using random forests regression. Estimates were generated using 200 bootstrapped datasets. Covariate contribution to home time was determined using partial dependence plots.

RESULTS

Of 657 EVT patients, 85 (12.9%) had baseline ASPECTS ≤5 (mean age 70.9 years, 44.7% women, 93.9% good-moderate collaterals, 60% M1-middle cerebral artery occlusion). Using partial dependence estimates, mean predicted home times were similar in the low ASPECTS (44.3 days) versus higher ASPECTS (43.1) groups. Factors predicting lower 90 day home time in this population were diabetes mellitus (-8.8 days), hypertension (-5.7 days), and atrial fibrillation (-3.6 days). There was no meaningful difference in predicted 90 day home time by sex, baseline National Institutes of Health Stroke Severity Scale score, occlusion site, tandem lesion, collateral grade or thrombolysis.

CONCLUSIONS

Patients with low ASPECTS who are selected for EVT using demographic and clinical profiles similar to higher ASPECTS patients achieved comparable outcomes.

Intravenous tenecteplase compared with alteplase for acute ischaemic stroke in Canada (AcT): a pragmatic, multicentre, open-label, registry-linked, randomised, controlled, non-inferiority trial

BACKGROUND

Intravenous thrombolysis with alteplase bolus followed by infusion is a global standard of care for patients with acute ischaemic stroke. We aimed to determine whether tenecteplase given as a single bolus might increase reperfusion compared with this standard of care.

METHODS

In this multicentre, open-label, parallel-group, registry-linked, randomised, controlled trial (AcT), patients were enrolled from 22 primary and comprehensive stroke centres across Canada. Patients were eligible for inclusion if they were aged 18 years or older, with a diagnosis of ischaemic stroke causing disabling neurological deficit, presenting within 4·5 h of symptom onset, and eligible for thrombolysis per Canadian guidelines. Eligible patients were randomly assigned (1:1), using a previously validated minimal sufficient balance algorithm to balance allocation by site and a secure real-time web-based server, to either intravenous tenecteplase (0·25 mg/kg to a maximum of 25 mg) or alteplase (0·9 mg/kg to a maximum of 90mg; 0·09 mg/kg as a bolus and then a 60 min infusion of the remaining 0·81 mg/kg). The primary outcome was the proportion of patients who had a modified Rankin Scale (mRS) score of 0-1 at 90-120 days after treatment, assessed via blinded review in the intention-to-treat (ITT) population (ie, all patients randomly assigned to treatment who did not withdraw consent). Non-inferiority was met if the lower 95% CI of the difference in the proportion of patients who met the primary outcome between the tenecteplase and alteplase groups was more than -5%. Safety was assessed in all patients who received any of either thrombolytic agent and who were reported as treated. The trial is registered with ClinicalTrials.gov, NCT03889249, and is closed to accrual.

FINDINGS

Between Dec 10, 2019, and Jan 25, 2022, 1600 patients were enrolled and randomly assigned to tenecteplase (n=816) or alteplase (n=784), of whom 1577 were included in the ITT population (n=806 tenecteplase; n=771 alteplase). The median age was 74 years (IQR 63-83), 755 (47·9%) of 1577 patients were female and 822 (52·1%) were male. As of data cutoff (Jan 21, 2022), 296 (36·9%) of 802 patients in the tenecteplase group and 266 (34·8%) of 765 in the alteplase group had an mRS score of 0-1 at 90-120 days (unadjusted risk difference 2·1% [95% CI - 2·6 to 6·9], meeting the prespecified non-inferiority threshold). In safety analyses, 27 (3·4%) of 800 patients in the tenecteplase group and 24 (3·2%) of 763 in the alteplase group had 24 h symptomatic intracerebral haemorrhage and 122 (15·3%) of 796 and 117 (15·4%) of 763 died within 90 days of starting treatment INTERPRETATION: Intravenous tenecteplase (0·25 mg/kg) is a reasonable alternative to alteplase for all patients presenting with acute ischaemic stroke who meet standard criteria for thrombolysis.

FUNDING

Canadian Institutes of Health Research, Alberta Strategy for Patient Oriented Research Support Unit.

AB1120 PSYCHOLOGICAL ASSESSMENT IN PATIENTS WITH CHRONIC RHEUMATIC, SYSTEMIC AUTOIMMUNE, OR AUTOINFLAMMATORY DISEASES PRESENTED WITH COVID-19: THE MentCOVRMD STUDY

Background

The COVID-19 pandemic has raised concerns about its psychological effects. Sleep disturbances, anxiety and/or depressive symptoms, post-traumatic stress symptoms have been reported in general population. Patients with chronic rheumatism, systemic autoimmune disease or auto-inflammatory disease, due to immunosuppression, are at risk of severe forms of infection. Currently, there is little information on psychological impact of the pandemic on the mental health of these more vulnerable patients.

Objectives

To compare psychological assessment between patients with chronic rheumatic, autoimmune and/or autoinflammatory diseases who presented with COVID-19 infection between March and September 2020, first wave of French pandemic, and patients with same diseases who did not presented with infection to date.

