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Semantic segmentation is a critical part of observation-driven research in glaciology. Using remote sensing to quantify how features change (e.g. glacier termini, supraglacial lakes, icebergs, crevasses) is particularly important in polar regions, where glaciological features may be spatially small but reflect important shifts in boundary conditions. In this study, we assess the utility of the Segment Anything Model (SAM), released by Meta AI Research, for cryosphere research. SAM is a foundational AI model that generates segmentation masks without additional training data. This is highly beneficial in polar science because pre-existing training data rarely exist. Widely-used conventional deep learning models such as UNet require tens of thousands of training labels to perform effectively. We show that the Segment Anything Model performs well for different features (icebergs, glacier termini, supra-glacial lakes, crevasses), in different environmental settings (open water, mélange, and sea ice), with different sensors (Sentinel-1, Sentinel-2, Planet, timelapse photographs) and different spatial resolutions. Due to the performance, versatility, and cross-platform adaptability of SAM, we conclude that it is a powerful and robust model for cryosphere research.
Background: Orbital infarction syndrome (OIS) is a rare entity defined as acute ischemia of intraorbital structures. Three case reports of OIS post-endovascular thrombectomy (EVT) have recently been published, two demonstrating absent choroid blush (CB) on digital subtraction angiogram (DSA). Our goals are to determine the true incidence of OIS post-EVT and to identify imaging findings (e.g. CB) that may alert neurologists to potential cases. Methods: A retrospective cohort study including all EVT patients from Health Sciences Center (HSC), Winnipeg in 2019-20 was performed. Patient charts were reviewed to determine the incidence of OIS. Pre- and post-EVT DSA images were reviewed, and the sensitivity and specificity of absent CB for OIS was calculated. Results: Out of 248 patients, 13 were excluded for incomplete charts, and 4 cases (1.7%) of OIS were discovered. During sensitivity/specificity analysis of absent CB for OIS, 51 patients were excluded for inadequate imaging. There were 4 true positives, 0 false-negatives, 113 true-negatives, and 67 false-positives; resulting in a sensitivity of 100% and worst-case scenario specificity of 63% (assuming all 51 indeterminate cases were false positives). Conclusions: OIS is rare post-EVT with an incidence of 1.7%. Absent CB is very sensitive for diagnosing OIS with lower specificity.
Background: Women are reported to have worse outcomes than men following ischemic stroke despite similar treatment effects for thrombolysis and endovascular treatment. Methods: We performed a post-hoc analysis of patients with acute ischemic stroke and intracranial occlusion enrolled in INTERRSeCT, an international prospective cohort study. We compared workflow times, reperfusion therapy choices, and 90-day modified Rankin scale (mRS) scores. Results: We included 575 patients, mean age 70.2 years (SD: 13.1) and 48.5% female. There were no significant sex differences in onset-to-CT (males: 115 minutes [IQR: 72-171], females: 114 minutes [IQR: 75-196] ) or CT-to-thrombolysis time (males: 24 minutes [IQR: 17-32], females: 23 minutes [IQR: 18-36]). However, female participants had a 12-minute faster CT-to-groin-puncture time, p=0.001. Reperfusion therapies did not significantly differ by sex. Reperfusion therapies included thrombolysis alone (males: 46%, females: 49%), EVT alone (males: 34%, females: 34%), thrombolysis plus EVT (males: 8%, females 9%) and conservative management (males: 12%, females: 8%). Median 90-day mRS was 2 (IQR: 1-4) in both males and females, p=0.1. Conclusions: In the INTERRSeCT cohort, rates of reperfusion therapy, workflow times and 90-day outcomes were similar between sexes, suggesting that women are not subject to any poorer performance in key quality indicators for reperfusion treatment for acute stroke.
