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The expanded Thrombolysis in Cerebral Infarction (eTICI) scale is the default method to measure reperfusion success of endovascular treatment for acute ischemic stroke. It is an estimate of the percentage of the vascular territory affected by the initial occlusion, or target downstream territory (TDT), that is reperfused after the intervention. Traditionally, the size of the TDT is determined on the preinterventional catheter angiography images by delineating the antegrade capillary deficit caused by the catheter angiography target occlusion. As such, the current definition of eTICI grading is only suitable to estimate the efficacy of reperfusion strategies occurring after the baseline catheter angiogram. However, reperfusion therapy for acute ischemic stroke due to large vessel occlusion often encompasses intravenous thrombolysis therapy started prior to endovascular treatment but after cross‐sectional vascular imaging (computed tomography or magnetic resonance imaging) used to determine eligibility for endovascular treatment. The inherent shortcomings of the current eTICI scale to quantify preinterventional perfusion changes are discussed. We then argue that depending on the timing of the studied intervention – either between cross‐sectional imaging and endovascular treatment or after first intracranial catheter angiography – the TDT used to determine the eTICI grade should be based on the occlusion as seen on admission cross‐sectional vascular imaging or prethrombectomy catheter angiography, respectively. We propose a new conceptual framework to grade reperfusion based on the TDT derived from the occlusion seen on cross‐sectional vascular imaging: the cross‐sectional eTICI. Last, we discuss how this definition of the TDT more reliably measures preinterventional reperfusion and establishes homogenous definitions of embolization and infarctions in new territories.

Background: Contrast-induced encephalopathy (CIE) is a rare adverse event linked to intravascular use of iodine-containing contrast media. The prevalence of CIE could increase in the future due to growing numbers of endovascular procedures. We provide insights from a case series of 7 patients. Methods: Cases from 3 centers were collected based on existing academic collaborations, and key factors were extracted to illustrate development and management of CIE. Results: In our retrospective case-series analysis of 7 cases from 3 countries, affected patients had an equal distribution of sex (4 women, 3 men) and a median age of 75 (IQR 63-77). Common risk factors included hypertension (5/7), hyperlipidemia (5/7), previous stroke (3/7), and type 2 diabetes (3/7). CIE developed in 3 cases after endovascular thrombectomy (EVT) for stroke, in 2 cases after aneurysm treatment, in 1 case after cardiac catheterization, and in 1 case after diagnostic computed tomography (CT) angiography without an endovascular procedure. The median procedure time was 48 min (IQR 40-81). All patients received non-ionic, low-osmolar contrast agents with volumes ranging from 100-300 ml. Symptom onset was close to contrast administration, with stroke-like neurological deficits being most common (4/7). Prednisolone was the most frequently used medication to treat the symptoms (4/7). Symptom resolution occurred in 4 out of 7 patients within two to several days, and 1 patient died, but without clear connection to CIE. Conclusion: CIE is a rare and possibly underrecognized condition, but fortunately, with a favorable outcome in most cases.

Background Ideally, medical research provides crucial data about disease processes, diagnoses, prognoses, treatment targets and outcomes, and systems of care. However, medical research is costly, and funding is difficult to receive because the processes are highly competitive. There is a paucity of data on the perspectives of researchers, funders, patients and the public about current funding paradigms. This study sought to understand the priorities and opinions of each group to better guide meaningful innovation in research funding processes.Method In this Priorities & Expectations of Researchers, Funders, Patients and the Public Regarding the Funding & Conduct of Stroke Research study, we conducted in-depth interviews with medical researchers, funders, patients and members of the general public to learn their opinions of the current funding process and thoughts about alternative approaches. We used both purposive and snowball sampling to recruit participants and conducted semistructured interviews. The study ended when thematic saturation was attained. Qualitative analysis followed inductive grounded theory methodology.Results 41 interviews were completed (11 researchers, 10 funders, 10 patients, 10 members of the general public; 61% female). Interviewees expressed a high interest in supporting a comprehensive evaluation of the research grant funding process while integrating funding mechanisms that are more inclusive and reduce bias in topic selection and researchers who receive funds. Participants acknowledged a gap in patient and public involvement in setting a research agenda, choosing topics to be studied and focusing on specific outcomes. Crowdfunding was identified as an alternative strategy that could facilitate research democratisation; however, participants emphasised the importance of expert review of research proposals, as in current processes to continue to support rigour and trust in research proposal quality.Conclusion Our research revealed stakeholder concerns about the transparency and equity of current research funding paradigms. Suggestions to democratize research and explore alternative fundraising platforms necessitate a fundamental shift in traditional research funding processes.

Background and Purpose Infarct volume and other imaging markers are increasingly used as surrogate measures for clinical outcome in acute ischemic stroke research, but how improvements in these imaging surrogates translate into better clinical outcomes is currently unclear. We investigated how changes in infarct volume at 24 hours alter the probability of achieving good clinical outcome (modified Rankin Scale [mRS] 0–2). Methods Data are from endovascular thrombectomy patients from the randomized controlled ESCAPE-NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischaemic Stroke) trial. Infarct volume at 24 hours was manually segmented on non-contrast computed tomography or diffusion-weighted magnetic resonance imaging. Probabilities of achieving good outcome based on infarct volume were obtained from a multivariable logistic regression model. The probability of good outcome was plotted against infarct volume using linear spline regression. Results A total of 1,099 patients were included in the analysis (median final infarct volume 24.9 mL [interquartile range: 6.6–92.2]). The relationship between total infarct volume and good outcome probability was nearly linear for infarct volumes between 0 mL and 250 mL. In this range, a 10% increase in the probability of achieving mRS 0–2 required a decrease in infarct volume of approximately 34.0 mL (95% confidence interval: -32.5 to -35.6). At infarct volumes above 250 mL, the probability of achieving mRS 0–2 probability was near zero. The relationships of tissue-specific infarct volumes and parenchymal hemorrhage volume generally showed similar patterns, although variability was high. Conclusion There seems to be a near-linear association between total infarct volume and probability of achieving good outcome for infarcts up to 250 mL, whereas patients with infarct volumes greater than 250 mL are highly unlikely to have a favorable outcome.

