Automatic segmentation of hemorrhagic transformation on follow-up non-contrast CT after acute ischemic stroke.

Background: Hemorrhagic transformation (HT) following reperfusion therapies is a serious complication for patients with acute ischemic stroke. Segmentation and quantification of hemorrhage provides critical insights into patients' condition and aids in prognosis. This study aims to automatically segment hemorrhagic regions on follow-up non-contrast head CT (NCCT) for stroke patients treated with endovascular thrombectomy (EVT). Methods: Patient data were collected from 10 stroke centers across two countries. We propose a semi-automated approach with adaptive thresholding methods, eliminating the need for extensive training data and reducing computational demands. We used Dice Similarity Coefficient (DSC) and Lin's Concordance Correlation Coefficient (Lin's CCC) to evaluate the performance of the algorithm. Results: A total of 51 patients were included, with 28 Type 2 hemorrhagic infarction (HI2) cases and 23 parenchymal hematoma (PH) cases. The algorithm achieved a mean DSC of 0.66 ± 0.17. Notably, performance was superior for PH cases (mean DSC of 0.73 ± 0.14) compared to HI2 cases (mean DSC of 0.61 ± 0.18). Lin's CCC was 0.88 (95% CI 0.79-0.93), indicating a strong agreement between the algorithm's results and the ground truth. In addition, the algorithm demonstrated excellent processing time, with an average of 2.7 s for each patient case. Conclusion: To our knowledge, this is the first study to perform automated segmentation of post-treatment hemorrhage for acute stroke patients and evaluate the performance based on the radiological severity of HT. This rapid and effective tool has the potential to assist with predicting prognosis in stroke patients with HT after EVT.

Tranexamic acid versus placebo in individuals with intracerebral haemorrhage treated within 2 h of symptom onset (STOP-MSU): an international, double-blind, randomised, phase 2 trial.

BACKGROUND: Tranexamic acid, an antifibrinolytic agent, might attenuate haematoma growth after an intracerebral haemorrhage. We aimed to determine whether treatment with intravenous tranexamic acid within 2 h of an intracerebral haemorrhage would reduce haematoma growth compared with placebo. METHODS: STOP-MSU was an investigator-led, double-blind, randomised, phase 2 trial conducted at 24 hospitals and one mobile stroke unit in Australia, Finland, New Zealand, Taiwan, and Viet Nam. Eligible participants had acute spontaneous intracerebral haemorrhage confirmed on non-contrast CT, were aged 18 years or older, and could be treated with the investigational product within 2 h of stroke onset. Using randomly permuted blocks (block size of 4) and a concealed pre-randomised assignment procedure, participants were randomly assigned (1:1) to receive intravenous tranexamic acid (1 g over 10 min followed by 1 g over 8 h) or placebo (saline; matched dosing regimen) commencing within 2 h of symptom onset. Participants, investigators, and treating teams were masked to group assignment. The primary outcome was haematoma growth, defined as either at least 33% relative growth or at least 6 mL absolute growth on CT at 24 h (target range 18-30 h) from the baseline CT. The analysis was conducted within the estimand framework with primary analyses adhering to the intention-to-treat principle. The primary endpoint and secondary safety endpoints (mortality at days 7 and 90 and major thromboembolic events at day 90) were assessed in all participants randomly assigned to treatment groups who did not withdraw consent to use any data. This study was registered with ClinicalTrials.gov, NCT03385928, and the trial is now complete. FINDINGS: Between March 19, 2018, and Feb 27, 2023, 202 participants were recruited, of whom one withdrew consent for any data use. The remaining 201 participants were randomly assigned to either placebo (n=98) or tranexamic acid (n=103; intention-to-treat population). Median age was 66 years (IQR 55-77), and 82 (41%) were female and 119 (59%) were male; no data on race or ethnicity were collected. CT scans at baseline or follow-up were missing or of inadequate quality in three participants (one in the placebo group and two in the tranexamic acid group), and were considered missing at random. Haematoma growth occurred in 37 (38%) of 97 assessable participants in the placebo group and 43 (43%) of 101 assessable participants in the tranexamic acid group (adjusted odds ratio [aOR] 1·31 [95% CI 0·72 to 2·40], p=0·37). Major thromboembolic events occurred in one (1%) of 98 participants in the placebo group and three (3%) of 103 in the tranexamic acid group (risk difference 0·02 [95% CI -0·02 to 0·06]). By 7 days, eight (8%) participants in the placebo group and eight (8%) in the tranexamic acid group had died (aOR 1·08 [95% CI 0·35 to 3·35]) and by 90 days, 15 (15%) participants in the placebo group and 19 (18%) in the tranexamic acid group had died (aOR 1·61 [95% CI 0·65 to 3·98]). INTERPRETATION: Intravenous tranexamic acid did not reduce haematoma growth when administered within 2 h of intracerebral haemorrhage symptom onset. There were no observed effects on other imaging endpoints, functional outcome, or safety. Based on our results, tranexamic acid should not be used routinely in primary intracerebral haemorrhage, although results of ongoing phase 3 trials will add further context to these findings. FUNDING: Australian Government Medical Research Future Fund.