Background: Radiologic imaging has become integral in not only the detection and diagnosis of subdural hematoma, but also in guiding potential treatment options. Particularly, in the arena of chronic subdural hematoma, which has conventionally been managed via surgical drainage, although is shifting toward procedural intervention with embolization of the middle meningeal artery. This paper aims to review the imaging manifestations of subdural hematoma as a function of chronicity, standardized methods of measurement, and identifying the middle meningeal artery and its clinically significant variant anatomy as it pertains to embolization planning. Methods: A literature search using key terms and titles was conducted for articles containing imaging characteristics of subdural hematoma, approaches to measurement, and middle meningeal artery anatomy as the primary focus. Results: The expected evolution of subdural hematoma over time encompasses a broad array of imaging characteristics. Attempts at standardizing hematoma measurements include width, volume, and midline shift. Given the implication of the middle meningeal artery in potential therapeutic embolization, familiarity with its anatomy is vital not only for mapping access, but also for delineating possible dangerous collaterals. Conclusions: Equipped with a more comprehensive approach to characterizing subdural hematoma, the radiologist will be able to curate findings of greater utility to the clinician.
Background: The burden and outcome of stroke in indigenous populations is less well understood. This review evaluates ischemic stroke outcomes in indigenous populations as compared to the general population in the context of recent advances in ischemic stroke therapy. Methods: The OVID Medline and EMBASE databases were searched for this review. Clinical outcome was measured using standardized outcome scale (eg. mRS) at 90 days following stroke intervention in indigenous as compared to non-indigenous adult populations. Results: 897 studies were identified, with 4 studies included in the final analysis. A total of (n=68895) patients were included who underwent thrombolysis. Study populations from Australia, New Zealand, United States and Canada comprised of (n=2012) indigenous patients. Mortality was significantly higher in indigenous populations as compared to non-indigenous (Odds Ratio-1.28, 95% CI-1.12; 1.46). The odds ratios of atrial fibrillation (1.26, 95% CI-1.12;– 1.41), diabetes (1.43, 95% CI- 1.27; 1.62), hypertension (1.33, 95% CI- 1.17; 1.51) and IHD (0.71, 95% CI- 0.62; 0.81) in indigenous patients was significantly higher than in non-indigenous patients. Conclusions: Indigenous populations undergoing stroke therapy are at a significantly increased risk of mortality as compared to non-indigenous populations. Comorbidities including diabetes, atrial fibrillation and hypertension are more prevalent in indigenous populations.
Background: Thrombolysis (tPA) and endovascular thrombectomy (EVT) are interventions for acute ischemic stroke (AIS) that can be accompanied by intracerebral hemorrhage (ICH), which can alter the patient’s management, or contrast extravasation (CE), which is relatively benign. Previous retrospective studies have shown that dual-energy CT (DECT) is significantly more accurate for differentiating ICH from CE compared to conventional, single-energy CT (SECT). We are performing a prospective study to investigate this question. Methods: Our primary outcome is the sensitivity and specificity of DECT in differentiating ICH from CE. In AIS patients who receive intervention, we will be performing a DECT scan at the same time as the standard-of-care SECT scan at 24 hours post-intervention. In patients who have a hyperdensity on CT, a repeat scan will be done at 72-hours, which will be used as the gold-standard to determine if the hyperdensity was ICH or CE. Results: We expect that DECT will be significantly more sensitive and specific for differentiating ICH from CE compared to SECT. Conclusions: This study will determine if DECT is superior to SECT in differentiating ICH from CE, validate the use of DECT in AIS patients who receive intervention, and potentially change the imaging paradigm for acute stroke in the future.
