Context reinstatement requires a schema relevant virtual environment to benefit object recall.

How does our environment impact what we will later remember? Early work in real-world environments suggested that having matching encoding/retrieval contexts improves memory. However, some laboratory-based studies have not replicated this advantageous context-dependent memory effect. Using virtual reality methods, we find support for context-dependent memory effects and examine an influence of memory schema and dynamic environments. Participants (N = 240) remembered more objects when in the same virtual environment (context) as during encoding. This traded-off with falsely "recognizing" more similar lures. Experimentally manipulating the virtual objects and environments revealed that a congruent object/environment schema aids recall (but not recognition), though a dynamic background does not. These findings further our understanding of when and how context affects our memory through a naturalistic approach to studying such effects.

Advancing early detection of suicide? A national study examining socio-demographic factors, antecedent stressors and long-term history of self-harm.

BACKGROUND: A range of factors including mental disorders, adverse events and history of self-harm are associated with suicide risk. Further examination is needed of the characteristics of suicides which occur without established risk factors, using national surveillance systems. METHODS: Data on all suicides in Ireland from 2015 to 2017 were drawn from the Irish Probable Suicide Deaths Study (IPSDS). Variables examined included socio-demographics, psychiatric history and precipitant stressors. Suicide data were linked with data on prior self-harm from the National Self-Harm Registry Ireland (NSHRI). Latent Class Analysis (LCA) was used to identify sub-groups of suicide cases. RESULTS: Of the 1809 individuals who died by suicide, 401 (22.2 %) had a history of hospital-treated self-harm. Four distinct profiles of suicides were identified. One group was marked by high levels of prior self-harm and mental health conditions. Two of the groups included few individuals with a history of self-harm but had notably high levels of mental health conditions. These two groups had relatively high levels of reported chronic pain or illness but differed in terms of socio-demographics. The final group, predominantly male, had markedly low levels of mental health conditions or self-harm but high levels of personal stressors and substance use. LIMITATIONS: The use of coronial data may be limited by bias in the collecting of information from the deceased's family members. CONCLUSIONS: A sub-group of suicide cases exists without any psychiatric or self-harm history but with salient occupational or health-related proximal stressors. Suicide prevention interventions should include occupational settings and should promote mental health literacy.

Evaluation of a national clinical programme for the management of self-harm in hospital emergency departments: impact on patient outcomes and the provision of care.

BACKGROUND: Emergency departments are important points of intervention, to reduce the risk of further self-harm and suicide. A national programme to standardise the management of people presenting to the emergency department with self-harm and suicidal ideation (NCPSHI) was introduced in Ireland in 2014. The aim of this study was to evaluate the impact of the NCPSHI on patient outcomes and provision of care. METHODS: Data on self-harm presentations were obtained from the National Self-Harm Registry Ireland from 2012 to 2017. The impacts of the NCPSHI on study outcomes (3-month self-harm repetition, biopsychosocial assessment provision, admission, post-discharge referral, and self-discharge) were examined at an individual and aggregate (hospital) level, using a before and after study design and interrupted time series analyses, respectively. The 15 hospitals that implemented the programme by January 2015 (of a total of 24 between 2015 and 2017) were included in the analyses. RESULTS: There were 31,970 self-harm presentations during the study period. In hospitals with no service for self-harm (n = 4), risk of patients not being assessed reduced from 31.8 to 24.7% following the introduction of the NCPSHI. Mental health referral in this hospital group increased from 42.2 to 59.0% and medical admission decreased from 27.5 to 24.3%. Signs of a reduction in self-harm repetition were observed for this hospital group, from 35.1 to 30.4% among individuals with a history of self-harm, but statistical evidence was weak. In hospitals with a pre-existing liaison psychiatry service (n = 7), risk of self-discharge was lower post-NCPSHI (17.8% vs. 14.8%). In hospitals with liaison nurse(s) pre-NCPSHI (n = 4), medical admission reduced (27.5% vs. 24.3%) and there was an increase in self-harm repetition (from 5.2 to 7.8%. for those without a self-harm history). CONCLUSION: The NCPSHI was associated with improvements in the provision of care across hospital groups, particularly those with no prior service for self-harm, highlighting the need to consider pre-existing context in implementation planning. Our evaluation emphasises the need for proper resourcing to support the implementation of clinical guidelines on the provision of care for people presenting to hospital with self-harm.

Gate-controlled suppression of light-driven proton transport through graphene electrodes.