Methods

The MentCOVRMD study was a multicenter descriptive study. Cases were patients with chronic rheumatic, autoimmune and/or autoinflammatory diseases from the French RMD cohort who presented COVID-19 infection between March and September 2020. Controls were patients with same diseases who did not develop infection. The study is registered in Clinical Trials under number 2020-A02058-31.

For participants, following criteria were collected: demographics (age, gender, smoking status); psychological assessment questionnaires: Insomnia Severity Index (ISI); Post-traumatic stress disorder (PTSD) checklist; Patient Health Questionnaire (PHQ9) Depression; Generalized Anxiety Disorder (GAD7) Anxiety; Patient Health Questionnaire-15 (PHQ-15) and Somatic Symptom Disorder (SSD)-12.

Results

Between February and December 2021, 60 cases (46 (76.7%) women), median age 52.0 (39.0; 63.0) were included, of which 15 (25%) had been hospitalized during infection, and 169 controls (148 (87.6%) women), median age of 52.0 (38.0; 63.0). There were more smokers in the group of cases 12 (20%) than controls 14 (9.1%) (p=0.028) as well as more cases on ARA2 treatment (8 (13.3%)) than controls (7 (4.5%)) (p=0.035) with no statistically significant difference in others comorbidities or treatments.

There was no statistically difference concerning the ISI scores between cases (11.83 ± 7.31) of which 60% had sleep disorders and controls (11.64 ± 6.82) of which 70.4% had sleep disorders. There was no statistically significant difference in PTSD scores of 15.5 (5.0 to 28.0) for cases and 18.0 (8.0 to 35.0) for controls, of which respectively 12 (20%) had values indicating possible PTSD for cases and 50 (29.6%) for controls. There was no statistically significant difference in PHQ-9 scores (5.5 (1.5 to 11.0)) of which 50% had depressive symptoms and controls (6.0 (2.0 to 11.0)) of which 54.5% had symptoms. There was no statistically significant difference in GAD-7 scores (3.5 (0.0 to 8.0)) of which 40% had anxiety symptoms and controls (4.0 (0.0 to 8.0)) of which 43.2% had symptoms. There was no statistically significant difference in PHQ-15 scores (11.4 ± 6.7), 85% of whom reported presence of symptoms, and controls (10.9 ± 6.2), 82.3% of whom reported symptoms. There was no statistically significant difference in SSD scores between cases (17.7 ± 10.9) and controls (18.4 ± 10.9).

There was a statistically significant difference in reported VAS scores of pain related to inflammatory rheumatism in cases with a median of 4.5 (3.0 to 6. 0) compared to controls with a median of 4.0 (1.0 to 6.0) (p=0.011).

There was no statistically significant difference in any of the psychological assessment scores between the inpatient and outpatient COVID cases.

Conclusion

There was no statistically significant difference between COVID cases and controls in the evaluation of these psychological parameters. Prevalence of all these variables were high in the whole study population, testifying to the need to manage these psychological aspects for patients with chronic rheumatisms, autoimmune and/or autoinflammatory diseases.

Disclosure of Interests

None declared

Abstract WP167: Machine Learning Modelling To Predict 90 Day Home Time In Patients Undergoing Endovascular Thrombectomy

Background: 90-day home-time, the number of days a patient is back at their premorbid living situation without an increase in level of care in the first 90 days post stroke, is routinely collected in administrative data. We evaluated the prediction of 90-day home-time using machine learning modelling in patients undergoing endovascular treatment (EVT).

Methods: We used the QuICR provincial stroke registry and administrative data from Southern Alberta from Jan 2015-Dec 2019 to identify patients who underwent EVT. Imaging data were scored by 2-physician consensus. The primary outcome was 90 day home-time, which has a highly non-normal distribution with excess zero’s. We modelled using generalized boosting machine model with Gaussian distribution. Contribution of different covariates to hometime was determined using partial dependence plots.

Results: We identified 659 EVT patients from Jan 2015 to Dec 2019 treated in Calgary, Alberta. Overall,median predicted 90d home-time was 41days (IQR 5.5 to 77.8) with good model accuracy (Root mean square error 6.96). Holding other covariates constant, factors predicting lower 90d-hometime were diabetes mellitus(-14.1d), hypertension (-7d), low baseline ASPECTS (≤5) (-5.6d) and symptomatic intracerebral hemorrhage (sICH) on follow up scan (-13.8d). There was a consistent improvement in the predicted home-time over the last 5 years. There was no meaningful difference in predicted 90d-home-time by age, baseline NIHSS, sex, atrial fibrillation, occlusion site, tandem occlusion, thrombolysis, or successful reperfusion (Figure 1)

Conclusions: Predicting 90-d hometime using boosting machine learning modelling is useful to assess complex relationships between predictors and home-time. Hypertension, diabetes, low ASPECTS and sICH were predictors of lower 90-d home-time in this registry.

Abstract WP164: Prediction Of 90 Day Home Time Among Patients With Low Baseline Aspects Score Undergoing Endovascular Thrombectomy

Background: The outcome in stroke patients with ASPECTS of ≤5 who undergo Endovascular Thrombectomy(EVT) in Large Vessel Occlusion (LVO) is uncertain. We used machine learning models to predict 90-day home-time in these patients.