Background: Sex differences in treatment response to intravenous thrombolysis (IVT) are poorly characterized. We compared sex-disaggregated outcomes in patients receiving IVT for acute ischemic stroke in the Alteplase compared to Tenecteplase (AcT) trial, a Canadian multicentre, randomised trial. Methods: In this post-hoc analysis, the primary outcome was excellent functional outcome (modified Rankin Score [mRS] 0-1) at 90 days. Secondary and safety outcomes included return to baseline function, successful reperfusion (eTICI≥2b), death and symptomatic intracerebral hemorrhage. Results: Of 1577 patients, there were 755 women and 822 men (median age 77 [68-86]; 70 [59-79]). There were no differences in rates of mRS 0-1 (aRR 0.95 [0.86-1.06]), return to baseline function (aRR 0.94 [0.84-1.06]), reperfusion (aRR 0.98 [0.80-1.19]) and death (aRR 0.91 [0.79-1.18]). There was no effect modification by treatment type on the association between sex and outcomes. The probability of excellent functional outcome decreased with increasing onset-to-needle time. This relation did not vary by sex (pinteraction 0.42). Conclusions: The AcT trial demonstrated comparable functional, safety and angiographic outcomes by sex. This effect did not differ between alteplase and tenecteplase. The pragmatic enrolment and broad national participation in AcT provide reassurance that there do not appear to be sex differences in outcomes amongst Canadians receiving IVT.
Antiseizure medications (ASMs) are the second most widely prescribed psychotropic for people with intellectual disabilities in England. Multiple psychotropic prescribing is prevalent in almost half of people with intellectual disabilities on ASMs. This analysis identifies limited evidence of ASM benefit in challenging behaviour management and suggests improvements needed to inform clinical practice.
Background: The purpose of this systematic review was to synthesize evidence based on existing studies on the ability of initial imaging to predict mortality in severe traumatic brain injuries (TBIs) in pediatric patients. Methods: An experienced librarian searched for all existing studies based on the inclusion and exclusion criteria. The studies were screened by two blinded reviewers. The data was extracted to calculate the sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predicted value (NPV), area under the curve (AUC), and receiver operating characteristic (ROC) for extradural hematoma (EDH), subdural hematoma (SDH), traumatic subarachnoid hemorrhage (tSAH), skull fractures, and edema. Results: Of the 3277 studies included in the search, data could only be extracted from 22 studies. There were a total of 2219 patients, 747 females, and 1461 males. 564 patients died and 1651 survived. 293 patients had SDH, 76 had EDH, 347 had tSAH, 244 had skull fractures, and 416 had edema. Seven of the studies had sufficient data to calculate the AUC, ROC, and generate a forest plot for the imaging findings. Conclusions: Out of the different CT scan findings, brain edema had the highest SN, PPV, NPV, and AUC. EDH had the highest SP to predict in hospital mortality.
Background: Chronic subdural hematoma (CSDH) is of the most encountered neurosurgical cases, predominantly in older individuals. Surgical drainage remains the mainstay, yet is challenged by variable recurrence rates. Less invasive methods of embolization of the middle meningeal artery (EMMA) could reduce the recurrence rates. Before adopting a newer treatment (EMMA), it is prudent to establish the outcomes from surgical drainage. The purpose of this study is to assess the clinical outcome and recurrence risk in surgically treated CSDH patients. Methods: A retrospective search of our surgical database was done to identify CSDH patients undergoing surgical drainage in 2019-2020. Demographic and clinical details were collected through chart review and a qualitative statistical analysis was performed. Results: A total of 136 patients (mean age-68 years; range-21-100 years; Male-105) with CSDH underwent surgical drainage with repeat surgery in 11.8%(n=16). Periprocedural mortality and morbidity were 8.8%(n=12) and 20.6%(n=28), respectively. No radiological follow-up was seen in 30(22%) of patients. Of those with follow-up, recurrence was seen in 21.7%(n=23). Mean hospital stay was 9.64 days. Conclusions: Our retrospective study showed periprocedural morbidity (20.6%) and mortality (8.8%) with a 21.7% risk of recurrence. This is likely due to older patients but is in keeping with what is reported in the literature.