Recent experiments demonstrated that proton transport through graphene electrodes can be accelerated by over an order of magnitude with low intensity illumination. Here we show that this photo-effect can be suppressed for a tuneable fraction of the infra-red spectrum by applying a voltage bias. Using photocurrent measurements and Raman spectroscopy, we show that such fraction can be selected by tuning the Fermi energy of electrons in graphene with a bias, a phenomenon controlled by Pauli blocking of photo-excited electrons. These findings demonstrate a dependence between graphene's electronic and proton transport properties and provide fundamental insights into molecularly thin electrode-electrolyte interfaces and their interaction with light.

Proton transport through nanoscale corrugations in two-dimensional crystals.

Defect-free graphene is impermeable to all atoms1-5 and ions6,7 under ambient conditions. Experiments that can resolve gas flows of a few atoms per hour through micrometre-sized membranes found that monocrystalline graphene is completely impermeable to helium, the smallest atom2,5. Such membranes were also shown to be impermeable to all ions, including the smallest one, lithium6,7. By contrast, graphene was reported to be highly permeable to protons, nuclei of hydrogen atoms8,9. There is no consensus, however, either on the mechanism behind the unexpectedly high proton permeability10-14 or even on whether it requires defects in graphene's crystal lattice6,8,15-17. Here, using high-resolution scanning electrochemical cell microscopy, we show that, although proton permeation through mechanically exfoliated monolayers of graphene and hexagonal boron nitride cannot be attributed to any structural defects, nanoscale non-flatness of two-dimensional membranes greatly facilitates proton transport. The spatial distribution of proton currents visualized by scanning electrochemical cell microscopy reveals marked inhomogeneities that are strongly correlated with nanoscale wrinkles and other features where strain is accumulated. Our results highlight nanoscale morphology as an important parameter enabling proton transport through two-dimensional crystals, mostly considered and modelled as flat, and indicate that strain and curvature can be used as additional degrees of freedom to control the proton permeability of two-dimensional materials.

Representations within the Intraparietal Sulcus Distinguish Numerical Tasks and Formats.

How does our brain understand the number five when it is written as an Arabic numeral, and when presented as five fingers held up? Four facets have been implicated in adult numerical processing: semantic, visual, manual, and phonological/verbal. Here, we ask how the brain represents each, using a combination of tasks and stimuli. We collected fMRI data from adult participants while they completed our novel "four number code" paradigm. In this paradigm, participants viewed one of two stimulus types to tap into the visual and manual number codes, respectively. Concurrently, they completed one of two tasks to tap into the semantic and phonological/verbal number codes, respectively. Classification analyses revealed that neural codes representing distinctions between the number comparison and phonological tasks were generalizable across format (e.g., Arabic numerals to hands) within intraparietal sulcus (IPS), angular gyrus, and precentral gyrus. Neural codes representing distinctions between formats were generalizable across tasks within visual areas such as fusiform gyrus and calcarine sulcus, as well as within IPS. Our results identify the neural facets of numerical processing within a single paradigm and suggest that IPS is sensitive to distinctions between semantic and phonological/verbal, as well as visual and manual, facets of number representations.

Concepts and recent advances in microchip electrophoresis coupled to mass spectrometry: Technologies and applications.

The online coupling of microchip electrophoresis (ME) as a fast, highly efficient, and low-cost miniaturized separation technique to mass spectrometry (MS) as an information-rich and sensitive characterization technique results in ME-MS an attractive tool for various applications. In this paper, we review the basic concepts and latest advances in technology for ME coupled to MS during the period of 2016-2021, covering microchip materials, structures, fabrication techniques, and interfacing to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization-MS. Two critical issues in coupling ME and ESI-MS include the electrical connection used to define the electrophoretic field strength along the separation channel and the generation of the electrospray for MS detection, as well as, a miniaturized ESI-tip. The recent commercialization of ME-MS in zone electrophoresis and isoelectric focusing modes has led to the widespread application of these techniques in academia and industry. Here we summarize recent applications of ME-MS for the separation and detection of antibodies, proteins, peptides, carbohydrates, metabolites, and so on. Throughout the paper these applications are discussed in the context of benefits and limitations of ME-MS in comparison to alternative techniques.

Improved Locomotor Recovery in a Rat Model of Spinal Cord Injury by BioLuminescent-OptoGenetic (BL-OG) Stimulation with an Enhanced Luminopsin.