Methods: We used the QuICR provincial stroke registry and administrative data from Southern Alberta to identify patients who underwent EVT from Jan 2015-Dec 2019. Imaging data were scored by 2-physician consensus. The primary outcome was the predicted 90-day home-time(number of days a patient is back at their premorbid living situation without an increase in level of care within 90 days of the stroke) using generalized boosting machine model with Gaussian distribution. Covariate contribution to hometime was determined using partial dependence plots.

Results: Of 659 EVT patients, 82(12%) had baseline ASPECTS ≤5(mean age 69.8y, 44.6% females, 93% good-moderate collaterals, M1 occlusion(64.1%). Overall, patients with low ASPECTS had lower median predicted home-time by 2.8d. Holding other covariates constant, factors predicting lower 90d-home-time were diabetes mellitus(-14d), hypertension(-7d), and symptomatic intracerebral hemorrhage (sICH) on follow up scan(-14d). Home-time decreased with increasing age in both low and non-low ASPECTS groups, but the difference was larger in older age groups (Figure). There was no meaningful difference in predicted 90d-home-time by sex, atrial fibrillation, baseline NIHSS, occlusion site, tandem lesion, thrombolysis, or successful reperfusion.

Conclusions: Among patients with low ASPECTS who underwent EVT, hypertension, diabetes and sICH predicted lower 90-d home-time. .

The life cycle-dependent transcriptional profile of the obligate intracellular amoeba symbiont Amoebophilus asiaticus

Free-living amoebae often harbor obligate intracellular bacterial symbionts. Amoebophilus (A.) asiaticus is a representative of a lineage of amoeba symbionts in the phylum Bacteroidota. Here, we analyse the transcriptome of A. asiaticus strain 5a2 at four time points during its infection cycle and replication within the Acanthamoeba host using RNA sequencing. Our results reveal a dynamic transcriptional landscape throughout different A. asiaticus life cycle stages. Many intracellular bacteria and pathogens utilize eukaryotic-like proteins (ELPs) for host cell interaction and the A. asiaticus 5a2 genome shows a particularly high abundance of ELPs. We show the expression of all genes encoding ELPs and found many ELPs to be differentially expressed. At the replicative stage of A. asiaticus, ankyrin repeat proteins and tetratricopeptide/Sel1-like repeat proteins were upregulated. At the later time points, high expression levels of a type 6 secretion system that likely prepares for a new infection cycle after lysing its host, were found. This study reveals comprehensive insights into the intracellular lifestyle of A. asiaticus and highlights candidate genes for host cell interaction. The results from this study have implications for other intracellular bacteria such as other amoeba-associated bacteria and the arthropod symbionts Cardinium forming the sister lineage of A. asiaticus.

Accuracy of registration techniques and vascular imaging modalities in fusion imaging for aortic endovascular interventions: a phantom study

Background

This study aimed to assess the error of different registration techniques and imaging modalities for fusion imaging of the aorta in a standardized setting using a anthropomorphic body phantom.

Materials and methods

A phantom with the 3D printed vasculature of a patient suffering from an infrarenal aortic aneurysm was constructed. Pulsatile flow was generated via an external pump. CTA/MRA of the phantom was performed, and a virtual 3D vascular model was computed. Subsequently, fusion imaging was performed employing 3D-3D and 2D-3D registration techniques. Accuracy of the registration was evaluated from 7 right/left anterior oblique c-arm angulations using the agreement of centerlines and landmarks between the phantom vessels and the virtual 3D virtual vascular model. Differences between imaging modalities were assessed in a head-to-head comparison based on centerline deviation. Statistics included the comparison of means ± standard deviations, student’s t-test, Bland-Altman analysis, and intraclass correlation coefficient for intra- and inter-reader analysis.

Results

3D-3D registration was superior to 2D-3D registration, with the highest mean centerline deviation being 1.67 ± 0.24 mm compared to 4.47 ± 0.92 mm. The highest absolute deviation was 3.25 mm for 3D-3D and 6.25 mm for 2D-3D registration. Differences for all angulations between registration techniques reached statistical significance. A decrease in registration accuracy was observed for c-arm angulations beyond 30° right anterior oblique/left anterior oblique. All landmarks (100%) were correctly positioned using 3D-3D registration compared to 81% using 2D-3D registration. Differences in accuracy between CT and MRI were acceptably small. Intra- and inter-reader reliability was excellent.

Conclusion

In the realm of registration techniques, the 3D-3D method proved more accurate than did the 2D-3D method. Based on our data, the use of 2D-3D registration for interventions with high registration quality requirements (e.g., fenestrated aortic repair procedures) cannot be fully recommended. Regarding imaging modalities, CTA and MRA can be used equivalently.

MRI Diffusion-Weighted Imaging to Measure Infarct Volume: Assessment of Manual Segmentation Variability

BACKGROUND AND PURPOSE

Manual segmentation of infarct volume on follow-up MRI diffusion-weighted imaging (MRI-DWI) is considered the gold standard but is prone to rater variability. We assess the variability of manual segmentations of MRI-DWI infarct volume.