Background: Embolization of middle meningeal artery (EMMA) is an emerging treatment for CSDH and a method to decrease CSDH recurrence. We report a single Canadian center experience of EMMA for the management of CSDH. Methods: Consecutive EMMA patients during the period July 2020 to September 2021 were retrospectively included in this series. EMMA procedures were performed using polyvinyl alcohol particles or liquid embolic agent. All patients were followed clinically and radiographically as per standard of care. Results: A total of 20 patients CSDH (mean 65.6 years; range 14-85 yrs; male 16) underwent 20 EMMA procedures. CSDH occured on the left in 13 patients, right in 4 patients and bilateral in 3 patients. No patients had periprocedural complications. There was no recurrence of CSDH on the EMMA treated side. The mean SDH size decreased from 18.4 +/- 6.34 mm at the time of presentation to 5.31 +/ 3.84 mm at last follow up. The proportion of patients with an mRS of 2 or less increased from 65% to 76%. Conclusions: EMMA was found to be effective and safe in the management of CSDH with no evidence of recurrence on the treated side. Left sided hematomas appear to be more common that right sided hematomas.
Background: The coronavirus disease 2019 (COVID-19) pandemic has led the implementation of institutional infection control protocols. This study will determine the effects of these protocols on outcomes of acute ischemic stroke (AIS) patients treated with endovascular therapy (EVT). Methods: Uninterrupted time series analysis of the impact of COVID-19 safety protocols on AIS patients undergoing EVT. We analyze data from prospectively collected quality improvement databases at 6 centers from March 11, 2019 to March 10, 2021. The primary outcome is 90-day modified Rankin Score (mRS). The secondary outcomes are angiographic time metrics. Results: Preliminary analysis of one stroke center included 214 EVT patients (n=150 pre-pandemic). Baseline characteristics were comparable between the two periods. Time metrics “last seen normal to puncture” (305.7 vs 407.2 min; p=0.05) and “hospital arrival to puncture” (80.4 vs 121.2 min; p=0.04) were significantly longer during pandemic compared to pre-pandemic. We found no significant difference in 90-day mRS (2.0 vs 2.2; p=0.506) or successful EVT rate (89.6% vs 90%; p=0.93). Conclusions: Our results indicate an increase in key time metrics of EVT in AIS during pandemic, likely related to infection control measures. Despite the delays, we found no difference in clinical outcomes between the two periods.
Between 21 November and 22 December 2020, a SARS-CoV-2 community testing pilot took place in the South Wales Valleys. We conducted a case-control study in adults taking part in the pilot using an anonymous online questionnaire. Social, demographic and behavioural factors were compared in people with a positive lateral flow test (cases) and a sample of negatives (controls). A total of 199 cases and 2621 controls completed a questionnaire (response rates: 27.1 and 37.6% respectively). Following adjustment, cases were more likely to work in the hospitality sector (aOR 3.39, 95% CI 1.43–8.03), social care (aOR 2.63, 1.22–5.67) or healthcare (aOR 2.31, 1.29–4.13), live with someone self-isolating due to contact with a case (aOR 3.07, 2.03–4.62), visit a pub (aOR 2.87, 1.11–7.37) and smoke or vape (aOR 1.54, 1.02–2.32). In this community, and at this point in the epidemic, reducing transmission from a household contact who is self-isolating would have the biggest public health impact (population-attributable fraction: 0.2). As restrictions on social mixing are relaxed, hospitality venues will become of greater public health importance, and those working in this sector should be adequately protected. Smoking or vaping may be an important modifiable risk factor.
Background: Lumbar disc herniation (LDH) is a risk factor for Modic change (MC) development on spinal MRI. MC has been associated with worse pre- and post-operative pain, disability, and health-related quality of life (HRQoL). We examined the relationship between pre-operative MC and post-operative assessment scores for patients receiving discectomy (LD) or transforaminal interbody fusion (TLIF) for LDH. Methods: We reviewed 285 primary single-level surgeries. Pre-operative and 12-month post-operative assessment scores: Visual Analog Scale Leg-Pain (VAS-LP), Oswestry Disability Index (ODI), and Short-Form-36 Physical Component Summary (SF-36-PCS). MC subgroup on pre-operative MRI was recorded by a single neuroradiologist. Results: 179 patients were included. The sample prevalence of MC on pre-operative MRI was 62%; MC2 was most common (35%). No differences in pre-operative scores were identified, regardless of present or absent MC. For the overall cohort, improvement in assessment scores were observed: SF-36 improved an average of 8.2 points (95% CI: [5.8, 10.7]), ODI by 11.3 points (95% CI: [8.7, 14.0]), and VAS by 2.8 points (95% CI: [2.1, 3.5]). In nearly all cases, MCID values were met. Conclusions: Clinically significant improvement in post-operative pain, disability, and HRQoL was observed for both procedures. Modic change on pre-operative MRI was not associated with worse clinical assessment scores.