Background and Purpose Infarcts in acute ischemic stroke (AIS) patients may continue to grow even after reperfusion, due to mechanisms such as microvascular obstruction and reperfusion injury. We investigated whether and how much infarcts grow in AIS patients after near-complete (expanded Thrombolysis in Cerebral Infarction [eTICI] 2c/3) reperfusion following endovascular treatment (EVT), and to assess the association of post-reperfusion infarct growth with clinical outcomes. Methods Data are from a single-center retrospective observational cohort study that included AIS patients undergoing EVT with near-complete reperfusion who received diffusion-weighted magnetic resonance imaging (MRI) within 2 hours post-EVT and 24 hours after EVT. Association of infarct growth between 2 and 24 hours post-EVT and 24-hour National Institutes of Health Stroke Scale (NIHSS) as well as 90-day modified Rankin Scale score was assessed using multivariable logistic regression. Results Ninety-four of 155 (60.6%) patients achieved eTICI 2c/3 and were included in the analysis. Eighty of these 94 (85.1%) patients showed infarct growth between 2 and 24 hours post-reperfusion. Infarct growth ≥5 mL was seen in 39/94 (41.5%) patients, and infarct growth ≥10 mL was seen in 20/94 (21.3%) patients. Median infarct growth between 2 and 24 hours post-reperfusion was 4.5 mL (interquartile range: 0.4–9.2 mL). Post-reperfusion infarct growth was associated with the 24-hour NIHSS in multivariable analysis (odds ratio: 1.16 [95% confidence interval 1.09–1.24], P

Abstract Background The conventional treatments for non-acute subdural hematoma (SDH) are facing the challenge of high hematoma recurrence and progression. A novel treatment of middle meningeal artery (MMA) embolization showed the potential role in decreasing the recurrence and progression rate of SDH compared to conventional treatments in multiple cohort studies. A randomized controlled trial is warranted to determine the effectiveness and safety of MMA embolization for non-acute hematoma and whether MMA embolization is superior to conventional treatments to lower the symptomatic recurrence and progression rate of non-acute SDH. Methods This is an investigator-initiated, multi-center, prospective, open-label parallel group trial with blinded outcome assessment (PROBE design) assessing superiority of MMA embolization compared to conventional treatments. A total of 722 patients are planned to be randomized 1:1 to receive MMA embolization (intervention) or conventional treatments (control). The primary outcome is the symptomatic SDH recurrence/progression rate within 90 ± 14 days post-randomization. Discussion This trial will clarify whether MMA embolization could reduce the recurrence or progression rate of symptomatic non-acute SDH compared to conventional treatment. Trial registration ClinicalTrials.gov. Identifier: NCT04700345, Registered on 7 January 2021.

Background Nerinetide treatment was associated with better clinical outcomes among patients with stroke undergoing endovascular treatment who were not treated with concurrent alteplase in the randomized ESCAPE‐NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) trial. In patients receiving alteplase, no such effect was seen due to an inactivation of nerinetide by plasmin – the product of tissue plasminogen activation. We hypothesized that improved outcomes in the no‐alteplase patients were associated with reduced infarct growth, a radiological correlate of improved stroke outcomes. Methods Data are from the no‐alteplase stratum of the ESCAPE‐NA1 trial. Patients who underwent computer tomography perfusion (CTP) as part of routine clinical care were included. Admission CTP source data were processed using RAPID software. Infarct core at baseline was defined as areas of relative cerebral blood flow

There are several controversies regarding the role of sex and gender in the pathophysiology and management of acute stroke. Assessing the role of sex, i.e., biological/pathophysiological factors, and gender, i.e., sociocultural factors, in isolation is often not possible since they are closely intertwined with each other. To complicate matters even more, the functional baseline status of women and men at the time of their first stroke is substantially different, whereby women have, on average, a poorer reported/ascertained baseline function compared to men. These differences in baseline variables account for a large part of the differences in post-stroke outcomes between women and men. Adjusting for these baseline differences is difficult, and in many cases, residual confounding cannot be excluded. Despite these obstacles, a better understanding of how patient sex and gender differences influence acute stroke and stroke care pathways is crucial to avoid biases and allow us to provide the best possible care for all acute stroke patients. Disregarding patient sex and gender on one hand and ignoring potential confounding factors in sex- and gender-stratified analyses on the other hand, may cause researchers to come to erroneous conclusions and physicians to provide suboptimal care. This review outlines sex- and gender-related factors in key aspects of acute stroke, including acute stroke epidemiology, diagnosis, access to care, treatment outcomes, and post-acute care. We also attempt to outline knowledge gaps, which deserve to be studied in further detail, and practical implications for physicians treating acute stroke patients in their daily practice.

Multicentric fibrolamellar hepatocellular carcinoma has not been reported yet in the world as of our knowledge. A Medline search for the term “multicentric fibrolamellar HCC” did not return any results. To our knowledge, this is the first case report of multi-centric fibrolamellar hepatocellular carcinoma (HCC). We present the case of a 22-year-old male patient who had complaints of epigastric pain for 1 month. His general physical examinations were normal. Computed tomography of the abdomen revealed multiple hyper-enhancing space-occupying lesions, one of which showed a central scar. The final diagnosis of the case was multicentric fibrolamellar HCC, which was biopsy proven.

Background The optimal management of patients with symptomatic isolated internal carotid artery (ICA) occlusion is unknown. We aimed to assess whether endovascular treatment (EVT) compared with standard medical care was associated with improved functional outcomes in patients with acute symptomatic isolated intracranial ICA occlusion without involvement of the middle or anterior cerebral artery, that is, ICA‐I occlusion. Additionally, we aimed to compare ICA‐I with ICA‐L/T occlusion, which involves themiddle and anterior cerebral artery, respectively. Methods We analyzed data from the highly effective reperfusion evaluated in multiple endovascular stroke trials (HERMES) collaboration, which performed an individual patient data meta‐analysis of 7 randomized controlled trials conducted between 2010 and 2017 assessing the benefit of EVT compared to medical management in patients with anterior circulation large vessel occlusion. We assessed the association between EVT and 90‐day good functional outcome (modified Rankin scale scores 0–2), National Institutes of Health Stroke Scale scores at 24 hours, symptomatic intracranial hemorrhage rates and mortality in patients with ICA‐I and ICA‐L/T occlusion. Results We included 442 patients with intracranial ICA occlusion, of whom 38 (8.6%) had ICA‐I occlusion. In the ICA‐I group, the median age [interquartile range] was 69.5 [61.7–79.5] years, 42.1% were male, and median baseline National Institutes of Health Stroke Scale was 17 [15–20]. Compared with standard medical care alone, EVT resulted in higher good outcome rates in patients with ICA‐I (42.9% versus 25%; P=0.296) and ICA‐L/T occlusion (32.5% versus 14.4%; P

Background First‐pass effect (FPE), that is, achieving reperfusion with a single thrombectomy device pass, is associated with better clinical outcomes in patients with acute stroke. FPE is therefore increasingly used as a marker of device and procedural efficacy. We aimed to evaluate the ability of thrombus‐based radiomics models to predict FPE in patients undergoing endovascular thrombectomy and compare performance with experts and nonradiomics thrombus characteristics. Methods Patients with thin‐slice noncontrast computed tomography and computed tomography angiography from the ESCAPE‐NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) trial were included. Thrombi were manually segmented on all images. Data were randomly split into a derivation set that included a training and a validation subset and an independent test set. Radiomics features were extracted from the derivation set. The machine learning models were compared with 3 expert stroke physicians in predicting FPE in the test set using area under the receiver operating characteristic curves. Results Thin‐slice images of 554 patients were divided into a derivation set (training [n=388] and validation [n=55]) and a test set (n=111). A radiomics model using the combination of noncontrast computed tomography, computed tomography angiography, and noncontrast computed tomography–computed tomography angiography difference achieved the highest performance (area under the curve, 0.74 [95% CI, 0.64–0.84]) for prediction of FPE. This was higher than the mean area under the curve of the 3 experts (0.62 [95% CI, 0.53–0.71], P=0.01 for difference in area under the curves). The radiomics model also performed better than nonradiomics‐based thrombus features such as volume and permeability measurements in predicting FPE (P