Irrespective of the many strategies focused on dealing with spinal cord injury (SCI), there is still no way to restore motor function efficiently or an adequate regenerative therapy. One promising method that could potentially prove highly beneficial for rehabilitation in patients is to re-engage specific neuronal populations of the spinal cord following SCI. Targeted activation may maintain and strengthen existing neuronal connections and/or facilitate the reorganization and development of new connections. BioLuminescent-OptoGenetics (BL-OG) presents an avenue to non-invasively and specifically stimulate neurons; genetically targeted neurons express luminopsins (LMOs), light-emitting luciferases tethered to light-sensitive channelrhodopsins that are activated by adding the luciferase substrate coelenterazine (CTZ). This approach employs ion channels for current conduction while activating the channels through treatment with the small molecule CTZ, thus allowing non-invasive stimulation of all targeted neurons. We previously showed the efficacy of this approach for improving locomotor recovery following severe spinal cord contusion injury in rats expressing the excitatory luminopsin 3 (LMO3) under control of a pan-neuronal and motor-neuron-specific promoter with CTZ applied through a lateral ventricle cannula. The goal of the present study was to test a new generation of LMOs based on opsins with higher light sensitivity which will allow for peripheral delivery of the CTZ. In this construct, the slow-burn Gaussia luciferase variant (sbGLuc) is fused to the opsin CheRiff, creating LMO3.2. Taking advantage of the high light sensitivity of this opsin, we stimulated transduced lumbar neurons after thoracic SCI by intraperitoneal application of CTZ, allowing for a less invasive treatment. The efficacy of this non-invasive BioLuminescent-OptoGenetic approach was confirmed by improved locomotor function. This study demonstrates that peripheral delivery of the luciferin CTZ can be used to activate LMOs expressed in spinal cord neurons that employ an opsin with increased light sensitivity.

Wien effect in interfacial water dissociation through proton-permeable graphene electrodes.

Strong electric fields can accelerate molecular dissociation reactions. The phenomenon known as the Wien effect was previously observed using high-voltage electrolysis cells that produced fields of about 107 V m-1, sufficient to accelerate the dissociation of weakly bound molecules (e.g., organics and weak electrolytes). The observation of the Wien effect for the common case of water dissociation (H2O [Formula: see text] H+ + OH-) has remained elusive. Here we study the dissociation of interfacial water adjacent to proton-permeable graphene electrodes and observe strong acceleration of the reaction in fields reaching above 108 V m-1. The use of graphene electrodes allows measuring the proton currents arising exclusively from the dissociation of interfacial water, while the electric field driving the reaction is monitored through the carrier density induced in graphene by the same field. The observed exponential increase in proton currents is in quantitative agreement with Onsager's theory. Our results also demonstrate that graphene electrodes can be valuable for the investigation of various interfacial phenomena involving proton transport.

Students in a Course-Based Undergraduate Research Experience Course Discovered Dramatic Changes in the Bacterial Community Composition Between Summer and Winter Lake Samples.

Course-based undergraduate research experience (CURE) courses incorporate high-impact pedagogies that have been shown to increase undergraduate retention among underrepresented minorities and women. As part of the Building Infrastructure Leading to Diversity program at the University of Detroit Mercy, a CURE metagenomics course was established in the winter of 2019. Students investigated the bacterial community composition in a eutrophic cove in Lake Saint Clair (Harrison Township, MI, United States) from water samples taken in the summer and winter. The students created 16S rRNA libraries that were sequenced using next-generation sequencing technology. They used a public web-based supercomputing resource to process their raw sequencing data and web-based tools to perform advanced statistical analysis. The students discovered that the most common operational taxonomic unit, representing 31% of the prokaryotic sequences in both summer and winter samples, corresponded to an organism that belongs to a previously unidentified phylum. This result showed the students the power of metagenomics because the approach was able to detect unclassified organisms. Principal Coordinates Analysis of Bray-Curtis dissimilarity index data showed that the winter community was distinct from the summer community [Analysis of Similarities (ANOSIM) r = 0.59829, n = 18, and p < 0.001]. Dendrograms based on hierarchically clustered Pearson correlation coefficients of phyla were divided into a winter clade and a summer clade. The conclusion is that the winter bacterial population was fundamentally different from the summer population, even though the samples were taken from the same locations in a protected cove. Because of the small class sizes, qualitative as well as statistical methods were used to evaluate the course's impact on student attitudes. Results from the Laboratory Course Assessment Survey showed that most of the respondents felt they were contributing to scientific knowledge and the course fostered student collaboration. The majority of respondents agreed or strongly agreed that the course incorporated iteration aspects of scientific investigations, such as repeating procedures to fix problems. In summary, the metagenomics CURE course was able to add to scientific knowledge and allowed students to participate in authentic research.

Image memorability is predicted by discriminability and similarity in different stages of a convolutional neural network.