METHODS

Consecutive patients (May 2018 to May 2019) with the anterior circulation stroke and endovascularly treated were enrolled. All patients underwent 24- to 32-hour follow-up MRI. Three users manually segmented DWI infarct volumes slice by slice twice. The reference standard of DWI infarct volume was generated by the STAPLE algorithm. Intra- and interrater reliability was evaluated using the intraclass correlation coefficient (ICC) by comparing manual segmentations with the reference standard. Spatial measurements were evaluated using metrics of the Dice similarity coefficient (DSC). Volumetric measurements were compared using the lesion volume.

RESULTS

The dataset consisted of 44 patients, mean (SD) age was 70.1 years (±10.3), 43% were women, and median baseline NIHSS score was 16. Among three users, the mean DSC for MRI-DWI infarct volume segmentations ranged from 80.6% ± 11.7% to 88.6% ± 7.5%, and the mean absolute volume difference was 2.8 ± 6.8 to 13.0 ± 14.0 ml. Interrater ICC among the users for DSC and infarct volume was .86 (95% confidence interval [95% CI]: .78-.91) and .997 (95% CI: .995-.998). Intrarater ICC for the three users was .83 (95% CI: .69-.93), .84 (95% CI: .72-.91), and .80 (95% CI: .64-.89) for DSC, and .99 (95% CI: .987-.996), .991 (95% CI: .983-.995), and .996 (95% CI: .993-.998) for infarct volume.

CONCLUSIONS

Manual segmentation of infarct volume on follow-up MRI-DWI shows excellent agreement and good spatial overlap with the reference standard, suggesting its usefulness for measuring infarct volume on 24- to 32-hour MRI-DWI.

The neural correlates of the visual consciousness in schizophrenia: an fMRI study

In the current literature, two distinct and opposite models are suggested to explain the consciousness disorders in schizophrenia. The first one suggests that consciousness disorders rely on a low-level processing deficit, when the second model suggests that consciousness disorders rely on disruption in the ability to consciously access information, with preserved unconscious processing. The current study aims to understand the mechanisms associated with visual consciousness disorder in order to pave the road that will settle the debate regarding these hypotheses. During a functional magnetic resonance imaging session, 19 healthy participants (HC) and 15 patients with schizophrenia (SCZ) performed a visual detection task to compare the neural substrates associated with the conscious access to the visual inputs. The visual detection threshold was significantly higher in SCZ than in HC [t(32) = 3.37, p = 0.002]. Whole-brain ANOVA demonstrated that around the visual detection threshold patients with SCZ failed to activate a large network of brain areas compared to HC. (1) During conscious vision, HC engaged more the left cuneus and the right occipital cortex than patients with SCZ, (2) during unconscious vision, HC engaged a large network that patients with SCZ failed to activate, and finally, (3) during the access to consciousness process, patients with SCZ failed to activate the anterior cingulate cortex. These results suggest that the consciousness disorders in schizophrenia rely on specific dysfunctions depending on the consciousness stage. The disorders of the conscious vision are associated with dysfunction of occipital areas while the ones associated with unconscious vision rely on a large widespread network. Finally, the conscious access to the visual inputs is impaired by a dysfunction of the anterior cingulate cortex. The current study suggests that none of the two suggested models can explain consciousness disorders in schizophrenia. We suggest that there is an alternative model supporting that the conscious access to visual inputs is due to a disengagement of the supragenual anterior cingulate during the unconscious processing of the visual inputs associated with a sensory deficit.

Thrombus Migration and Fragmentation After Intravenous Alteplase Treatment: The INTERRSeCT Study

BACKGROUND AND PURPOSE

There is interest in what happens over time to the thrombus after intravenous alteplase. We study the effect of alteplase on thrombus structure and its impact on clinical outcome in patients with acute stroke.

METHODS

Intravenous alteplase treated stroke patients with intracranial internal carotid artery or middle cerebral artery occlusion identified on baseline computed tomography angiography and with follow-up vascular imaging (computed tomography angiography or first run of angiography before endovascular therapy) were enrolled from INTERRSeCT study (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography). Thrombus movement after intravenous alteplase was classified into complete recanalization, thrombus migration, thrombus fragmentation, and no change. Thrombus migration was diagnosed when occlusion site moved distally and graded according to degrees of thrombus movement (grade 0-3). Thrombus fragmentation was diagnosed when a new distal occlusion in addition to the primary occlusion was identified on follow-up imaging. The association between thrombus movement and clinical outcome was also evaluated.

RESULTS

Among 427 patients in this study, thrombus movement was seen in 54% with a median time of 123 minutes from alteplase administration to follow-up imaging, and sub-classified as marked (thrombus migration grade 2-3 + complete recanalization; 27%) and mild to moderate thrombus movement (thrombus fragmentation + thrombus migration grade 0-1; 27%). In patients with proximal M1/internal carotid artery occlusion, marked thrombus movement was associated with a higher rate of good outcome (90-day modified Rankin Scale, 0-2) compared with mild to moderate movement (52% versus 27%; adjusted odds ratio, 5.64 [95% CI, 1.72-20.10]). No difference was seen in outcomes between mild to moderate thrombus movement and no change. In M1 distal/M2 occlusion, marked thrombus movement was associated with improved 90-day good outcome compared with no change (70% versus 56%; adjusted odds ratio, 2.54 [95% CI, 1.21-5.51]).