Association of Time to Thrombolysis With Early Reperfusion After Alteplase and Tenecteplase in Patients With Large Vessel Occlusion.

BACKGROUND AND OBJECTIVES: Early treatment with intravenous alteplase increases the probability of lytic-induced reperfusion in large vessel occlusion (LVO) patients. The relationship of tenecteplase-induced reperfusion and the timing of thrombolytic administration has not been explored. In this study, we performed a comparative analysis of tenecteplase and alteplase reperfusion rates and assessed their relationship to the time of thrombolytic administration. METHODS: Patients who were initially treated with a thrombolytic within 4.5 hours of symptom onset were pooled from the Royal Melbourne Stroke Registry, EXTEND-IA, EXTEND-IA TNK, and EXTEND-IA TNK part 2 trials. The primary outcome, thrombolytic-induced reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion at initial angiographic assessment (or repeat CT perfusion/angiography). We compared the treatment effect of tenecteplase and alteplase through fixed-effects Poisson regression modelling. RESULTS: Among 846 patients included in the primary analysis, early reperfusion was observed in 173 (20%) patients (tenecteplase: 98/470 [21%], onset-to-thrombolytic time: 132 minutes [interquartile range (IQR): 99-170], and thrombolytic-to-assessment time: 61 minutes [IQR: 39-96]; alteplase: 75/376 [19%], onset-to-thrombolytic time: 143 minutes [IQR: 105-180], thrombolytic-to-assessment time: 92 minutes [IQR: 63-144]). Earlier onset-to-thrombolytic administration times were associated with an increased probability of thrombolytic-induced reperfusion in patients treated with either tenecteplase (adjusted risk ratio [aRR] 1.05 per 15 minutes [95% confidence interval (CI) 1.00-1.12] or alteplase (aRR 1.06 per 15 minutes [95% CI 1.00-1.13]). Tenecteplase remained associated with higher rates of reperfusion vs alteplase after adjustment for onset-to-thrombolytic time, occlusion site, thrombolytic-to-assessment time, and study as a fixed effect, (adjusted incidence rate ratio: 1.41 [95% CI 1.02-1.93]). No significant treatment-by-time interaction was observed (p = 0.87). DISCUSSION: In patients with LVO presenting within 4.5 hours of symptom onset, earlier thrombolytic administration increased successful reperfusion rates. Compared with alteplase, tenecteplase was associated with a higher probability of lytic-induced reperfusion, independent of onset-to-lytic administration times. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifiers: NCT02388061, NCT03340493. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that among patients with LVO receiving a thrombolytic, reperfusion was more likely with tenecteplase than alteplase.

Covert Cerebrovascular Changes in People With Heart Disease: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: To determine the prevalence of silent brain infarction (SBI) and cerebral small vessel disease (CSVD) in adults with atrial fibrillation (AF), coronary artery disease, heart failure or cardiomyopathy, heart valve disease, and patent foramen ovale (PFO), with comparisons between those with and without recent stroke and an exploration of associations between heart disease and SBI/CSVD. METHODS: Medline, Embase, and Cochrane Library were systematically searched for hospital-based or community-based studies reporting SBI/CSVD in people with heart disease. Data were extracted from eligible studies. Outcomes were SBI (primary) and individual CSVD subtypes. Summary prevalence (95% confidence intervals [CIs]) were obtained using random-effects meta-analysis. Pooled prevalence ratios (PRs) (95% CI) were calculated to compare those with heart disease with available control participants without heart disease from studies. RESULTS: A total of 221 observational studies were included. In those with AF, the prevalence was 36% (31%-41%) for SBI (70 studies, N = 13,589), 25% (19%-31%) for lacune (26 studies, N = 7,172), 62% (49%-74%) for white matter hyperintensity/hypoattenuation (WMH) (34 studies, N = 7,229), and 27% (24%-30%) for microbleed (44 studies, N = 13,654). Stratification by studies where participants with recent stroke were recruited identified no differences in the prevalence of SBI across subgroups (phomogeneity = 0.495). Results were comparable across participants with different heart diseases except for those with PFO, in whom there was a lower prevalence of SBI [21% (13%-30%), 11 studies, N = 1,053] and CSVD. Meta-regressions after pooling those with any heart disease identified associations of increased (study level) age and hypertensives with more SBIs and WMH (pregression <0.05). There was no evidence of a difference in the prevalence of microbleed between those with and without heart disease (PR [95% CI] 1.1 [0.7-1.7]), but a difference was seen in the prevalence of SBI and WMH (PR [95% CI] 2.3 [1.6-3.1] and 1.7 [1.1-2.6], respectively). DISCUSSION: People with heart disease have a high prevalence of SBI (and CSVD), which is similar in those with vs without recent stroke. More research is required to assess causal links and implications for management. TRIAL REGISTRATION INFORMATION: PROSPERO CRD42022378272 (crd.york.ac.uk/PROSPERO/).

CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core.