Background: Vascular closure devices (VCDs) are routinely used in both neurovascular and vascular interventional procedures. The purpose of our study was to assess the safety and efficacy of the VCDs for diagnostic and therapeutic neurovascular and vascular procedures. Methods: The study was approved by the University of Manitoba research ethics board. A retrospective review was conducted of the database between January 2017 and December 2019. The data was collected from the Picture Archiving and Communication System (PACS) and collected in an excel spreadsheet. Patient demographics and clinical information was collected. Descriptive statistics and chi-squared tests were performed using STATA 13 software. A p<0.05 was considered significant. Results: VCD was used in a total of 2072 patients. VCDs were successfully deployed in 94% with 6% failure. Immediate perioperative complications were seen in 6.2% patients. The complication rates were significantly (p=0.025) associated with the type of procedure. Complications were seen significantly (p=0.044) higher in outpatients compared to inpatients and those from emergency room. Conclusions: VCDs were successfully deployed in 96VCDs were successfully deployed in 94% of the patient with 6% perioperative complications. Most of the complications were minor and complications were more commonly associated with outpatients procedures and with diagnostic vascular procedures.
Background: The coronavirus disease 2019 (COVID-19) pandemic has led an implementation of institutional infection control protocols. This study will determine the effects of these protocols on outcomes of acute ischemic stroke (AIS) patients treated with endovascular therapy (EVT). Methods: Uninterrupted time series analysis of the impact of COVID-19 safety protocols on AIS patients undergoing EVT. We analyze data from prospectively collected quality improvement databases at 9 centers from March 11, 2019 to March 10, 2021. The primary outcome is 90-day modified Rankin Score (mRS). The secondary outcomes are angiographic time metrics. Results: Preliminary analysis of one stroke center included 214 EVT patients (n=144 pre-pandemic). Baseline characteristics were comparable between the two periods. Time metrics “last seen normal to puncture” (305.7 vs 407.2 min; p=0.05) and “hospital arrival to puncture” (80.4 vs 121.2 min; p=0.04) were significantly longer during pandemic compared to pre-pandemic. We found no significant difference in 90-day mRS (2.0 vs 2.2; p=0.506) or successful EVT rate (89.6% vs 90%; p=0.93). Conclusions: Our results indicate an increase in key time metrics of EVT in AIS during the pandemic, likely related to infection control measures. Despite the delays, we found no difference in clinical outcomes between the two periods.
Electronic discovery (e-discovery) is an integral component of legal informatics, touching on everything from search and artificial intelligence to design and legal services transformation. Any discussion of electronic discovery must begin with an explanation of its relevance to legal work. E-discovery – also known as “ediscovery” or, somewhat datedly, “eDiscovery” – is the discovery in legal proceedings of evidence in an electronic format. Due to the nature of modern technology, e-discovery encompasses an overwhelming majority of evidence, such that e-discovery and other forms of discovery have become virtually synonymous. As such, legal discovery is now fraught with issues concerning how information is stored, retrieved, exchanged, and generally made accessible to parties during legal proceedings. A common challenge for attorneys is what to do with a multi-terabyte collection of evidence that consists of millions of documents across hundreds of file types, with only a matter of months before their first depositions. The best solutions to this kind of increasingly common challenge will include recourse to big data and machine learning, which are discussed in this chapter.
Clinician-patient communication is a major factor in influencing outcomes of healthcare. Complexity increases if an individual has multiple health needs requiring support of different clinicians or agencies.