CONCLUSIONS

Early thrombus movement is common after intravenous alteplase. Marked thrombus migration leads to good clinical outcomes. Thrombus dynamics over time should be further evaluated in clinical trials of acute reperfusion therapy.

Schizophrénie et violence : la nécessité de considérer différents sous-groupes

Il est aujourd’hui clairement établi que les patients souffrant de schizophrénie présente un risque plus élevé de violence que la population générale. Différents facteurs de risque de violence ont été mis en évidence chez ces patients, tels que l’impulsivité, le trouble de personnalité antisociale, les comorbidités addictives. Néanmoins, les études ayant tenté d’identifier le risque de violence des patients schizophrènes ont abouti à des résultats variables. L’hétérogénéité des gestes de violence commis, ainsi que la variabilité des profils de ces patients contribuent certainement à la divergence de ces résultats. Par ailleurs, différents auteurs ont montré que les patients présentant un délire d’identification des personnes constituaient une sous-catégorie de patients à risque de comportements violents, devenant agressifs et violents du fait du thème de leur délire. Cependant, aucune étude n’a exploré l’association entre délire d’identification et type de geste violent. Nous nous sommes donc intéressés à l’étude des caractéristiques cliniques de patients schizophrènes ayant commis des gestes de violence, à partir d’une étude descriptive réalisée sur une population de patients schizophrènes détenus. Nous avons évalué l’intensité des symptômes grâce à la Positive and Negative Symptom Scale (PANSS), la coexistence d’un trouble de personnalité antisociale et les comorbidités addictives grâce au Mini International Neuropsychiatric Interview (MINI). Le niveau d’impulsivité et les comportements violents ont été estimés par la Baratt Impulsivity Scale (BIS) et la MacArthur Community Violence Interview. Enfin, l’existence de troubles de la familiarité, tels que ceux qui caractérisent les délires d’identification des personnes, a été systématiquement recherchée. Notre objectif est, d’une part, d’évaluer de manière systématique les troubles de familiarité des patients schizophrènes, et leur association avec les comportements violents, et d’autre part, d’objectiver l’hétérogénéité des profils des patients schizophrènes ayant commis des gestes de violence.

Abstract 77: Ongoing Leakage Revealed by Second Phase Spot Sign Volume Expansion in Multi-Phase Computed Tomography Angiography Strongly Predicts Intracranial Hemorrhage Growth

Background: CTA spot sign is a predictor of intracerebral hemorrhage (ICH) expansion. This sign can fluctuate in appearance, volume, and timing. Multiphase CTA (mCTA) can identify spot sign through 3 time-resolved images. We sought to identify a novel predictor of follow up total hematoma expansion using mCTA.

Methods: This cohort study included patients with ICH between 2012-2019. Quantomo software was used to measure total hematoma volume (ml) from baseline CT & follow-up CT/MRI blinded to spot sign in 3 mCTA phases. Spot sign expansion was calculated by subtracting 1 st phase spot sign volume from 2 nd phase spot sign volume measured in microliters.

Results: 199 patients [63% male, mean age 69 years, median NIHSS 11, IQR 6-20] were included. Median baseline ICH volume was 16.1 ml (IQR 5-29.9 ml). Amongst all three mCTA phases, spot sign was best detected on the 2nd phase (23% vs 17.5% 1 st phase vs 22% 3 rd phase). In multivariable regression, spot sign expansion was significantly associated with follow up total hematoma expansion (OR: 1.03 per microliter of spot sign expansion, p=0.01). Figure 1 shows the predicted total hematoma expansion by spot sign expansion. mCTA spot sign had a higher sensitivity for predicting total hematoma volume expansion than single-phase CTA (reported in meta-analysis of 14 studies), 86% vs 53%, respectively, while both having similar specificity, 87% vs 88%, respectively.

Conclusion: Spot sign expansion on mCTA is a novel predictor of total hematoma expansion and could be used to select patients for immediate therapeutic intervention in future clinical trials. Using mCTA improves sensitivity while preserving specificity over single-phase CTA.

Semi-automatic measurement of intracranial hemorrhage growth on non-contrast CT

BACKGROUND

Manual segmentations of intracranial hemorrhage on non-contrast CT images are the gold-standard in measuring hematoma growth but are prone to rater variability.

AIMS

We demonstrate that a convex optimization-based interactive segmentation approach can accurately and reliably measure intracranial hemorrhage growth.

METHODS

Baseline and 16-h follow-up head non-contrast CT images of 46 subjects presenting with intracranial hemorrhage were selected randomly from the ANNEXA-4 trial imaging database. Three users semi-automatically segmented intracranial hemorrhage to measure hematoma volume for each timepoint using our proposed method. Segmentation accuracy was quantitatively evaluated compared to manual segmentations by using Dice similarity coefficient, Pearson correlation, and Bland-Altman analysis. Intra- and inter-rater reliability of the Dice similarity coefficient and intracranial hemorrhage volumes and volume change were assessed by the intraclass correlation coefficient and minimum detectable change.