BACKGROUND: Recent trials confirmed the effectiveness of endovascular therapy in patients with large ischemic cores. Yet the optimal neuroimaging modalities to define large core remains unclear. We tried to address this question by comparing the functional outcomes in patients receiving thrombectomy selected by either noncontrast computed tomography Alberta Stroke Program Early Computed Tomography Score (ASPECTS) or computed tomography perfusion (CTP). METHODS: This study retrospectively selected patients enrolled in the International Stroke Perfusion Registry between August 2011 and April 2022. Patients with acute stroke with large vessel occlusion in anterior circulation treated with endovascular therapy were included. All received both CTP and noncontrast computed tomography. The primary outcome was defined as poor functional outcome represented by a modified Rankin Scale score of 5 to 6 at 3 months. Large cores were defined in terms of either (1) noncontrast computed tomography ASPECTS ≤5 or (2) core volume ≥70 mL on CTP. RESULTS: A total of 1115 patients were included in the analysis, of which 90 patients had ASPECTS ≤5 (8.1%) and 97 patients CTP core ≥70 mL (8.7%). A fair agreement between ASPECTS and CTP with a κ value of 0.31 (0.21-0.40) was found. Compared with patients with neither CTP nor ASPECTS large cores, those with only ASPECTS-defined large cores (ie, ASPECTS ≤5; n=56) did not have a higher adjusted odds of poor outcome (29%; odds ratio, 1.84 [0.91-3.73]; P=0.089). However, patients with CTP large core but not ASPECTS-defined large core (n=63) had a higher adjusted odds of poor outcome (60%; odds ratio, 3.91 [2.01-7.60]; P<0.001). In time-stratified subgroup analysis (>6 versus ≤6 hours), ASPECTS showed no discriminative difference between ≤5 and >5 in poor outcome for patients receiving endovascular therapy within 6 hours. CONCLUSIONS: CTP core ≥70 mL-defined large cores are more predictive of poor outcome than ASPECTS ≤5-defined core in endovascular therapy patients, particularly within 6 hours after stroke onset.

Novel artificial intelligence-based hypodensity detection tool improves clinician identification of hypodensity on non-contrast computed tomography in stroke patients.

Introduction: In acute stroke, identifying early changes (parenchymal hypodensity) on non-contrast CT (NCCT) can be challenging. We aimed to identify whether the accuracy of clinicians in detecting acute hypodensity in ischaemic stroke patients on a non-contrast CT is improved with the use of an Artificial Intelligence (AI) based, automated hypodensity detection algorithm (HDT) using MRI-DWI as the gold standard. Methods: The study employed a case-crossover within-clinician design, where 32 clinicians were tasked with identifying hypodensity lesions on NCCT scans for five a priori selected patient cases, before and after viewing the AI-based HDT. The DICE similarity coefficient (DICE score) was the primary measure of accuracy. Statistical analysis compared DICE scores with and without AI-based HDT using mixed-effects linear regression, with individual NCCT scans and clinicians as nested random effects. Results: The AI-based HDT had a mean DICE score of 0.62 for detecting hypodensity across all NCCT scans. Clinicians' overall mean DICE score was 0.33 (SD 0.31) before AI-based HDT implementation and 0.40 (SD 0.27) after implementation. AI-based HDT use was associated with an increase of 0.07 (95% CI: 0.02-0.11, p = 0.003) in DICE score accounting for individual scan and clinician effects. For scans with small lesions, clinicians achieved a mean increase in DICE score of 0.08 (95% CI: 0.02, 0.13, p = 0.004) following AI-based HDT use. In a subgroup of 15 trainees, DICE score improved with AI-based HDT implementation [mean difference in DICE 0.09 (95% CI: 0.03, 0.14, p = 0.004)]. Discussion: AI-based automated hypodensity detection has potential to enhance clinician accuracy of detecting hypodensity in acute stroke diagnosis, especially for smaller lesions, and notably for less experienced clinicians.

Clinical relevance of intracranial hemorrhage after thrombectomy versus medical management for large core infarct: a secondary analysis of the SELECT2 randomized trial.

BACKGROUND: The incidence of intracerebral hemorrhage (ICH) and its effect on the outcomes after endovascular thrombectomy (EVT) for patients with large core infarcts have not been well-characterized. METHODS: SELECT2 trial follow-up imaging was evaluated using the Heidelberg Bleeding Classification (HBC) to define hemorrhage grade. The association of ICH with clinical outcomes and treatment effect was examined. RESULTS: Of 351 included patients, 194 (55%) and 189 (54%) demonstrated intracranial and intracerebral hemorrhage, respectively, with a higher incidence in EVT (134 (75%) and 130 (73%)) versus medical management (MM) (60 (35%) and 59 (34%), both P<0.001). Hemorrhagic infarction type 1 (HBC=1a) and type 2 (HBC=1b) accounted for 93% of all hemorrhages. Parenchymal hematoma (PH) type 1 (HBC=1c) and type 2 (HBC=2) were observed in 1 (0.6%) EVT-treated and 4 (2.2%) MM patients. Symptomatic ICH (sICH) (SITS-MOST definition) was seen in 0.6% EVT patients and 1.2% MM patients. No trend for ICH with core volumes (P=0.10) or Alberta Stroke Program Early CT Score (ASPECTS) (P=0.74) was observed. Among EVT patients, the presence of any ICH did not worsen clinical outcome (modified Rankin Scale (mRS) at 90 days: 4 (3-6) vs 4 (3-6); adjusted generalized OR 1.00, 95% CI 0.68 to 1.47, P>0.99) or modify EVT treatment effect (Pinteraction=0.77). CONCLUSIONS: ICH was present in 75% of the EVT population, but PH or sICH were infrequent. The presence of any ICH did not worsen functional outcomes or modify EVT treatment effect at 90-day follow-up. The high rate of hemorrhages overall still represents an opportunity for adjunctive therapies in EVT patients with a large ischemic core.