Background Patients with white matter disease (WMD) – a key marker of cerebral small vessel disease – may have less brain reserve to cope with ischemic injury. The relationship of WMD to functional recovery after endovascular thrombectomy is uncertain. We aim to explore the association between WMD and functional outcome, assessed at multiple time‐points postendovascular thrombectomy. Methods In this post hoc analysis, we analyzed noncontrast computed tomography‐imaging from the ESCAPE‐NA1 (Safety and Efficacy of Nerinetide [NA‐1] in Subjects Undergoing Endovascular Thrombectomy for Stroke) trial and assessed WMD by using the total Fazekas‐score (score range: 0–6). The primary outcome was repeated measurements of the modified Rankin scale (mRS) scores (i.e., day‐5/discharge, day‐30, and day‐90). Secondary outcome measures were the ordinal‐mRS at 90‐days, 90‐day‐mRS0–2, and 90‐day‐mortality. Mixed‐linear and binary/ordinal logistic regressions were performed, adjusting for age, sex, baseline National Institutes of Health Stroke Scale, cortical atrophy, chronic infarctions, stroke laterality, follow‐up infarct volume, and alteplase–nerinetide interaction. Sensitivity analyses were done including only those patients for whom magnetic resonance imaging was available. Results We included 1102 patients with noncontrast computed tomography (median age 71, interquartile range: 61–80; median National Institutes of Health Stroke Scale 17, interquartile range: 12–21). The median total Fazekas‐score was 1(interquartile range: 0–2). Out of 1202 patients, 566 had follow‐up magnetic resonance imaging. We observed heterogeneity in functional recovery with varying degrees of WMD‐burden (P

Abstract Background Although endovascular therapy (EVT) improves clinical outcomes in patients with acute ischemic stroke, the time of EVT initiation significantly influences clinical outcomes and healthcare costs. This study evaluated the impact of EVT treatment delay on cost-effectiveness in China. Methods A model combining a short-term decision tree and long-term Markov health state transition matrix was constructed. For each time window of symptom onset to EVT, the probability of receiving EVT or non-EVT treatment was varied, thereby varying clinical outcomes and healthcare costs. Clinical outcomes and cost data were derived from clinical trials and literature. Incremental cost-effectiveness ratio and incremental net monetary benefits were simulated. Deterministic and probabilistic sensitivity analyses were performed to assess the robustness of the model. The willingness-to-pay threshold per quality-adjusted life-year (QALY) was set to ¥71,000 ($10,281). Results EVT performed between 61 and 120 min after the stroke onset was most cost-effective comparing to other time windows to perform EVT among AIS patients in China, with an ICER of ¥16,409/QALY ($2376) for performing EVT at 61–120 min versus the time window of 301–360 min. Each hour delay in EVT resulted in an average loss of 0.45 QALYs and 165.02 healthy days, with an average net monetary loss of ¥15,105 ($2187). Conclusions Earlier treatment of acute ischemic stroke patients with EVT in China increases lifetime QALYs and the economic value of care without any net increase in lifetime costs. Thus, healthcare policies should aim to improve efficiency of pre-hospital and in-hospital workflow processes to reduce the onset-to-puncture duration in China.

Randomized controlled trials (RCT) are the basis for evidence-based acute stroke care. For an RCT to change practice, its results have to be statistically significant and clinically meaningful. While methods to assess statistical significance are standardized and widely agreed upon, there is no clear consensus on how to assess clinical significance. Researchers often refer to the minimal clinically important difference (MCID) when describing the smallest change in outcomes that is considered meaningful to patients and leads to a change in patient management. It is widely accepted that a treatment should only be adopted when its effect on outcome is equal to or larger than the MCID. There are however situations in which it is reasonable to decide against adopting a treatment, even when its beneficial effect matches or exceeds the MCID, for example when it is resource-intensive and associated with high costs. Furthermore, while the MCID represents an important concept in this regard, defining it for an individual trial is difficult as it is highly context specific. In the following, we use hypothetical stroke trial examples to review the challenges related to MCID, sample size and pragmatic considerations that researchers face in acute stroke trials, and propose a framework for designing meaningful stroke trials that have the potential to change clinical practice.

Abstract Background The occurrence of invasive fungal infections in COVID-19 patients is on surge in countries like India. Several reports related to rhino-nasal-sinus mucormycosis in COVID patients have been published in recent times; however, very less has been reported about invasive pulmonary fungal infections caused mainly by mucor, aspergillus or invasive candida species. We aimed to present 6 sputum culture proved cases of invasive pulmonary fungal infection (four mucormycosis and two invasive candidiasis) in COVID patients, the clues for the diagnosis of fungal invasion as well as difficulties in diagnosing it due to superimposed COVID imaging features. Case presentation The HRCT imaging features of the all 6 patients showed signs of fungal invasion in the form of cavities formation in the pre-existing reverse halo lesions or development of new irregular margined soft tissue attenuating growth within the pre-existing or in newly formed cavities. Five out of six patients were diabetics. Cavities in cases 1, 2, 3 and 4 of mucormycosis were aggressive and relatively larger and showed relatively faster progression into cavities in comparison with cases 5 and 6 of invasive candidiasis. Conclusion In poorly managed diabetics or with other immunosuppressed conditions, invasive fungal infection (mucormycosis, invasive aspergillosis and invasive candidiasis) should be considered in the differential diagnosis of cavitary lung lesions.

Background: In this coronavirus disease-2019 (COVID-19) pandemic, safe and effective preventative vaccines are essential to contain the pandemic, which has had severe medical, economic, and societal consequences, despite some people still becoming infected after receiving immunisation. Methods: A total of 200 patients were examined and split into two groups: (1) 100 consecutive COVID-19-positive cases who had been vaccinated and (2) 100 consecutive COVID-19-positive patients with no vaccination. At the time of the scan, the patient's vaccination status was noted. Results: The computed tomography severity score (CTSS) of unvaccinated individuals was found to be considerably greater than that of partly or fully vaccinated patients (median 13 vs. 7, P < 0.001). Completely vaccinated individuals had a considerably lower median CTSS than partly vaccinated patients (6 vs. 9, P < 0.001). Conclusions: Individuals should be thoroughly vaccinated to avoid major lung disease. As a result, stronger dedication and motivating efforts should be made worldwide to improve the COVID-19 vaccination program.

Barotrauma has many different presentations, including pneumothorax, subcutaneous emphysema, pneumoperitoneum, and pneumomediastinum. We have presented and analyzed some interesting cases of barotrauma in this case series. Case 1 in our series developed a thin-walled new cavity due to barotrauma, mimicking pneumatocele and fungal cavity. Case 2 presented with coexistence of pneumothorax and cavity with fungal infestation. Severity of barotrauma due to positive pressure ventilation has been shown in case 3. An interesting case of barotrauma in a 36-week primigravida, post cesarean section, causing dehiscence of scar, presented as case 4 in our series. Early and rapid imaging diagnosis of barotrauma should be pursued. In patients with mechanical ventilation, identifying small changes in imaging characteristics of cavitary lesions, such as fungal, bacterial, or transient cavities, would aid physicians in offering a correct treatment plan.