RESULTS

Among the three users, the mean Dice similarity coefficient, Pearson correlation, and mean difference ranged from 76.79% to 79.76%, 0.970 to 0.980 (p < 0.001), and -1.5 to -0.4 ml, respectively, for all intracranial hemorrhage segmentations. Inter-rater intraclass correlation coefficients between the three users for Dice similarity coefficient and intracranial hemorrhage volume were 0.846 and 0.962, respectively, and the corresponding minimum detectable change was 2.51 ml. Inter-rater intraclass correlation coefficient for intracranial hemorrhage volume change ranged from 0.915 to 0.958 for each user compared to manual measurements, resulting in an minimum detectable change range of 2.14 to 4.26 ml.

CONCLUSIONS

We spatially and volumetrically validate a novel interactive segmentation method for delineating intracranial hemorrhage on head non-contrast CT images. Good spatial overlap, excellent volume correlation, and good repeatability suggest its usefulness for measuring intracranial hemorrhage volume and volume change on non-contrast CT images.

Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5  GeV/c^{2} using 1.4×10^{4}  kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

Abstract 82: Thrombus Migration is a Common Phenomenon With IV TPA and May Have Negative Effects on Outcome When TPA Treatment is Given Before Endovascular Thrombectomy in Proximal Occlusions

Introduction: There is interest in understanding thrombus dynamics from IV TPA prior to endovascular thrombectomy (EVT) given the possible dichotomy amongst sites of occlusion for IV TPA benefit/harm. Kaesmacher et al reported beneficial 5+% rates of early TICI > 2a reperfusion in distal M1 or M2 MCA occlusions with IV TPA. However in more proximal occlusions this was rare; and potentially harmful worsening of perfusion seen with change of occlusion site. We aimed to examine IV TPA related thrombus dynamics including migration further across both proximal and distal occlusions in a multicenter prospective cohort study INTERRSeCT.

Methods: Acute ischemic stroke patients with intracranial occlusion who had baseline CTA and follow-up CTA or initial run angio in INTERRSeCT and IV TPA were reviewed. We evaluated change of occlusion site (COS) and classified patients into 4 categories: Complete Recanalization (CR) of primary occlusive lesion with no remaining thrombus; definite Thrombus Migration (dTM) with primary occlusion site moved to a distal artery and occlusion site patent on baseline CTA; probable Thrombus Migration (pTM) with COS evident but initial occlusion extent not visualized; or No Change of occlusion site (NC).

Results: A total of 462 IV TPA patients were enrolled, 41% received EVT. Median time from TPA to follow-up imaging was 133 minutes. COS was seen in 50% of cases with CR in 15% and TM in 35% (dTM 12%, pTM 23%). Distal artery occlusion and longer interval of TPA to imaging were independent predictors for COS. In 62 proximal occlusion (ICA and proximal-mid M1 MCA) patients with follow-up imaging within 60 mins after TPA (receiving EVT in 94%), any TM showed a lower rate of 90-day mRS≤2 than NC (47% vs 78%, adjusted OR 0.21, 95%CI 0.04-0.87). No CR was seen in this early group.

Conclusions: Thrombus migration is common after IV TPA. Thrombus instability from IV TPA may worsen clinical outcome in proximal occlusions despite early EVT initiation, possibly due to migration of thrombus to distal arteries accelerating infarction or more challenging thrombectomy due to thrombus dispersion. The benefit of IV TPA prior to EVT at comprehensive stroke centers for ICA or prox-mid M1 occlusions require more study in randomized clinical trials.

[General medical care in French psychiatric units for inmates: A national survey]

OBJECTIVES

The UHSA (UHSA) are French psychiatric units for inmates which admit detainees suffering from a psychiatric disorder requiring full-time hospital care. Non-psychiatric pathologies are overrepresented in patients with psychiatric disorders but also in detainees. As a result, patients hospitalized in UHSA are largely exposed to non-psychiatric conditions, and exploring the organization of general medical care for these patients appears very relevant. The aim of this study is to review the general medical care in all French UHSA.

METHODS

A descriptive study was carried out through a survey of the nine facilities.

RESULTS

All UHSA benefit from the intervention of a general practitioner. The physical clinical examination, the biological assessment and the electrocardiogram are systematically performed at the patient's admission in 7, 5 and 9 establishments, respectively. However, the offer of general medical care in UHSA seems disparate and sometimes insufficient. Specialized consultations are regularly requested during hospitalizations, but no establishment benefits from a telemedicine system or specialized consultations on site. The extraction of the patient to the general hospital is therefore systematic when such a consultation is needed. But the number of penitentiary escorts per day is limited. In 6 UHSA, medical extractions are thus regularly canceled by the penitentiary administration, sometimes without a medical opinion. Finally, the patient's regular physician is only contacted in 3 UHSA during hospitalizations.