The features of an image can be represented at multiple levels-from its low-level visual properties to high-level meaning. What drives some images to be memorable while others are forgettable? We address this question across two behavioral experiments. In the first, different layers of a convolutional neural network (CNN), which represent progressively higher levels of features, were used to select the images that would be shown to 100 participants through a form of prospective assignment. Here, the discriminability/similarity of an image with others, according to different CNN layers dictated the images presented to different groups, who made a simple indoor versus outdoor judgment for each scene. We found that participants remember more scene images that were selected based on their low-level discriminability or high-level similarity. A second experiment replicated these results in an independent sample of 50 participants, with a different order of postencoding tasks. Together, these experiments provide evidence that both discriminability and similarity, at different visual levels, predict image memorability.

Risk of repetition and subsequent self-harm following presentation to hospital with suicidal ideation: A longitudinal registry study.

BACKGROUND: Few studies have focused on those who present to hospital with suicidal thoughts (suicidal ideation). The aim of this study was to establish the risk of repeat presentation to hospital following suicidal ideation and to identify factors which were associated with further ideation or subsequent self-harm. METHODS: Data were obtained from the Northern Ireland Registry of Self-harm. Risk of repeat presentation following hospital-presenting ideation was analysed using Kaplan Meier analyses, specifically cox proportional hazard models. FINDINGS: During the period April 2014 to March 2019, a total of 14,695 presentations to hospital due to suicidal ideation were made in Northern Ireland. The cumulative incidence of repeat presentation to hospital was 40·5% within five years, with an 18·3% risk of subsequent self-harm. Previous ideation had the strongest association with repeat presentation. There was evidence of recidivism considering further ideation, with an increased risk according to number of previous presentations. In contrast, risk of subsequent self-harm was highest after the first or second presentation. Male gender and alcohol were associated with further ideation, while females and young people were more likely to re-present with self-harm. INTERPRETATION: The findings indicate that individuals who present to hospital with suicidal ideation are at risk of repeat presentation and future self-harm, however clinical guidelines do not specifically address hospital-presenting ideation. The transition from ideation to suicidal behaviour is important to consider and research could inform effective screening and early intervention measures. ROLE OF FUNDING: The Northern Ireland Registry of Self-harm is funded by the Public Health Agency, Northern Ireland.

Influences on memory for naturalistic visual episodes: sleep, familiarity, and traits differentially affect forms of recall.

The memories we form are composed of information that we extract from multifaceted episodes. Static stimuli and paired associations have proven invaluable stimuli for understanding memory, but real-life events feature spatial and temporal dimensions that help form new retrieval paths. We ask how the ability to recall semantic, temporal, and spatial aspects (the "what, when, and where") of naturalistic episodes is affected by three influences-prior familiarity, postencoding sleep, and individual differences-by testing their influence on three forms of recall: cued recall, free recall, and the extent that recalled details are recombined for a novel prompt. Naturalistic videos of events with rare animals were presented to 115 participants, randomly assigned to receive a 12- or 24-h delay with sleep and/or wakefulness. Participants' immediate and delayed recall was tested and coded by its spatial, temporal, and semantic content. We find that prior familiarity with items featured in events improved cued recall, but not free recall, particularly for temporal and spatial details. In contrast, postencoding sleep, relative to wakefulness, improved free recall, but not cued recall, of all forms of content. Finally, individuals with higher trait scores in the Survey of Autobiographical Memory spontaneously incorporated more spatial details during free recall, and more event details (at a trend level) in a novel recombination recall task. These findings show that prior familiarity, postencoding sleep, and memory traits can each enhance a different form of recall. More broadly, this work highlights that recall is heterogeneous in response to different influences on memory.

Complete Genome Sequences of Cluster G Mycobacteriophage Darionha, Cluster A Mycobacteriophage Salz, and Cluster J Mycobacteriophage ThreeRngTarjay.

Mycobacteriophages Darionha, Salz, and ThreeRngTarjay are mycobacteriophages isolated using the host Mycobacterium smegmatis mc2155. Following isolation from soil samples, all three siphoviridae phages were characterized, and their genomes were sequenced and annotated.

Neural Patterns are More Similar across Individuals during Successful Memory Encoding than during Failed Memory Encoding.

After experiencing the same episode, some people can recall certain details about it, whereas others cannot. We investigate how common (intersubject) neural patterns during memory encoding influence whether an episode will be subsequently remembered, and how divergence from a common organization is associated with encoding failure. Using functional magnetic resonance imaging with intersubject multivariate analyses, we measured brain activity as people viewed episodes within wildlife videos and then assessed their memory for these episodes. During encoding, greater neural similarity was observed between the people who later remembered an episode (compared with those who did not) within the regions of the declarative memory network (hippocampus, posterior medial cortex [PMC], and dorsal Default Mode Network [dDMN]). The intersubject similarity of the PMC and dDMN was episode-specific. Hippocampal encoding patterns were also more similar between subjects for memory success that was defined after one day, compared with immediately after retrieval. The neural encoding patterns were sufficiently robust and generalizable to train machine learning classifiers to predict future recall success in held-out subjects, and a subset of decodable regions formed a network of shared classifier predictions of subsequent memory success. This work suggests that common neural patterns reflect successful, rather than unsuccessful, encoding across individuals.