Introduction Endovascular therapy (EVT) is the standard‐of‐care for large vessel occlusion stroke; however, timely access to treatment is still limited for a large proportion of the population. Telerobotic EVT has the potential to decrease time to treatment and expand existing networks of care to more rural populations. It is currently unclear how its implementation would impact existing stroke networks. Methods Conditional probability models were generated to predict the probability of excellent outcome (modified Rankin Scale 0–1 at 90 days post stroke) for patients with suspected large vessel occlusion (LVO). A baseline stroke network was created for California using existing intravenous thrombolysis (IVT) centers and comprehensive stroke centers (CSCs) capable of IVT and EVT. Optimal transport decisions and catchment areas were generated for the baseline model and three hypothetical scenarios through conversion of IVT centers at various distances from a CSC into centers capable of Telerobotic EVT [i.e. hospitals ≥ 15 and < 50 miles from a CSC were converted (Scenario 1), ≥ 50 and < 100 miles (Scenario 2), and ≥ 100 miles (Scenario 3)]. Catchment areas were calculated for each scenario using varied robotic procedural delay times and success rates. Results In the baseline model, 51 hospitals were designated as CSCs and 142 hospitals were designated IVT centers. Conversion of IVT centers into Telerobotic EVT centers decreased median travel time for LVO patients in all three scenarios. The estimated number of robotically treated LVOs per year in Scenarios 1, 2, and 3 were 2172, 740, and 212, respectively. Scenario 1 (15‐50 miles) was the most sensitive to robotic time delay and success rate, but all three scenarios were more sensitive to decreases in procedural success rate compared to time delay. Conclusions Telerobotic EVT has the potential to improve care for stroke patients outside of major urban centers. Compared to procedural time delays in robotic EVT, a decrease in procedural success rate would not be well tolerated. This modeling analysis can inform system planning for the potential advent of remote EVT care.

Introduction The current neurovascular research funding environment is highly competitive, stifling collaboration and hindering progress. Further, specific groups of researchers/research topics are disproportionately affected, resulting in inequity in the funding process. These include early‐career researchers, women, and researchers from low‐middle income countries. Certain conditions, e.g., rare, stroke‐related diseases are due to their low prevalence not suitable for clinical trials, and therefore even less likely to receive funding. Currently, there is no easy way for people working on such topics to come together and collaborate. To address this problem, a novel internet‐based platform, Collavidence (www.collavidence.com), was designed. The idea is to complement current systems of neurovascular research collaboration and funding for more inclusive, efficient, and impactful research results. The aim of this study is to present the initial performance of the platform in achieving this goal. Methods Analytics on pre‐defined user‐, project‐, and interaction‐based metrics will be performed to describe the level of platform engagement in the initial months following launch. These include the number of users and projects posted, the amount of funding accumulated, the proportion of successfully funded projects, and the iterative improvement of the proposals. Further, the relative engagement of early‐career, female researchers, and researchers from low‐middle‐income countries will be assessed. Results A qualitative assessment of the value of the overall platform, the process of iterative review, and possibilities for collaboration will be presented. Further, trends in platform engagement during the initial 3 months, including the relative distribution of specific user demographics to assess the platform’s success in encouraging equity, diversity, and inclusion, will be presented. Conclusions This study will assess the feasibility and initial success of Collavidence as a unique platform for neurovascular research collaboration and funding.

Restoring blood flow to brain tissue at risk of infarction is essential for tissue survival and clinical outcome. We used cerebral blood flow (CBF) quantified with multiple post-labeling delay (PLD) pseudocontinuous arterial spin labeling (ASL) MRI after ischemic stroke and assessed the association between CBF and early neurological outcome. We acquired ASL with 7 PLDs at 3.0 T in large vessel occlusion stroke patients at 24 h. We quantified CBF relative to the contralateral hemisphere (rCBF) and defined hyperperfusion as a ≥30% increase and hypoperfusion as a ≥40% decrease in rCBF. We included 44 patients (median age: 70 years, median NIHSS: 13, 40 treated with endovascular thrombectomy) of whom 37 were recanalized. Hyperperfusion in ischemic core occurred in recanalized but not in non-recanalized patients (65.8% vs 0%, p = 0.006). Hypoperfusion occurred only in the latter group (0% vs 85.7%, p

Background Current stroke guidelines recommend advanced imaging (computed tomography [CT] perfusion or magnetic resonance imaging) prior to endovascular therapy (EVT) in patients with late presentation of large vessel occlusion. Adherence to guidelines may be constrained by resources or timely access to imaging. We sought to understand the factors which influence late window imaging selection for EVT candidates with large vessel occlusion. Methods We conducted an international survey from January to May 2022. The questions aimed to identify advanced imaging and treatment decisions based on access to imaging, time delays, and simulated patient scenarios. Results There were 3000 invited participants and 1506 respondents, the majority (89.6%) from comprehensive stroke centers in high‐income countries. Neurointerventionalists comprised 31.8% and noninterventionalists 68.2% of respondents. Overall, 70.7% reported routine use of advanced imaging for late EVT selection, and 63.6% reported its usage in every case. There was greater availability of advanced imaging in comprehensive stroke centers versus primary stroke centers (67.0% versus 33.7%; P

Abstract Background High-resolution computed tomography (HRCT) chest becomes a valuable diagnostic tool for identifying patients infected with Coronavirus Disease 2019 (COVID-19) in the early stage, where patients may be asymptomatic or with non-specific pulmonary symptoms. An early diagnosis of COVID-19 is of utmost importance, so that patients can be isolated and treated in time, eventually preventing spread of the disease, improving the prognosis and reducing the mortality. In this paper, we have highlighted our radiological experience of dealing with the pandemic crisis of 2020 through the study of HRCT thorax, lung ultrasonography, chest X-rays and artificial intelligence (AI). Results Results of CT thorax analysis have been given in detail. We had also compared CT severity score (CTSS) with clinical and laboratory parameters. Correlation of CTSS with SpO2 values and comorbidities was also studied. We also analysed manual CTSS with the CTSS scored calculated by the AI software. Conclusions CTSS and use of COVID-19 Reporting and Data System (CORADS) result in accuracy and uniform percolation of information among the clinicians. Bed-side X-rays and ultrasonography have played a role where the patients could not be shifted for CT scan. The possibility of predicting impending or progression of hypoxia was not possible when SpO2 mapping was correlated with the CTSS. AI was alternatively tried with available software (CT pneumonia analysis) which was not so appropriate considering the imaging patterns in the bulk of atypical category.