Large vessel occlusive stroke with milder baseline severity shows better collaterals and reduced harm from thrombectomy transfer delays.

BACKGROUND: Patients with large vessel occlusion (LVO) stroke presenting with milder baseline clinical severity are common and require endovascular thrombectomy. However, such patients are difficult to recognize using pre-hospital severity-based triage tools and therefore are likely to require a secondary inter-hospital transfer if transported to a non-thrombectomy center. Given the potential for milder severity to represent better underlying cerebrovascular collateral circulation, it is unknown whether transfer delays are still associated with poorer post-stroke outcomes in this patient group. AIMS: We primarily aimed to examine whether the harmful effect of inter-hospital transfer delay for thrombectomy was different for LVO patients with mild or severe deficits. Secondarily, we also investigated whether imaging markers of collateral circulation were different between severity groups. METHODS: Registry data from two large Australian thrombectomy centers were used to identify all directly presenting and secondarily transferred LVO patients undergoing thrombectomy, divided into those with lower (NIHSS < 10) and higher (NIHSS ⩾ 10) baseline deficits. The primary outcome was the functional independence or return to baseline defined as modified Rankin Scale 0-2 or baseline at 90 days. Patients with complete baseline CT-perfusion data were analyzed for imaging markers of collateral circulation by baseline severity group. RESULTS: A total of 1210 LVO patients undergoing thrombectomy were included, of which 273 (22.6%) had lower baseline severity. Despite similar thrombolysis and recanalization rates, transferred patients had lower odds of achieving the primary outcome compared to the primary presentation to a thrombectomy center, where baseline severity was higher (adjusted odds ratio (aOR) 0.759 (95% CI 0.576-0.999)), but not when severity was lower (aOR 1.357 (95% CI 0.764-2.409), p-interaction = 0.122). In the imaging analysis of 436 patients, those with milder severity showed smaller median ischemic core volumes (12.6 (IQR 0.0-17.9) vs 27.5 (IQR 6.5-37.1) mL, p < 0.001)), higher median perfusion mismatch ratio (10.8 (IQR 4.8-54.5) vs 6.6 (IQR 3.5-16.5), p < 0.001), and lower median hypoperfusion intensity ratio (0.25 (IQR 0.18-0.38) vs 0.40 (IQR 0.22-0.57), p < 0.001). DISCUSSION: Patients receiving secondary inter-hospital transfer for thrombectomy had poorer outcomes compared to those presenting directly to a thrombectomy center if baseline deficits were severe, but this difference was not observed when baseline deficits were milder. This result may potentially be due to our secondary findings of significantly improved collateral circulation markers in lower-severity LVO patients. As such, failure of pre-hospital screening tools to detect lower-severity LVO patients for pre-hospital bypass to a thrombectomy center may not necessarily deleteriously affect outcome. DATA ACCESS STATEMENT: Anonymized data not published within this article will be made available on request from any qualified investigator.

Endovascular Thrombectomy for Large Ischemic Stroke Across Ischemic Injury and Penumbra Profiles.