CONCLUSION

Based on these results, ways of improving the organization of general medical care in UHSA are proposed through four main axes: the structure and general organization; the general medical care; the link with the healthcare partners and the articulation with the penitentiary administration.

[Involuntary hospitalization: A survey of liberty and custody judges]

The procedure of involuntary hospitalization in France has been recently modified by the law of 5 July 2011. Since that time, a liberty and custody judge has been appointed to guarantee the rights of psychiatric inpatients and to prevent abusive hospitalizations. Currently, for one involuntary hospitalization in ten a release is decided by the liberty and custody judge although psychiatrists consider that psychiatric care is necessary. In order to improve our understanding of the role of liberty and custody judges, and how they make their decisions, we conducted a qualitative survey of liberty and custody judges in the Tribunal de Grande Instance of Lille. Three judges were questioned, based on a semi-structured interview. Judges' responses have highlighted the need for psychiatrists to strictly respect the legal procedures and to accurately describe the clinical signs and symptoms that justify the procedure of involuntary hospitalization in the medical certificates. The intervention of liberty and custody judges for patients with psychiatric disorders represents a breakthrough for patients' rights in France, reflecting that they are considered as citizens, with the same rights as others. Nonetheless, this new mission needs a progressive learning, based on mutual exchanges with doctors and caregivers.

Abstract WP62: Favorable Clot Characteristics Predict Smaller Infarct Volume in Acute Ischemic Stroke Patients Treated With Reperfusion Therapy

Introduction: Multiple studies have correlated larger final infarct volume (FIV) with worse clinical outcomes. In INTERRSeCT , an international multicenter prospective cohort study, we sought to determine the favorable intracranial clot characteristics predicting smaller infarct volumes.

Methods: FIV was measured (24 ±12 hours after baseline imaging) in 605 patients from INTERRSeCT study by blinded readers using Quantomo (Cybertrial Inc, Calgary). Clot Burden Score (CBS) is a 10-point scale with 10 referring to a completely patent ipsilateral anterior circulation from ICA to both M2 arteries, whereas 0 refers to a completely occluded ipsilateral anterior circulation. Residual Flow Grade (RFG) assesses the radiological permeability of the clot to contrast, with grade 0, 1, and 2 defined as no contrast, diffuse ghosting, and hairline lumen, respectively. Both of these scores were assessed by a blinded reader to the FIV. Using ordinal logistic regression, FIV was divided into deciles as the outcome. CBS and RFG were analyzed from 0 to 10, and 0 to 2, respectively. Two models were used, the first has no recanalization status, while the second included it.

Results: The median FIVs with and without recanalization were 12.34 ml (IQR: 32.3 ml) and 22.15 ml (IQR: 60.12ml), respectively. CBS and RFG were independently predictive of FIV (p-value= <0.001 and 0.003, respectively). The common ORs for having one decile higher FIV for 1 point increase in CBS and RFG were 0.82 (CI: 0.77, 0.87) and 0.66 (CI: 0.51, 0.86), respectively. After adjusting for recanalization, the common ORs for having one decile higher FIV for 1 point increase in CBS and RFG were 0.83 (CI: 0.78, 0.88) and 0.72 (CI: 0.54, 0.94), respectively.

Conclusions: Residual flow grade and clot burden score are fast and practical techniques for practitioners treating acute ischemic stroke patients. Favorable RFG and CBS independently, predict lower infarct volumes regardless of whether recanalization achieved.

[Involuntary psychiatric care for inmates in France: Only for "dangerous" patients?]

The unités hospitalières spécialement aménagées (UHSA) are full-time inpatient psychiatric units for inmates in France. Their creation has been associated with several advances in access to psychiatric care for inmates in recent years. However, there is still only one means of involuntary hospitalization for prisoners in France: care by decision of a representative of the state (les soins sur décision d'un représentant de l'état [SDRE]). Interestingly, for SDRE to be recognized as legal by the French judge, the patient must be "a danger to himself or to the others". Thus, there is a major difference with involuntary hospitalization outside the prison, and there are specific criteria for involuntary psychiatric hospitalization for inmates in France. This situation questions the general framework of involuntary psychiatric care and is very inconsistent with French law. Indeed, the goal of the loi n^o 94-43 du 18 janvier 1994 relating to public health and social protection is to ensure equivalent care for all patients, incarcerated or not.

Evidence for a role of eosinophils in blister formation in bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune bullous disease of the skin characterized by subepidermal blister formation due to tissue-bound and circulating autoantibodies to the hemidesmosomal antigens BP180 and BP230. Although eosinophils and their toxic mediators are found abundantly in BP lesions, their role in blister formation has remained unclear.

OBJECTIVE

To investigate the role of eosinophils in the pathogenesis of BP with a specific focus on blister formation and to define conditions inducing dermal-epidermal separation (DES).

METHODS

In an ex vivo human model of BP, normal human skin cryosections were incubated with purified human peripheral blood eosinophils with or without activation in the presence or absence of BP autoantibodies, brefeldin A, diphenyleneiodonium, DNase or blocking F(ab')₂ fragments to CD16, CD18, CD32 and CD64. Dermal-epidermal separation was assessed by light microscopy studies and quantified using Fiji software.