Background Although the association between cortical venous opacification (VO) and clinical outcomes has been shown in previous studies, little is known about the relationship between parenchymal hemorrhage (PH) and VO in patients with acute stroke. We aimed to determine whether cortical VO assessed on computed tomography angiography correlates with the risk of PH following endovascular treatment. Methods This is a post hoc analysis of the ESCAPE NA‐1 (Efficacy and Safety of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke) trial. Control‐arm patients with adequate venous assessment on computed tomography angiography were included. Any PH and symptomatic intracranial hemorrhage were compared between patients with poor VO (cortical vein opacification score

Background and Purpose Various imaging paradigms are used for endovascular treatment (EVT) decision-making and outcome estimation in acute ischemic stroke (AIS). We aim to compare how these imaging paradigms perform for EVT patient selection and outcome estimation. Methods Prospective multi-center cohort study of patients with AIS symptoms with multi-phase computed tomography angiography (mCTA) and computed tomography perfusion (CTP) baseline imaging. mCTA-based EVT-eligibility was defined as presence of large vessel occlusion (LVO) and moderate-to-good collaterals on mCTA. CTP-based eligibility was defined as presence of LVO, ischemic core (defined on relative cerebral blood flow, absolute cerebral blood flow, and cerebral blood volume maps) 1.8, absolute mismatch >15 mL. EVT-eligibility and adjusted rates of good outcome (modified Rankin Scale 0–2) based on these imaging paradigms were compared. Results Of 289/464 patients with LVO, 263 (91%) were EVT-eligible by mCTA-criteria versus 63 (22%), 19 (7%) and 103 (36%) by rCBF, aCBF, and CBV-CTP-criteria. CTP and mCTA-criteria were discordant in 40% to 53%. Estimated outcomes were best in patients who met both mCTA and CTP eligibility-criteria and were treated with EVT (62% to 87% good outcome). Patients eligible for EVT by mCTA-criteria and not by CTP-criteria receiving EVT achieved good outcome rates of 53% to 57%. Few patients met CTP-criteria and not mCTA-criteria for EVT. Conclusions Simpler imaging selection criteria that rely on little else than detection of the occluded blood vessel may be more sensitive and less specific, thus resulting in more patients being offered EVT and arguably benefiting from it.

Background and Purpose Multiphase computed tomographic angiography (mCTA) provides time variant images of pial vasculature supplying brain in patients with acute ischemic stroke (AIS). To develop a machine learning (ML) technique to predict tissue perfusion and infarction from mCTA source images. Methods 284 patients with AIS were included from the Precise and Rapid assessment of collaterals using multi-phase CTA in the triage of patients with acute ischemic stroke for Intra-artery Therapy (Prove-IT) study. All patients had non-contrast computed tomography, mCTA, and computed tomographic perfusion (CTP) at baseline and follow-up magnetic resonance imaging/non-contrast-enhanced computed tomography. Of the 284 patient images, 140 patient images were randomly selected to train and validate three ML models to predict a pre-defined Tmax thresholded perfusion abnormality, core and penumbra on CTP. The remaining 144 patient images were used to test the ML models. The predicted perfusion, core and penumbra lesions from ML models were compared to CTP perfusion lesion and to follow-up infarct using Bland-Altman plots, concordance correlation coefficient (CCC), intra-class correlation coefficient (ICC), and Dice similarity coefficient. Results Mean difference between the mCTA predicted perfusion volume and CTP perfusion volume was 4.6 mL (limit of agreement [LoA], –53 to 62.1 mL; P=0.56; CCC 0.63 [95% confidence interval [CI], 0.53 to 0.71; P

Background The best management of basilar artery occlusion (BAO) remains uncertain. The BASICS (Basilar Artery International Cooperation Study) and the BEST (Basilar Artery Occlusion Endovascular Intervention Versus Standard Medical Treatment) trials reported neutral results. We sought to understand physicians’ approaches to BAOs and whether further BAO randomized controlled trials were warranted. Methods We conducted an online international survey from January to March 2022 to stroke neurologists and neurointerventionalists. Survey questions were designed to examine clinical and imaging parameters under which clinicians would offer (or rescind) a patient with BAO to endovascular therapy (EVT) or best medical management versus enrollment into a randomized clinical trial. Results Of >3002 invited participants, 1245 responded (41.4% response rate) from 73 countries, including 54.7% stroke neurologists and 43.6% neurointerventionalists. More than 95% of respondents would offer EVT to patients with BAO, albeit in various clinical circumstances. There were 70.0% of respondents who indicated that the BASICS and BEST trials did not change their practice. Only 22.1% of respondents would perform EVT according to anterior circulation occlusion criteria. The selection of patients for BAO EVT by clinical severity, timing, and imaging modality differed according to geography, specialty, and country income level. Over 80% of respondents agreed that further randomized clinical trials for BAO were warranted. Moreover, 45.6% of respondents indicated they would find it acceptable to enroll all trial‐eligible patients into the medical arm of a BAO trial, whereas 26.3% would not enroll. Conclusion Most stroke physicians continue to believe in the efficacy of EVT in selected patients with BAO in spite of BEST and BASICS. There is no consensus on which selection criteria to use, and few clinicians would use anterior circulation occlusion criteria for BAOs. Further randomized clinical trials for BAO are warranted.

Purpose: The clinical significance of iatrogenic diffusion-weighted imaging lesions following endovascular procedures is currently not well understood, partly because they do not result in immediate clinical deficits (“silent brain infarcts” [SBI]) and often remain undiagnosed. Conversely, access site complications are well-documented. With the SILENT survey, we sought to gain an understanding of physicians' opinions regarding the relative importance of SBI compared to the more commonly discussed access site complications. Methods: Seven scenarios of access site complications of varying severity were provided. Within each scenario, participants were asked whether they would choose the access site complication or an increasing number of periprocedural SBI. Logistic regression clustered by respondent was performed to assess participant and scenario factors associated with preferential choice of SBI versus access site complications. Results: 67 participants (13 women; 19.4%) provided 469 responses to the survey. The majority (45; 67.2%) were neurointerventionalists. Regardless of scenario, any number of SBI was deemed unacceptable in 42.4% of cases, whereas 10.5% of physicians would accept >15 SBI to avoid any access site complications. Significant group differences for career stage (p=0.001) and specialty (p=0.007) for the number of tolerated SBI were observed. Regression analyses revealed that only hematoma severity was significantly associated with the willingness to accept an increasing number of SBI. Conclusion: In this survey, 4/10 physicians would accept even severe access site complications to avoid any SBI. The perceived importance of SBI among experienced physicians, and the uncertainty regarding their long-term sequelae, support their systematic assessment and reporting.

Objectives We sought to determine the predictors of 90-day mortality despite successful reperfusion.Design Subgroup analysis of a multicentre randomised clinical trial (ClinicalTrials.gov Identifier: NCT03469206).Setting This study used data from the Direct Intra-arterial thrombectomy in order to Revascularize AIS patients with large vessel occlusion Efficiently in Chinese Tertiary hospitals: a Multicenter randomized clinical Trial (DIRECT-MT).Participants 622 patients enrolled in DIRECT-MT.Results Overall successful reperfusion rate was 82.0% (510/622), and 18.5% (115/622) of patients died within 90 days. Univariate analysis identified increased risks of mortality for age ≥70 years, history of diabetes mellitus, National Institutes of Health Stroke Scale (NIHSS) score on admission ≥17, NIHSS score after thrombectomy (24±6 hours) ≥11, Alberta Stroke Program Early Computed Tomography Score (ASPECTS)

