Background: Computed tomography (CT) is common imaging modality, though its utilization of iodinated contrast media (ICM) has been historically associated with adverse effects on the kidneys including nephropathy. This study aims to investigate whether administration of ICM in critically ill patients is associated with reduced kidney function and acute kidney injury (AKI). Methods: Data was used from two prospective cohort studies- ACT-TBI and CANCCAP, where patients underwent a whole head CT perfusion with additional CT scans. Serum creatinine (CR) and glomerular filtration rate (eGFR) were sequentially collected for five days of their ICU stay. AKI was evaluated following the KDIGO criteria. Results: Of the 291 patients enrolled, a stratified trend analysis for eGFR could be conducted in 158 patients. No AKI was identified in any of these patients in our study. A significant upward trend in eGFR was observed in those older than 40 years (p=0.027), those with hypertension (p=0.027), diabetes (p=0.027) and history of smoking (p=0.027), The volume of ICM received was not significantly associated with patients’ eGFR. Conclusions: AKI was not identified in critically ill patients who received ICM but significant upward trend of eGFR was seen in older individuals and those with diabetes, hypertension, and a history of smoking.

Background: Informed consent is not always possible in emergency research particularly during life threatening situations. Deferral of consent is an acceptable method in consenting patients; however, it is underutilized. We aim to share our experience with deferred consent. Methods: Participants in two prospective studies underwent a CT-Perfusion scan (intervention) at the time of first hospital imaging, in order not to impact clinical treatment. Deferred consent was then obtained. The primary outcome was the rate of deferred consent. The number of days to obtain consent, refusal rate, and waiver of consent rate was also reported. Results: A total of 291 patients (200 severe traumatic brain injury [TBI] and 91 out-of-hospital cardiac arrest) were enrolled between the two emergency CT-perfusion studies. Some (34/291[11.9%]) could not be reached; waiver of consent was granted by our ethics board. Deferred consent was obtained in 252/291(86.6%). The majority were consented by the partner/spouse (25.2%) and most consents took place within 7-days (76.0%) of enrollment. Five (1.7%) refused consent. Deferred consent rates were higher in the cardiac arrest population (97.8%) compared to the severe TBI population (83.7%). Conclusions: Deferred consent is an acceptable method of obtaining consent in emergency research when the intervention risk is low.

Background: TeleStroke can improve access to stroke care in rural areas. We aim to evaluate the safety and effectiveness of intravenous thrombolysis in our TeleStroke system. Methods: The Manitoba TeleStroke program was rolled out across 7 sites between November 2014 and January 2019. We retrospectively analyzed prospectively collected consecutive acute stroke patients’ data in this duration. The primary outcome was safety and effectiveness measured in terms of 90-day modified Rankin score (mRs). The number of acute ischemic stroke (AIS) patients receiving thrombolysis and endovascular thrombectomy [EVT] and process metrics were also analyzed. R/RStudio version-4.3.2 was used (p<0.05). Results: Of the 1,748 TeleStroke patients (age 71 years [IQR 58-81], female 810[46.3%]), 696 were identified as AIS. Of these, 265(38.1%) received thrombolysis and 48(6.9%) EVT. Ninety-day mortality was 53(20.0%) among those receiving thrombolysis and 117(44.2%) had a favorable outcome (mRs ≤2). Of those who received intravenous thrombolysis, 9 patients (4.2%) were found to have symptomatic intracranial hemorrhage. The median last-seen-normal (LSN)-to-door was121 minutes and the median door-to-needle, 55 minutes. Conclusions: Intravenous thrombolysis was found to be effective with acceptable safety. TeleStroke improved overall access to stroke care and played an important role in identifying AIS patients eligible for thrombolysis and EVT.

Background: Glioblastoma (GB) is the most malignant primary brain tumor. Isolated restricted diffusion (IRD) is restricted diffusion outside the confines of enhancing tumor with no corresponding enhancement on post contrast study. The aim of our study was to prospectively assess the incidence of IRD in GB patients, determine how often these foci proceed to contrast enhancement on follow up, and analyze the survival pattern. Methods: In a prospective pilot cohort study, consecutive adult patients with GB on initial MRI of brain, were included and screened for IRD. All images were independently analyzed by two experienced radiologists. The survival pattern of patients with IRD was assessed with Cox-regression and Kaplan-Meier curve analysis. Results: Of the 52 patients (median age- 63 years; male-63.5%), 21% (11 of 52) exhibited IRD. Inter-rater agreement on the diagnosis of IRD foci was fair (kappa=0.29). Seven (64%) showed enhancement in the IRD focus. The Kaplan Meier analysis revealed a significant decrease (p=0.035) in the survival was observed among patients with IRD focus. Conclusions: IRD focus was seen in 21% of patients with GB, with 64% of these demonstrating enhancement at the IRD focus on follow up imaging. A shorter survival was associated with IRD foci.