Importance: Whether endovascular thrombectomy (EVT) efficacy for patients with acute ischemic stroke and large cores varies depending on the extent of ischemic injury is uncertain. Objective: To describe the relationship between imaging estimates of irreversibly injured brain (core) and at-risk regions (mismatch) and clinical outcomes and EVT treatment effect. Design, Setting, and Participants: An exploratory analysis of the SELECT2 trial, which randomized 352 adults (18-85 years) with acute ischemic stroke due to occlusion of the internal carotid or middle cerebral artery (M1 segment) and large ischemic core to EVT vs medical management (MM), across 31 global centers between October 2019 and September 2022. Intervention: EVT vs MM. Main Outcomes and Measures: Primary outcome was functional outcome-90-day mRS score (0, no symptoms, to 6, death) assessed by adjusted generalized OR (aGenOR; values >1 represent more favorable outcomes). Benefit of EVT vs MM was assessed across levels of ischemic injury defined by noncontrast CT using ASPECTS score and by the volume of brain with severely reduced blood flow on CT perfusion or restricted diffusion on MRI. Results: Among 352 patients randomized, 336 were analyzed (median age, 67 years; 139 [41.4%] female); of these, 168 (50%) were randomized to EVT, and 2 additional crossover MM patients received EVT. In an ordinal analysis of mRS at 90 days, EVT improved functional outcomes compared with MM within ASPECTS categories of 3 (aGenOR, 1.71 [95% CI, 1.04-2.81]), 4 (aGenOR, 2.01 [95% CI, 1.19-3.40]), and 5 (aGenOR, 1.85 [95% CI, 1.22-2.79]). Across strata for CT perfusion/MRI ischemic core volumes, aGenOR for EVT vs MM was 1.63 (95% CI, 1.23-2.16) for volumes ≥70 mL, 1.41 (95% CI, 0.99-2.02) for ≥100 mL, and 1.47 (95% CI, 0.84-2.56) for ≥150 mL. In the EVT group, outcomes worsened as ASPECTS decreased (aGenOR, 0.91 [95% CI, 0.82-1.00] per 1-point decrease) and as CT perfusion/MRI ischemic core volume increased (aGenOR, 0.92 [95% CI, 0.89-0.95] per 10-mL increase). No heterogeneity of EVT treatment effect was observed with or without mismatch, although few patients without mismatch were enrolled. Conclusion and Relevance: In this exploratory analysis of a randomized clinical trial of patients with extensive ischemic stroke, EVT improved clinical outcomes across a wide spectrum of infarct volumes, although enrollment of patients with minimal penumbra volume was low. In EVT-treated patients, clinical outcomes worsened as presenting ischemic injury estimates increased. Trial Registration: ClinicalTrials.gov Identifier: NCT03876457.

Endovascular thrombectomy plus medical care versus medical care alone for large ischaemic stroke: 1-year outcomes of the SELECT2 trial.

BACKGROUND: Multiple randomised trials have shown efficacy and safety of endovascular thrombectomy in patients with large ischaemic stroke. The aim of this study was to evaluate long-term (ie, at 1 year) evidence of benefit of thrombectomy for these patients. METHODS: SELECT2 was a phase 3, open-label, international, randomised controlled trial with blinded endpoint assessment, conducted at 31 hospitals in the USA, Canada, Spain, Switzerland, Australia, and New Zealand. Patients aged 18-85 years with ischaemic stroke due to proximal occlusion of the internal carotid artery or of the first segment of the middle cerebral artery, showing large ischaemic core on non-contrast CT (Alberta Stroke Program Early Computed Tomographic Score of 3-5 [range 0-10, with lower values indicating larger infarctions]) or measuring 50 mL or more on CT perfusion and MRI, were randomly assigned, within 24 h of ischaemic stroke onset, to thrombectomy plus medical care or to medical care alone. The primary outcome for this analysis was the ordinal modified Rankin Scale (range 0-6, with higher scores indicating greater disability) at 1-year follow-up in an intention-to-treat population. The trial is registered at ClinicalTrials.gov (NCT03876457) and is completed. FINDINGS: The trial was terminated early for efficacy at the 90-day follow-up after 352 patients had been randomly assigned (178 to thrombectomy and 174 to medical care only) between Oct 11, 2019, and Sept 9, 2022. Thrombectomy significantly improved the 1-year modified Rankin Scale score distribution versus medical care alone (Wilcoxon-Mann-Whitney probability of superiority 0·59 [95% CI 0·53-0·64]; p=0·0019; generalised odds ratio 1·43 [95% CI 1·14-1·78]). At the 1-year follow-up, 77 (45%) of 170 patients receiving thrombectomy had died, compared with 83 (52%) of 159 patients receiving medical care only (1-year mortality relative risk 0·89 [95% CI 0·71-1·11]). INTERPRETATION: In patients with ischaemic stroke due to a proximal occlusion and large core, thrombectomy plus medical care provided a significant functional outcome benefit compared with medical care alone at 1-year follow-up. FUNDING: Stryker Neurovascular.

Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review.

BACKGROUND AND OBJECTIVES: Cardiovascular disease contributes significantly to disease burden among many Indigenous populations. However, data on stroke incidence in Indigenous populations are sparse. We aimed to investigate what is known of stroke incidence in Indigenous populations of countries with a very high Human Development Index (HDI), locating the research in the broader context of Indigenous health. METHODS: We identified population-based stroke incidence studies published between 1990 and 2022 among Indigenous adult populations of developed countries using PubMed, Embase, and Global Health databases, without language restriction. We excluded non-peer-reviewed sources, studies with fewer than 10 Indigenous people, or not covering a 35- to 64-year minimum age range. Two reviewers independently screened titles, abstracts, and full-text articles and extracted data. We assessed quality using "gold standard" criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and CONSIDER criteria for reporting of Indigenous health research. An Indigenous Advisory Board provided oversight for the study. RESULTS: From 13,041 publications screened, 24 studies (19 full-text articles, 5 abstracts) from 7 countries met the inclusion criteria. Age-standardized stroke incidence rate ratios were greater in Aboriginal and Torres Strait Islander Australians (1.7-3.2), American Indians (1.2), Sámi of Sweden/Norway (1.08-2.14), and Singaporean Malay (1.7-1.9), compared with respective non-Indigenous populations. Studies had substantial heterogeneity in design and risk of bias. Attack rates, male-female rate ratios, and time trends are reported where available. Few investigators reported Indigenous stakeholder involvement, with few studies meeting any of the CONSIDER criteria for research among Indigenous populations. DISCUSSION: In countries with a very high HDI, there are notable, albeit varying, disparities in stroke incidence between Indigenous and non-Indigenous populations, although there are gaps in data availability and quality. A greater understanding of stroke incidence is imperative for informing effective societal responses to socioeconomic and health disparities in these populations. Future studies into stroke incidence in Indigenous populations should be designed and conducted with Indigenous oversight and governance to facilitate improved outcomes and capacity building. REGISTRATION INFORMATION: PROSPERO registration: CRD42021242367.