Background Statistical models to predict outcomes after endovascular therapy for acute ischemic stroke often incorporate baseline (pretreatment) variables only. We assessed the performance of stroke outcome prediction models for endovascular therapy in stroke in an iterative fashion using baseline, treatment‐related, and posttreatment variables. Methods Data from the ESCAPE‐NA1 (Safety and Efficacy of Nerinetide [NA‐1] in Subjects Undergoing Endovascular Thrombectomy for Stroke) trial were used to build 4 outcome prediction models using multivariable logistic regression: model 1 included baseline variables available before treatment decision making, model 2 included additional treatment‐related variables, model 3 additional posttreatment variables that become available early (within 24–48 hours), and model 4 later (beyond 48 hours) after endovascular therapy. The primary outcome was functional independence (90‐day Modified Rankin Scale score 0–2). Model performance was compared using the area under the receiver operating characteristic curve (AUC). Shapley values were used to determine marginal contributions of variables to outcome variance in the regression models. Results Among 1105 patients, functional independence was achieved by 666 (60.3%). When using baseline variables only (model 1), the AUC was 0.74 (95% CI, 0.71–0.77); this iteratively improved when treatment and posttreatment variables were added to the models (model 2: AUC, 0.77; 95% CI, 0.74–0.80; model 3: AUC, 0.80; 95% CI, 0.77–0.83; model 4: AUC, 0.82; 95% CI, 0.79–0.85). With baseline variables alone, 26% of patients who achieved functional independence were erroneously classified as not achieving functional independence. Even with the most comprehensive model, 19.8% of patients were misclassified as such. Patient age contributed most to outcome variance (Shapley value, 0.28), followed by severe adverse events including pneumonia (0.16) and intracranial hemorrhage at 24‐hours imaging (0.13). Conclusions A substantial contribution to outcomes after endovascular therapy comes from factors unrelated to currently collected baseline patient variables. One‐fifth of patients achieving functional independence were misclassified as not achieving independence, even with the most comprehensive model. Our findings suggest that the achievable accuracy of current outcome prediction models is limited, and caution should be used when applying them in clinical practice.

The benefit of acute ischemic stroke (AIS) treatment is highly time dependent. Although studies on workflow improvement in AIS are increasingly gaining attention, there is a lack of consensus and consistency regarding the definition, measurement, and reporting of AIS workflow times. We discuss the challenges related to defining and measuring workflow times in AIS and propose a basic set of time intervals that should be reported in AIS workflow studies. We particularly focus on patients undergoing mechanical thrombectomy. Importantly, endovascular treatment workflow times should always be reported in conjunction with reperfusion quality because one is not informative without the other. We further suggest standardized reporting of workflow times that includes the 90th percentile in addition to medians and interquartile ranges, means, and SDs. The proposed methodology serves as a framework for AIS studies and aids further discussion on workflow‐related AIS research.

Background: Endovascular treatment (EVT) for stroke due to medium vessel occlusion (MeVO) can be technically challenging. Devices and tools are rapidly evolving. We aimed to gain insight into preferences and global perspectives on the usage of endovascular tools in treating MeVOs.Methods: We conducted an international survey with seven scenarios of patients presenting A3, M2/3, M3, M3/4, or P2/3 occlusions. Respondents were asked for their preferred first-line endovascular approach, and whether they felt that the appropriate endovascular tools were available to them. Answers were analyzed by occlusion location and geographical region of practice, using multinomial/binary logistic regression.Results: A total of 263 neurointerventionists provided 1836 responses. The first-line preferences of physicians were evenly distributed among stent-retrievers, combined approaches, and aspiration only (33.2, 29.8, and 26.8%, respectively). A3 occlusions were more often treated with stent-retrievers (RR 1.21, 95% CI: 1.07–1.36), while intra-arterial thrombolysis was more often preferred in M3 (RR 2.47, 95% CI: 1.53–3.98) and M3/4 occlusions (RR 7.71, 95% CI: 4.16–14.28) compared to M2/3 occlusions. Respondents who thought appropriate tools are currently not available more often chose stent retrievers alone (RR 2.07; 95% CI: 1.01–4.24) or intra-arterial thrombolysis (RR 3.35, 95% CI: 1.26–8.42). Physicians who stated that they do not have access to optimal tools opted more often not to treat at all (RR 3.41, 95% CI: 1.11–10.49). Stent-retrievers alone were chosen more often and contact aspiration alone less often as a first-line approach in Europe (RR 2.12, 95% CI: 1.38–3.24; and RR 0.49, 95% CI 0.34–0.70, respectively) compared to the United States and Canada.Conclusions: In EVT for MeVO strokes, neurointerventionalists choose a targeted vessel specific first-line approach depending on the occlusion location, region of practice, and availability of the appropriate tools.

Detecting medium vessel occlusions (MeVOs) is often challenging due to their distal location and small vessel size. Herein we describe an innovative imaging technique for fast and reliable MeVO detection: time-variant color-coded multiphase CTA. Three CTA phases of the intracranial vasculature are color-coded and displayed in a single summation image, which improves visualization of MeVOs through a color indicator effect, thereby substantially facilitating MeVO detection, particularly for readers with limited experience.

Background and Purpose: During the months and years post-stroke, treatment benefits from endovascular therapy (EVT) may be magnified by disability-related differences in morbidity/mortality or may be eroded by recurrent strokes and non-stroke-related disability/mortality. Understanding the extent to which EVT benefits may be sustained at 5 years, and the factors influencing this outcome, may help us better promote the sustenance of EVT benefits until 5 years post-stroke and beyond.Methods: In this review, undertaken 5 years after EVT became the standard of care, we searched PubMed and EMBASE to examine the current state of the literature on 5-year post-stroke outcomes, with particular attention to modifiable factors that influence outcomes between 3 months and 5 years post-EVT.Results: Prospective cohorts and follow-up data from EVT trials indicate that 3-month EVT benefits will likely translate into lower 5-year disability, mortality, institutionalization, and care costs and higher quality of life. However, these group-level data by no means guarantee maintenance of 3-month benefits for individual patients. We identify factors and associated “action items” for stroke teams/systems at three specific levels (medical care, individual psychosocioeconomic, and larger societal/environmental levels) that influence the long-term EVT outcome of a patient. Medical action items include optimizing stroke rehabilitation, clinical follow-up, secondary stroke prevention, infection prevention/control, and post-stroke depression care. Psychosocioeconomic aspects include addressing access to primary care, specialist clinics, and rehabilitation; affordability of healthy lifestyle choices and preventative therapies; and optimization of family/social support and return-to-work options. High-level societal efforts include improving accessibility of public/private spaces and transportation, empowering/engaging persons with disability in society, and investing in treatments/technologies to mitigate consequences of post-stroke disability.Conclusions: In the longtime horizon from 3 months to 5 years, several factors in the medical and societal spheres could negate EVT benefits. However, many factors can be leveraged to preserve or magnify treatment benefits, with opportunities to share responsibility with widening circles of care around the patient.