Background: Studies have found similar rates of functional independence for men and women after endovascular thrombectomy (EVT). Less is known regarding EVT-related procedural complications and symptomatic intracerebral hemorrhage (sICH) between sexes. Methods: Using the OPTIMISE registry including data from 20 comprehensive stroke centers across Canada between 1/1/2018 and 12/31/2022, we performed a retrospective descriptive analysis of patients divided between men and women. Hemorrhagic transformation on follow-up imaging with associated clinical deterioration was required to define sICH. Results: 3631 patients were included (1778 men and 1853 women) for analysis. Female patients were older (71.8±14.6 vs 68.0±13.1 years, p<0.001). There were no differences in sICH rates (2.5% men vs. 2% women, p= 0.388}. Procedural complication rates were not different between men and women (5.8 vs 5.6% p=0.76): dissection {26 (1.5%) vs. 30 (1.6%), p=0.804}, perforation {11 (0.6%) vs. 7 (0.4%), p=0.426}, embolization {25 (1.4%) vs. 25 (1.3%), p=0.996} and arterial access complications {45 (2.5%) vs. 43 (2.3%), p=0.761}. Conclusions: In this large multicentre registry of stroke patients undergoing EVT, men and women had similarly low and reassuring rates of sICH and procedural complications. This complements previous data showing similar functional outcomes for men and women after EVT.

Background: Telemedicine evaluation for treatment of acute stroke patients with IV thrombolysis has been shown to be beneficial. Its usefulness for the evaluation of patients transferred from a primary stroke centre (PSC) to a comprehensive stroke centre (CSC) for endovascular thrombectomy (EVT) is less well defined. Methods: We retrospectively analyzed the Canadian OPTIMISE registry which included data from 20 comprehensive stroke centers across Canada between January 1, 2018, and December 31, 2022 to compare treatment metrics and early outcomes between two groups: patients evaluated by telemedicine (TM) and patients evaluated in person (non-TM) at the PSC prior to CSC transfer. Results: We included 3317 patients who were transferred from a PSC to a CSC for: 888 TM and 2429 non-TM. There were no major differences in baseline characteristics, including intravenous thrombolysis administration, though the TM group included more men. TM patients had longer onset-to-puncture times (441 vs 403 minutes, p<0.001) and higher symptomatic intracerebral hemorrhage (sICH) rates (7.4% vs 3.7%, p<0.001), but CSC door-to-puncture times and successful recanalization rates did not differ. Conclusions: Patients transferred to a CSC for EVT first evaluated by TM had similar characteristics to those evaluated in person at the PSC, but longer onset-to-puncture times and higher sICH rates.

Background: Anterior (ACS) and posterior circulation (PCS) stroke patients have different clinical presentations and prognoses, though both benefit from endovascular thrombectomy (EVT). We sought to determine whether ACS and PCS patients treated with EVT differed with regards to treatment metrics and functional outcomes. Methods: We retrospectively analysed theCanadian OPTIMISE registry which included data from 20 comprehensive stroke centers across Canada between January 1, 2018, and December 31, 2022. We performed a descriptive analysis of patients divided in two groups (ACS= carotid artery and its branches, PCS= vertebrobasilar system). Results: Of the 6391 patients included (5929 ACS and 462 PCS), PSC patients were younger (67 vs. 71.3, p<0.001), more often male (61.9% vs. 48.6%, p<0.001), had longer (in minutes) onset-to-door (362 vs. 256, p<0.001), door-to-needle (172 vs. 144, p=0.0016), and onset-to-puncture (459 vs. 329, p<0.001) times. They were less often thrombolyzed (39.8% vs. 50.4%, p<0.001), and more frequently underwent general anesthesia (47.6% vs. 10.6%, p<0.001). Successful reperfusion and functional independence at 90 days were similar between the two groups. Conclusions: Patients with PCS had worst treatment metrics than ACS. Strategies to improve PCS management times are critical to decrease these disparities, including faster pre-hospital recognition and in-hospital workflows.