A systematic review of discrete choice experiments in stroke rehabilitation.

OBJECTIVES: Existing research qualitatively explores consumer preferences for stroke rehabilitation interventions. However, it remains unclear which intervention characteristics are most important to consumers, and how these preferences may influence uptake and participation. Discrete choice experiments (DCE) provide a unique way to quantitatively measure preferences for health and health care. This study aims to explore how DCEs have been used in stroke rehabilitation and to identify reported consumer preferences for rehabilitation interventions. MATERIAL AND METHODS: A systematic review of published stroke rehabilitation DCEs was completed (PROSPERO registration: CRD42021282578). Six databases (including CINAHL, MEDLINE, EconLIT) were searched from January 2000-March 2023. Data extracted included topic area, sample size, aim, attributes, design process, and preference outcomes. Descriptive and thematic analyses were conducted, and two methodological checklists applied to review quality. RESULTS: Of 2,446 studies screened, five were eligible. Studies focused on exercise preference (n = 3), the structure and delivery of community services (n = 1), and self-management programs (n = 1). All had small sample sizes (range 50-146) and were of moderate quality (average score of 77%). Results indicated people have strong preferences for one-to-one therapy (over group-based), light-moderate intensity of exercise, and delivery by qualified therapists (over volunteers). CONCLUSIONS: Few DCEs have been conducted in stroke rehabilitation, suggesting consumer preferences could be more rigorously explored. Included studies were narrow in the scope of attributes included, limiting their application to practice and policy. Further research is needed to assess the impact of differing service delivery models on uptake and participation.

CHinese Acute Tissue-Based Imaging Selection for Lysis In Stroke Tenecteplase II (CHABLIS-T II): rationale and design.

BACKGROUND AND PURPOSE: Tenecteplase (TNK) has demonstrated non-inferiority to alteplase in patients who had an acute ischaemic stroke presenting within 4.5 hours from symptom onset. The trial is aimed to explore the efficacy and safety of TNK in Chinese patients who had an acute ischaemic stroke with large/medium vessel occlusion in an extended time window. METHODS AND DESIGN: Chinese Acute Tissue-Based Imaging Selection for Lysis In Stroke Tenecteplase II (CHABLIS-T II) is a multicentre, prospective, block-randomised, open-label, blinded-endpoint, phase IIb study. Eligible patients are 1:1 randomised into two groups: 0.25 mg/kg TNK versus best medical management (excluding TNK). The safety and efficacy of 0.25 mg/kg TNK are assessed through reperfusion status and presence of symptomatic intracranial haemorrhage (sICH). STUDY OUTCOMES: The primary outcome is major reperfusion without sICH at 24-48 hours after randomisation. Major reperfusion is defined as restoration of blood flow to greater than 50% of the involved ischaemic territory assessed by catheter angiography or repeated perfusion imaging. Secondary outcomes include post-thrombolytic recanalisation, neurological improvements, change in the National Institutes of Health Stroke Scale score, haemorrhagic transformation at 24-48 hours, systematic bleeding at discharge, modified Rankin Scale (mRS) 0-1, mRS 0-2, mRS 5-6, mRS distribution and Barthel index at 90 days. DISCUSSION: CHABLIS-T II will provide important evidence of intravenous thrombolysis with TNK for patients who had an acute stroke in an extended time window.

The Scottish Medical Imaging Archive: 57.3 Million Radiology Studies Linked to Their Medical Records.

Keywords: MRI, Imaging Sequences, Ultrasound, Mammography, CT, Angiography, Conventional Radiography Published under a CC BY 4.0 license. See also the commentary by Whitman and Vining in this issue.

Outcomes associated to the time to treatment with intravenous tenecteplase for acute ischaemic stroke: subgroup analysis of the TRACE-2 randomised controlled clinical trial.