Background: Clinical stroke rehabilitation decision making relies on multi-modal data, including imaging and other clinical assessments. However, most previously described methods for predicting long-term stroke outcomes do not make use of the full multi-modal data available. The aim of this work was to develop and evaluate the benefit of nested regression models that utilise clinical assessments as well as image-based biomarkers to model 30-day NIHSS.Method: 221 subjects were pooled from two prospective trials with follow-up MRI or CT scans, and NIHSS assessed at baseline, as well as 48-hours and 30 days after symptom onset. Three prediction models for 30-day NIHSS were developed using a support vector regression model: one clinical model based on modifiable and non-modifiable risk factors (MCLINICAL) and two nested regression models that aggregate clinical and image-based features that differed with respect to the method used for selection of important brain regions for the modelling task. The first model used the widely accepted RreliefF (MRELIEF) machine learning method for this purpose, while the second model employed a lesion-symptom mapping technique (MLSM) often used in neuroscience to investigate structure-function relationships and identify eloquent regions in the brain.Results: The two nested models achieved a similar performance while considerably outperforming the clinical model. However, MRELIEF required fewer brain regions and achieved a lower mean absolute error than MLSM while being less computationally expensive.Conclusion: Aggregating clinical and imaging information leads to considerably better outcome prediction models. While lesion-symptom mapping is a useful tool to investigate structure-function relationships of the brain, it does not lead to better outcome predictions compared to a simple data-driven feature selection approach, which is less computationally expensive and easier to implement.

Infarct volume (FIV) on follow-up diffusion-weighted imaging (FU-DWI) is only moderately associated with functional outcome in acute ischemic stroke patients. However, FU-DWI may contain other imaging biomarkers that could aid in improving outcome prediction models for acute ischemic stroke. We included FU-DWI data from the HERMES, ISLES, and MR CLEAN-NO IV databases. Lesions were segmented using a deep learning model trained on the HERMES and ISLES datasets. We assessed the performance of three classifiers in predicting functional independence for the MR CLEAN-NO IV trial cohort based on: (1) FIV alone, (2) the most important features obtained from a trained convolutional autoencoder (CAE), and (3) radiomics. Furthermore, we investigated feature importance in the radiomic-feature-based model. For outcome prediction, we included 206 patients: 144 scans were included in the training set, 21 in the validation set, and 41 in the test set. The classifiers that included the CAE and the radiomic features showed AUC values of 0.88 and 0.81, respectively, while the model based on FIV had an AUC of 0.79. This difference was not found to be statistically significant. Feature importance results showed that lesion intensity heterogeneity received more weight than lesion volume in outcome prediction. This study suggests that predictions of functional outcome should not be based on FIV alone and that FU-DWI images capture additional prognostic information.

Introduction: An early diagnosis of Coronavirus Disease (COVID19) is of utmost importance, so that patients can be isolated and treated in time, eventually preventing spread of the disease, improving the prognosis and reducing the mortality. High Resolution Computed Tomography (HRCT) chest imaging and Artificial Intelligence (AI) driven analysis of HRCT chest images can play a vital role in management of COVID-19 patients. Aim: To explore the various HRCT chest findings in different phases of COVID-19 pneumonia and to assess the potential role of AI in quantitative assessment of lung parenchymal involvement in COVID-19 pneumonia. Materials and Methods: The present retrospective observational study which was conducted between 1st May 2020 to 13th August 2020. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) positive 2169 COVID-19 patients who underwent HRCT chest were included in the study. Presence and distribution of lesions like: Ground Glass Opacity (GGO), consolidation and any specific patterns like septal thickening, reverse halo, sign, etc., were noted in the HRCT images. HRCT chest findings in different phases of disease (Early: 10 days) were assessed. CT Severity Score (CTSS) was calculated based on the extent of lung involvement on HRCT, which was then correlated with the clinical severity of the disease. Artificial Intelligence powered “CT Pneumonia analysis” algorithm was used to quantify the extent of involvement of lungs by calculating Percentage of Opacity (PO) and Percentage of High Opacity (PHO) in lungs. Tests of statistical significance, like Chi-square, Analysis of Variance (ANOVA) and Posthoc tests were applied depending on the type of variables, wherever applicable. Results: Radiological findings were seen in HRCT chest of 1438 patients. Typical pattern of COVID-19 pneumonia, i.e., bilateral, peripherally located GGO with or without consolidation was seen in 846 patients. About 294 asymptomatic patients were found to be radiologically positive. HRCT chest in the early phase of disease mostly showed GGO. Features like increased reticulation, predominance of consolidation, presence of fibrous stripes indicated late phase. About 91.3% of cases having CTSS ≤7 were asymptomatic or clinically mild whereas, 81.2% cases having score ≥15 were clinically severe. The mean PO and PHO (30.1±28.0 and 8.4±10.4, respectively) were remarkably higher in clinically severe category. Conclusion: Progression of COVID-19 pneumonia is rapid, so radiologists and clinicians need to get familiarised with the typical CT chest findings, hence patients can be treated on time, eventually improving the prognosis and reducing the mortality. Artificial Intelligence has the potential to be a valuable tool in management of COVID-19 patients.

Endovascular thrombectomy (EVT) has become standard of care for large vessel occlusion strokes but current guidelines exclude a large proportion of patients from this highly effective treatment. This review therefore focuses on expanding indications for EVT in several borderline indications such as patients in the extended time window, patients with extensive signs of infarction on admission imaging, elderly patients and patients with pre-existing deficits. It also discusses the current knowledge on intravenous thrombolysis as an adjunct to EVT and EVT as primary therapy for distal vessel occlusions, for tandem occlusions, for basilar artery occlusions and in pediatric patients. We provide clear recommendations based on current guidelines and further literature.

Objectives Endovascular therapy (EVT) significantly improves clinical outcomes in patients with acute ischaemic stroke (AIS), while the time of EVT initiation after stroke onset influences both patient clinical outcomes and healthcare costs. This study determined the impact of EVT treatment delay on cost effectiveness of EVT in the Singapore healthcare setting.Design A short-term decision tree and long-term Markov health state transition model was constructed. For each time window of symptom onset to EVT, the probability of receiving EVT or non-EVT treatment was varied, thereby varying clinical outcomes (modified Rankin Scale scores), short-term costs and long-term modelled (lifetime) costs; all of which were used in calculating an incremental cost-effectiveness ratio of EVT vs non-EVT treatment. Clinical outcomes and cost data were derived from clinical trials, literature, expert opinion, electronic medical records and community-based surveys from Singapore. Deterministic one-way and probabilistic sensitivity analyses were performed to assess the uncertainty of the model. The willingness to pay for per quality-adjusted life-year (QALY) was set to Singapore $50 000 (US$36 500).Setting Singapore healthcare perspective.Participants The model included patients with AIS in Singapore.Interventions EVT performed within 6 hours of stroke onset.Outcome measures The model estimated incremental cost-effectiveness ratios (ICERs) and net monetary benefits (NMB) for EVT versus non-EVT treatment, varied by time from symptom onset to time of treatment.Results EVT performed between 61 min and 120 min after the stroke onset was most cost-effective time window to perform EVT in the Singapore population, with an ICER of Singapore $7197 per QALY (US$5254) for performing EVT at 61–120 min versus 121–180 min. The resulting incremental NMB associated with receipt of EVT at the earlier time point is Singapore $39 827 (US$29 074) per patient at the willingness-to-pay threshold of Singapore $50 000. Each hour delay in EVT resulted in an average loss of 0.54 QALYs and 195.35 healthy days, with an average net monetary loss of Singapore $26 255 (US$19 166).Conclusions From the Singapore healthcare perspective, although EVT is more expensive than alternative treatments in the short term, the lifetime ICER is below the willingness-to-pay threshold. Thus, healthcare policies and procedures should aim to improve efficiency of pre-hospital and in-hospital workflow processes to reduce the onset-to-puncture duration.