To develop and evidence a simple dynamic computerised tool to capture and communicate outcomes of intervention or alteration in clinical need in patients with multiple chronic health needs.
A MS Excel algorithm was designed for swift capture of clinical information discussed in an appointment using pre-designed set of evidenced based domains. An instant personalized single screen visual is produced to facilitate information sharing and decision-making. The display is responsive to compare changes across time. A prototype was conceptually tested in an epilepsy clinic for people with Intellectual disability (ID) due to the unique challenges posed in this population.
Evidence across 300 patients with ID and epilepsy showed the tool works by enhancing reflective communication, compliance and therapeutic relationship. Medication and appointment compliance was 95% and patient satisfaction over 90%.
To discuss all influencing health factors in a consultation is a communication challenge esp. if the patient has multiple health needs. A picture equals 1000 words and helps address the cognitive complexity of verbal information. The radar offers an evidenced based common framework to host care plans of different health conditions. It provides individualised easy view person centred care plans to allow patients to gain insight on how the different conditions impact on their overall well being and be active participants. The tool will be practically demonstrated.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Although the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke caused by intracranial anterior circulation large vessel occlusion (LVO) is proven, demonstration of local effectiveness is critical for health system planning and resource allocation because of the complexity and cost of this treatment.
Using our prospective registry, we identified all patients who underwent EVT for out-of-hospital LVO stroke from February 1, 2013 through January 31, 2017 (n = 44), and matched them 1:1 in a hierarchical fashion with control patients not treated with EVT based on age (±5 years), prehospital functional status, stroke syndrome, severity, and thrombolysis administration. Demographics, in-hospital mortality, discharge disposition from acute care, length of hospitalization, and functional status at discharge from acute care and at follow-up were compared between cases and controls.
For EVT-treated patients (median age 66, 50% women), the median onset-to-recanalization interval was 247 min, and successful recanalization was achieved in 30/44 (91%). Alteplase was administered in 75% of cases and 57% of controls (p = 0.07). In-hospital mortality was 11% among the cases and 36% in the control group (p = 0.006); this survival benefit persisted during follow-up (p = 0.014). More EVT patients were discharged home from acute care (50% vs. 18%, p = 0.002). Among survivors, there were nonsignificant trends in favor of EVT for median length of hospitalization (14 vs. 41 days, p = 0.11) and functional independence at follow-up (51% vs. 32%, p = 0.079).
EVT improved survival and decreased disability. This demonstration of single-center effectiveness may help facilitate expansion of EVT services in similar health-care jurisdictions.
Endovascular thrombectomy (EVT) is efficacious for ischemic stroke caused by proximal intracranial large-vessel occlusion involving the anterior cerebral circulation. However, evidence of its cost-effectiveness, especially in a real-world setting, is limited. We assessed whether EVT ± tissue plasminogen activator (tPA) was cost-effective when compared with standard care ± tPA at our center.
We identified patients treated with EVT ± tPA after the Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing computed tomography to recanalization times trial from our prospective stroke registry from February 1, 2013 to January 31, 2017. Patients admitted before February 2013 and treated with standard care ± tPA constitute the controls. The sample size was 88. Cost-effectiveness was assessed using the net monetary benefit (NMB). Differences in average costs and quality-adjusted life years (QALYs) were estimated using the augmented inverse probability weighted estimator. We accounted for sampling and methodological uncertainty in sensitivity analyses.
Patients treated with EVT ± tPA had a net gain of 2.89 [95% confidence interval (CI): 0.93–4.99] QALYs at an additional cost of $22,200 (95% CI: −28,902–78,244) per patient compared with the standard care ± tPA group. The NMB was $122,300 (95% CI: −4777–253,133) with a 0.85 probability of being cost-effective. The expected savings to the healthcare system would amount to $321,334 per year.
EVT ± tPA had higher costs and higher QALYs compared with the control, and is likely to be cost-effective at a willingness-to-pay threshold of $50,000 per QALY.