BACKGROUND: The benefit of intravenous alteplase in acute ischaemic stroke (AIS) is time-dependent. Tenecteplase is non-inferior to alteplase among patients with AIS. We aimed to delineate the association of the stroke onset to treatment time (OTT) with tenecteplase compared with alteplase on therapeutic benefit and clinical risks. METHODS: This is a post hoc analysis of the Tenecteplase Reperfusion therapy in Acute ischaemic Cerebrovascular Events-2 an open-label, randomised, controlled, non-inferior trial. A total of 1430 AIS within 4.5 hours onset at 53 sites in China from 12 June 2021 to 29 May 2022 were randomly assigned (1:1) to receive either tenecteplase 0.25 mg/kg or alteplase 0.9 mg/kg. The primary efficacy outcome was the proportion of participants with a modified Rankin Scale score of 0-1 at 90 days. A post hoc subgroup analysis was conducted with the OTT divided into three intervals (0-90 min, 91-180 min and 181-270 min). The primary safety outcome was symptomatic intracranial haemorrhage within 36 hours post-thrombolytic treatment. RESULTS: Treatment was initiated within 270 min of stroke onset in 1412 patients who were randomly allocated to either tenecteplase (n=707) or alteplase (n=705). The OR of primary efficacy outcome was similar as OTT increased (p=0.84). Adjusted odds of an excellent functional outcome were 0.99 (95% CI 0.37 to 2.67) for 0-90 min, 1.23 (95% CI 0.88 to 1.71) for 91-180 min and 1.21 (95% CI 0.88 to 1.65) for 181-270 min. All were in favour of the tenecteplase group. Meta-analysis of 2949 patients yielded a pooled risk difference of 5.54 (95% CI -0.18 to 11.26; p=0.82) in favour of tenecteplase for more than 180 min and 1.77 (95% CI -2.66 to 6.20; p=0.58) for 0-180 min. CONCLUSIONS: In AIS patients who were treated with either tenecteplase or alteplase within 4.5 hours onset, there was no difference observed in the efficacy and safety between the two groups at the three different OTT time intervals.

Tenecteplase thrombolysis for stroke up to 24 hours after onset with perfusion imaging selection: the umbrella phase IIa CHABLIS-T randomised clinical trial.

BACKGROUND: The performance of intravenous tenecteplase in patients who had an acute ischaemic stroke with large/medium vessel occlusion or severe stenosis in an extended time window remains unknown. We investigated the promise of efficacy and safety of different doses of tenecteplase manufactured in China, in patients who had an acute ischaemic stroke with large/medium vessel occlusion beyond 4.5-hour time window. METHODS: The CHinese Acute tissue-Based imaging selection for Lysis In Stroke-Tenecteplase was an investigator-initiated, umbrella phase IIa, open-label, blinded-endpoint, Simon's two-stage randomised clinical trial in 13 centres across mainland China. Participants who had salvageable brain tissue on automated perfusion imaging and presented within 4.5-24 hours from time of last seen well were randomised to receive 0.25 mg/kg tenecteplase or 0.32 mg/kg tenecteplase, both with a bolus infusion over 5-10 s. The primary outcome was proportion of patients with promise of efficacy and safety defined as reaching major reperfusion without symptomatic intracranial haemorrhage at 24-48 hours after thrombolysis. Assessors were blinded to treatment allocation. All participants who received tenecteplase were included in the analysis. RESULTS: A total of 86 patients who had an acute ischaemic stroke identified with anterior large/medium vessel occlusion or severe stenosis were included in this study from November 2019 to December 2021. All of the 86 patients enrolled either received 0.25 mg/kg (n=43) or 0.32 mg/kg (n=43) tenecteplase, and were available for primary outcome analysis. Fourteen out of 43 patients in the 0.25 mg/kg tenecteplase group and 10 out of 43 patients in the 0.32 mg/kg tenecteplase group reached the primary outcome, providing promise of efficacy and safety for both doses based on Simon's two-stage design. DISCUSSION: Among patients with anterior large/medium vessel occlusion and significant penumbral mismatch presented within 4.5-24 hours from time of last seen well, tenecteplase 0.25 mg/kg and 0.32 mg/kg both provided sufficient promise of efficacy and safety. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT04086147, https://clinicaltrials.gov/ct2/show/NCT04086147).

Early anticoagulation in patients with stroke and atrial fibrillation is associated with fewer ischaemic lesions at 1 month: the ATTUNE study.