Endovascular clot retrieval, often referred to as mechanical thrombectomy, has transformed the treatment of patients with ischemic stroke based on an underlying large cerebral vessel occlusion, ranging from the extracranial internal carotid artery (ICA) to the M1 (proximal) segment of the middle cerebral artery (MCA). The aim of this study was to evaluate the effect of a progressive occlusion of the extracranial portion of the ICA on the cerebral blood flow either with a conventional guiding catheter or a balloon-guiding catheter, which enables the operator to completely occlude the parent artery by inflating the balloon around the tip of this type of guiding catheter. We evaluated the impact of flow reduction in the ICA in the setting of ipsilateral MCA occlusion given the different configurations of the circle of Willis (CoW). The computer model of cerebral arteries was based on anatomical works by Rhoton (1) and van der Eecken (2). The interactive experimental results are available on the web at https://gntem3.shinyapps.io/ecrsim. In the setting of left MCA occlusion, compensation from the anterior and posterior communicating artery preserved the flow in the left anterior cerebral artery (ACA) but not the left MCA branches. Under selected CoW configurations, such as classic, missing Acom, or missing A1 segment of the ACA and concurrent right ICA occlusion, there was a progressive decrease of flow in the left ACA to a minimum of 78% when the simulated catheter fully occluded the left ICA. Flow collapsed (

Background and Purpose: Stroke-related functional risk scores are used to predict patients' functional outcomes following a stroke event. We evaluate the predictive accuracy of machine-learning algorithms for predicting functional outcomes in acute ischemic stroke patients after endovascular treatment.Methods: Data were from the Precise and Rapid Assessment of Collaterals with Multi-phase CT Angiography (PROVE-IT), an observational study of 614 ischemic stroke patients. Regression and machine learning models, including random forest (RF), classification and regression tree (CART), C5.0 decision tree (DT), support vector machine (SVM), adaptive boost machine (ABM), least absolute shrinkage and selection operator (LASSO) logistic regression, and logistic regression models were used to train and predict the 90-day functional impairment risk, which is measured by the modified Rankin scale (mRS) score > 2. The models were internally validated using split-sample cross-validation and externally validated in the INTERRSeCT cohort study. The accuracy of these models was evaluated using the area under the receiver operating characteristic curve (AUC), Matthews Correlation Coefficient (MCC), and Brier score.Results: Of the 614 patients included in the training data, 249 (40.5%) had 90-day functional impairment (i.e., mRS > 2). The median and interquartile range (IQR) of age and baseline NIHSS scores were 77 years (IQR = 69–83) and 17 (IQR = 11–22), respectively. Both logistic regression and machine learning models had comparable predictive accuracy when validated internally (AUC range = [0.65–0.72]; MCC range = [0.29–0.42]) and externally (AUC range = [0.66–0.71]; MCC range = [0.34–0.42]).Conclusions: Machine learning algorithms and logistic regression had comparable predictive accuracy for predicting stroke-related functional impairment in stroke patients.

Background A heterogeneous patient population receives endovascular treatment (EVT) for acute ischemic stroke caused by proximal large‐vessel occlusion every day. We aimed to conduct a population‐based study of EVT in the province of Alberta, Canada, to understand the effectiveness in a complete population and how the magnitude of effect differs from the artificial world of clinical trials. Methods and Results Within a 3‐year period (April 2015 to March 2018), 576 patients fit the inclusion criteria of our study and constituted the EVT group of our analysis. The medical treatment group of the ESCAPE (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT [Computed Tomography] to Recanalization Times) trial had 150 patients. Thus, our total sample size was 726. We captured outcomes in clinical routine using administrative data and a linked database method. Primary outcome of our study was home‐time. Home‐time refers to the number of days that the patient was back at premorbid living situation without increase in level of care within 90 days of index stroke event. Median age of patients was 70 years (interquartile range, 59–81 years), and 47.8% were women. Median National Institutes of Health Stroke Scale score was 17 (interquartile range, 13–20). EVT was associated with an increased 90‐day home‐time by an average of 8.5 days compared with medical treatment alone using Cragg hurdle regression (P=0.009). Age and higher National Institutes of Health Stroke Scale score were associated with decreased 90‐day home‐time (both P

The hyperdense sign is a marker of thrombus in non-contrast computed tomography (NCCT) datasets. The aim of this work was to determine optimal Hounsfield unit (HU) thresholds for thrombus segmentation in thin-slice non-contrast CT (NCCT) and use these thresholds to generate 3D thrombus models. Patients with thin-slice baseline NCCT (≤2.5 mm) and MCA-M1 occlusions were included. CTA was registered to NCCT, and three regions of interest (ROIs) were placed in the NCCT, including: the thrombus, contralateral brain tissue, and contralateral patent MCA-M1 artery. Optimal HU thresholds differentiating the thrombus from non-thrombus tissue voxels were calculated using receiver operating characteristic analysis. Linear regression analysis was used to predict the optimal HU threshold for discriminating the clot only based on the average contralateral vessel HU or contralateral parenchyma HU. Three-dimensional models from 70 participants using standard (45 HU) and patient-specific thresholds were generated and compared to CTA clot characteristics. The optimal HU threshold discriminating thrombus in NCCT from other structures varied with a median of 51 (IQR: 49–55). Experts chose 3D models derived using patient-specific HU models as corresponding better to the thrombus seen in CTA in 83.8% (31/37) of cases. Patient-specific HU thresholds for segmenting the thrombus in NCCT can be derived using normal parenchyma. Thrombus segmentation using patient-specific HU thresholds is superior to conventional 45 HU thresholds.

Abstract Background We describe the implementation of minimal sufficient balance randomization, a covariate-adaptive randomization technique, used for the “Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times” (ESCAPE) trial. Methods The ESCAPE trial is a prospective, multicenter, randomized clinical trial that enrolled subjects with the following main inclusion criteria: less than 12 h from symptom onset, age 18 years or older, baseline NIHSS score > 5, ASPECTS score > 5 and computed tomography angiography (CTA) evidence of carotid T/L or M1-segment middle cerebral artery (MCA) occlusion, and at least moderate collaterals by CTA. Patients were randomized using a real-time, dynamic, Internet-based, minimal sufficient balance randomization method that balanced the study arms with respect to baseline covariates including age, sex, baseline NIHSS score, site of arterial occlusion, baseline ASPECTS score and treatment with intravenously administered alteplase. Results Permutation-based tests of group differences confirmed group balance across several baseline covariates including sex (p = 1.00), baseline NIHSS score (p = 0.95), site of arterial occlusion (p = 1.00), baseline ASPECTS score (p = 0.28), treatment with intravenously administered alteplase (p = 0.31), and age (p = 0.67). Conclusion Results from the ESCAPE trial demonstrate the feasibility and the benefit of this covariate adaptive randomization scheme in small-sample trials and for data monitoring endeavors. Trial registration ESCAPE trial – NCT01778335 – at www.clinicaltrials.gov . Registered on 29 January 2013.