RESULTS

Following activation with IL-5 and in the presence of BP autoantibodies, eosinophils induced separation along the dermal-epidermal junction of ex vivo skin. Dermal-epidermal separation was significantly reduced by blocking any of the following: Fcγ receptor binding (P = 0.048), eosinophil adhesion (P = 0.046), reactive oxygen species (ROS) production (P = 0.002), degranulation (P < 0.0001) or eosinophil extracellular trap (EET) formation (P = 0.048).

CONCLUSIONS

Our results provide evidence that IL-5-activated eosinophils directly contribute to BP blister formation in the presence of BP autoantibodies. Dermal-epidermal separation by IL-5-activated eosinophils depends on adhesion and Fcγ receptor activation, requires elevated ROS production and degranulation and involves EET formation. Thus, targeting eosinophils may be a promising therapeutic approach for BP.

First Searches for Axions and Axionlike Particles with the LUX Experiment

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118  kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12  eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6  eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16  keV/c^{2}. These are the most stringent constraints to date for these interactions.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Abstract WP55: Through Thick and Thin: Improved Aspects Grading and Dense Vessel Detection Using Simple Ncct Post-processing

Introduction: Assessing Alberta Stroke Program Early CT Score (ASPECTS) and identifying hyperdense arteries on non-contrast CT (NCCT) are important components of decision-making in acute stroke. Conventional practice uses 5mm averaged slice thickness NCCT for interpretation of these features. We have systematically evaluated several post processing techniques on NCCT to determine if there is improved reliability in identification of ASPECTS and hyperdense artery.

Methodology: We assessed four post-processing techniques on NCCT namely (1) 5mm averaged thickness (2) Minimum Intensity Projection (mIP) - 5mm thickness (3) thin slices (0.625mm) and (4) Maximum Intensity Projection (MIP) - 5mm thickness (Figure 1). Three raters (student, fellow and expert) independently assessed 100 NCCT scans from the PRoveIT database. All scans were read at four different times 10-14 days apart. At each time-point the post processing modality was changed and the patient order randomized. Information on side of suspected infarction was provided. Raters were asked to score ASPECTS and identify presence of hyperdense artery at each reading. Inter-rater reliability was assessed using Intra-cluster correlation (ICC) for ASPECTS and weighted kappa (wKap) for hyperdense artery.

Results: The highest inter-rater reliability was found with the MIP technique (ICC 0.42; p<0.001), followed by 5 mm average, mIP and thin slice respectively (ICC 0.33, 0.32, 0.20; all p<0.01). Highest agreement for hyperdense vessel detection was noted with thin slice (wKap 0.30; p<0.001) followed by Average, MIPs and mIPs respectively (wKap 0.25, 0.18, 0.13; all p <0.05).

Conclusion: The use of MIP images for ASPECTS grading and thin images for hyperdense vessel detection improves reliability on NCCT. These simple processing steps are easily available on any modern scanner and may help improve patient care.

Abstract TP51: When Can Aspects be Read Reliably?

Introduction: Alberta Stroke Program Early CT Score (ASPECTS) is a systematic approach to assess early ischemic change on non-contrast CT (NCCT). Concerns have however been expressed about its reliability when making clinical decisions in patients with acute ischemic stroke. We chose to systematically assess technical, environmental and patient specific variables that potentially affect ASPECTS interpretation.

Methods: We randomly selected 150 patients with acute ischemic stroke from the PRoveIT database. All patients had baseline NCCT and CT angiography head and neck. Three raters (expert, fellow and trainee) read ASPECTS on the same NCCT three times (Sessions 1-3) at minimum interval of 10-14 days. Raters were kept blinded to follow-up data throughout the study. No baseline clinical information was provided in Session 1. Raters were provided clinical information (age, baseline NIHSS and side of stroke) in session 2 and additional multiphase CTA in session 3. Reading environment [room light and time pressure (<60 s for interpretation) vs. core lab] was altered during readings. Data on motion artifact, leukoaraiosis, old infarcts on NCCT were collected. Time taken for ASPECTS interpretation was collected across all the readings. Reliability was assessed using Intra-cluster correlation coefficient (ICC).

Results: The highest inter-rater reliability was found in session 3 (ICC 0.47; p<0.001). The rest of the analyses was restricted to session 3. Reliability in session 3 was not affected by time pressure or ambient light settings (all p<0.01). In session 3, patient motion (ICC 0.35 present vs. 0.49 absent) and old infarcts (ICC 0.42 present vs. 0.48 absent) worsened reliability; however presence of leukoaraiosis did not affect reliability (ICC 0.48 present vs. 0.46 absent). Mean time for ASPECT interpretation by trainee, fellow and expert were 38.9 s (+/-12.8s), 49.8 s (+/-15.4s) and 38.9 s (+/-14s) respectively.

Conclusion: ASPECTS interpretation on NCCT is most reliable when clinical and CTA information is available. Interpretation with this information is reliable even in a well-lit room and under time pressure, the environment that mimics real life acute stroke.