BACKGROUND: The optimal time to commence anticoagulation in patients with atrial fibrillation (AF) after ischaemic stroke or transient ischaemic attack (TIA) is unclear, with guidelines differing in recommendations. A limitation of previous studies is the focus on clinically overt stroke, rather than radiologically obvious diffusion-weighted imaging ischaemic lesions. We aimed to quantify silent ischaemic lesions and haemorrhages on MRI at 1 month in patients commenced on early (<4 days) vs late (≥4 days) anticoagulation. We hypothesised that there would be fewer ischaemic lesions and more haemorrhages in the early anticoagulant group at 1-month MRI. METHODS: A prospective multicentre, observational cohort study was performed at 11 Australian stroke centres. Clinical and MRI data were collected at baseline and follow-up, with blinded imaging assessment performed by two authors. Timing of commencement of anticoagulation was at the discretion of the treating stroke physician. RESULTS: We recruited 276 patients of whom 208 met the eligibility criteria. The average age was 74.2 years (SD±10.63), and 79 (38%) patients were female. Median National Institute of Health Stroke Scale score was 5 (IQR 1-12). Median baseline ischaemic lesion volume was 5 mL (IQR 2-17). There were a greater number of new ischaemic lesions on follow-up MRI in patients commenced on anticoagulation ≥4 days after index event (17% vs 8%, p=0.04), but no difference in haemorrhage rates (22% vs 32%, p=0.10). Baseline ischaemic lesion volume of ≤5 mL was less likely to have a new haemorrhage at 1 month (p=0.02). There was no difference in haemorrhage rates in patients with an initial ischaemic lesion volume of >5 mL, regardless of anticoagulation timing. CONCLUSION: Commencing anticoagulation <4 days after stroke or TIA is associated with fewer ischaemic lesions at 1 month in AF patients. There is no increased rate of haemorrhage with early anticoagulation. These results suggest that early anticoagulation after mild-to-moderate acute ischaemic stroke associated with AF might be safe, but randomised controlled studies are needed to inform clinical practice.

Rationale and design of Tenecteplase Reperfusion Therapy in Acute Ischaemic Cerebrovascular Events III (TRACE III): a randomised, phase III, open-label, controlled trial.

BACKGROUND AND PURPOSE: Recombinant human TNK tissue-type plasminogen activator (rhTNK-tPA) was not inferior to alteplase for ischaemic stroke within 4.5 hours. Our study aimed to investigate the efficacy and safety of rhTNK-tPA in patients who had an ischaemic stroke due to large vessel occlusion (LVO) of anterior circulation beyond 4.5 hours. METHODS AND DESIGN: Tenecteplase Reperfusion Therapy in Acute Ischaemic Cerebrovascular Events-III (TRACE III) is a multicentre, prospective, randomised, open-label, blind endpoint, controlled clinical trial. Patients who had an ischaemic stroke due to anterior circulation LVO (internal carotid artery, middle cerebral artery M1 and M2 segments) within 4.5-24 hours from last known well (including wake-up stroke and no witness stroke) and with salvageable tissue (ischaemic core volume <70 mL, mismatch ratio ≥1.8 and mismatch volume ≥15 mL) based on CT perfusion or MRI perfusion-weighted imaging (PWI) were included and randomised to rhTNK-tPA 0.25 mg/kg (single bolus) to a maximum of 25 mg or standard medical therapy. Specially, we will exclude patients who are intended for direct thrombectomy. All will be followed up for 90 days. STUDY OUTCOMES: Primary efficacy outcome is modified Rankin Scale (mRS) score ≤1 at 90 days. Secondary efficacy outcomes include ordinal distribution of mRS at 90 days, major neurological improvement defined by a decrease ≥8 points compared with the initial deficit or a score ≤1 on the National Institutes of Health Stroke Scale (NIHSS) at 72 hours, mRS score ≤2 at 90 days, the rate of improvement on Tmax >6 s at 24 hours and NIHSS score change from baseline at 7 days. Safety outcomes are symptomatic intracerebral haemorrhage within 36 hours and mortality at 90 days. DISCUSSION: TRACE III will provide evidence for the efficacy and safety of rhTNK-tPA in patients who had an ischaemic strokes due to anterior circulation LVO beyond 4.5 hours. TRIAL REGISTRATION NUMBER: NCT05141305.

Role of cardiac computed tomography in hyperacute stroke assessment.

BACKGROUND: Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary. METHODS: Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT. RESULTS: A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS ≥4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%). CONCLUSIONS: A cutoff NIHSS ≥4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

Asymmetric deep cerebral venous filling predicts poor outcome of acute basilar artery occlusion after endovascular treatment.

OBJECTIVE: To explore the relationship between asymmetric deep cerebral venous (ADCV) filling and poor outcomes after endovascular treatment (EVT) in patients with acute basilar artery occlusion (ABAO). METHODS: ABAO patients were selected from a prospectively collected data at our center. The DCV filling was evaluated using computed tomography perfusion (CTP)-derived reconstructed 4D-DSA or mean venous map. ADCV filling was defined as the internal cerebral vein (ICV), thalamostriate vein (TSV), or basal vein of Rosenthal (BVR) presence of ipsilateral filling defects or delayed opacification compared to the contralateral side. Poor prognosis was defined as a modified Rankin scale score >3 at the 90-day follow-up. RESULTS: A total of 90 patients were enrolled in the study, with a median Glasgow Coma Scale of 6, 46 (51.1%) showed ADCV filling, 59 (65.6%) had a poor prognosis, and 27 (30.7%) had malignant cerebellar edema (MCE). Multivariate adjusted analysis revealed significant associations between asymmetric TSV and poor prognosis (odds ratio, 9.091, p = 0.006); asymmetric BVR (OR, 9.232, p = 0.001) and asymmetric ICV (OR, 4.028, p = 0.041) were significantly associated with MCE. CONCLUSION: Preoperative ADCV filling is an independent influencing factor for the poor outcome after EVT in ABAO patients.