Polar ring galaxies (PRGs) are a unique class of galaxies characterised by a ring of gas and stars orbiting nearly orthogonal to the main body. This study delves into the evolutionary trajectory of PRGs using the exemplary trio of NGC 3718, NGC 2685, and NGC 4262. We investigate the distinct features of PRGs by analysing their ring and host components to reveal their unique characteristics through spectral energy distribution (SED) fitting. Using CIGALE, we performed SED fitting to independently analyse the ring and host spatially resolved regions, marking the first decomposed SED analysis for PRGs, which examines stellar populations using high-resolution observations from AstroSat UVIT at a resolved scale. The UV-optical surface profiles provide an initial idea that distinct patterns in the galaxies, with differences in FUV and NUV, suggest three distinct stages of ring evolution in the selected galaxies. The study of resolved-scale stellar regions reveals that the ring regions are generally younger than their host galaxies, with the age disparity progressively decreasing along the evolutionary sequence from NGC 3718 to NGC 4262. Star formation rates (SFR) also exhibit a consistent pattern, with higher SFR in the ring of NGC 3718 compared to the others, and a progressive decrease through NGC 2685 and NGC 4262. Finally, the representation of the galaxies in the HI gas fraction versus the NUV–$\text r$ plane supports the idea that they are in three different evolutionary stages of PRG evolution, with NGC 3718 in the initial stage, NGC 2685 in the intermediate stage, and NGC 4262 representing the final stage. This study concludes that PRGs undergo various evolutionary stages, as evidenced by the observed features in the ring and host components. NGC 3718, NGC 2685, and NGC 4262 represent different stages of this evolution, highlighting the dynamic nature of PRGs and emphasising the importance of studying their evolutionary processes to gain insights into galactic formation and evolution.

This editorial considers the value and nature of academic psychiatry by asking what defines the specialty and psychiatrists as academics. We frame academic psychiatry as a way of thinking that benefits clinical services and discuss how to inspire the next generation of academics.

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: 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: 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.

OBJECTIVES/GOALS: In vitro models that mimic the human respiratory system are needed to assess the toxicity of inhaled contaminants. Therefore, our goal is to establish a Dosimetric Aerosol in-Vitro Inhalation Device (DAVID) that delivers aerosols in different patterns to human lung cells cultured at an air-liquid interface (ALI). METHODS/STUDY POPULATION: The collection unit of DAVID was modified in this study to accommodate different deposition patterns (spots, annular ring, rectangle & circle). CuO aerosols of varying concentrations were generated using a 6-jet Collison nebulizer for varying time periods to achieve different doses. To quantify the doses that were delivered to cells, the samples were digested with nitric acid & analyzed by Inductively Coupled Plasma-Optical Emission Spectrometry. Following the exposure of A549 cells to CuO aerosols, cytotoxicity and mRNA expression (i.e., HMOX1 & IL-8) will be assessed via LDH and RT-qPCR to determine the effect of regional (mass deposited/area of the pattern) and global (mass deposited/area of the cell culture insert) doses in cells. RESULTS/ANTICIPATED RESULTS: The deposition areas covered by rectangular, spot, annular ring, and circular patterns are estimated to be 6, 17, 27 and 85% of the insert’s surface area, onto which cells are cultured. Results for the patterns tested (spots and annular ring) show that both the regional and global doses were greater for spots than annular ring. Also, the regional doses were higher than global doses. Irrespective of the patterns, the global doses were the same for nebulizer suspensions of 0.1-1 mg/mL. Statistical analysis by ANOVA revealed there was no significant difference in doses between replicate inserts used in the same trial. We anticipate that regional doses with aerosol deposition to a larger surface area of the cell culture insert will correspond with higher cytotoxicity and mRNA expression of HMOX1 and IL-8 in cells. DISCUSSION/SIGNIFICANCE: There are limited in vitro exposure systems that can efficiently deliver aerosols to lung cells, while also mimicking inhalation by humans. In addition to addressing this knowledge gap, we will show the role of regional & global doses in studying cellular response & the ability of DAVID to deliver aerosols in different deposition patterns.

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.

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.