Review of external referrals to a regional stroke centre: it is not just about thrombectomy.

AIMS: To determine the experience of a regional stroke referral centre of external referrals for endovascular thrombectomy (EVT) in patients with symptoms of acute ischaemic stroke (AIS) and large vessel occlusion (LVO). MATERIALS AND METHODS: Data were collected prospectively over two 4-month periods (2017-2018) on consecutive external referrals for EVT. Baseline demographics, imaging findings, and key time parameters were recorded. Reasons for not transferring patients and for not performing EVT were recorded. Key time intervals were calculated and compared between the transferred and non-transferred group with and without intracranial occlusion and between the transferred patients who underwent thrombectomy and those who did not. RESULTS: Two hundred and sixty-two patients were referred. Sixty-one percent (n=159) were accepted and transferred for treatment. Of those transferred, 86% (n=136) had EVT. Fourteen percent (n=23) were unsuitable for EVT on arrival due to no vessel occlusion (48% n=11), poor Alberta Stroke Program Early CT Score (ASPECTS)/established infarct (30%, n=7) haemorrhage (9%, n=2), and clinical recovery (13% n=3). One hundred and three patients (39%) were ineligible for EVT following phone discussion due to absence of intracranial occlusion (59%, n=61), low ASPECTS (22%, n=23), distal occlusion (4%, n=4), low/improving National Institutes of Health Stroke Scale (NIHSS; 10.7%, n=11), and poor modified Rankin Scale (mRS) at baseline (3%, n=3). Patients with LVO but not transferred had longer onset to hospital arrival time compared with those transferred 151.5 versus 91 minutes (p<0.005), with a trend also toward a longer door to CT/CTA 40 minutes versus 30 minutes (p=0.142). CONCLUSION: These data provide valuable insights into the service provision of a comprehensive stroke network. The present rates of EVT and futile transfers are modest compared to published data. Access to neuroradiology and specialised stroke assessment is crucial to optimise time to treatment.

Psychosocial, psychiatric and work-related risk factors associated with suicide in Ireland: optimised methodological approach of a case-control psychological autopsy study.

BACKGROUND: Suicide has profound effects on families and communities, but is a statistically rare event. Psychological autopsies using a case-control design allow researchers to examine risk factors for suicide, using a variety of sources to detail the psychological and social characteristics of decedents and to compare them to controls. The Suicide Support and Information System Case Control study (SSIS-ACE) aimed to compare psychosocial, psychiatric and work-related risk factors across three groups of subjects: suicide decedents, patients presenting to hospital with a high-risk self-harm episode, and general practice controls. METHODS: The study design includes two inter-related studies; one main case-control study: comparing suicide cases to general practice (GP) controls, and one comparative study: comparing suicide cases to patients presenting with high-risk self-harm. Consecutive cases of suicide and probable suicide are identified through coroners' registration of deaths in the defined region (Cork City and County, Ireland) and are frequency-matched for age group and gender with GP patient controls recruited from the same GP practice as the deceased. Data sources for suicide cases include coroners' records, interviews with health care professionals and proxy informants; data sources for GP controls and for high-risk self-harm controls include interviews with control, with proxy informants and with health care professionals. Interviews are semi-structured and consist of quantitative and qualitative parts. The quantitative parts include a range of validated questionnaires addressing psychiatric, psychosocial and occupational factors. The study adopts several methodological innovations, including accessing multiple data sources for suicide cases and controls simultaneously, recruiting proxy informants to examine consistency across sources. CONCLUSIONS: The study allows for the investigation of consistency across different data sources and contributes to the methodological advancement of psychological autopsy research. The study will also inform clinical and public health practice. The comparison between suicide cases and controls will allow investigation of risk and protective factors for suicide more generally, while the comparison with high-risk self-harm patients will help to identify the factors associated specifically with a fatal outcome to a self-harm episode. A further enhancement is the particular focus on specific work-related risk factors for suicide.

A Standardized Aspiration-First Approach for Thrombectomy to Increase Speed and Improve Recanalization Rates.

BACKGROUND AND PURPOSE: Direct aspiration is a recognized technique for revascularization in large-vessel ischemic strokes. There is ongoing debate regarding its efficacy compared with stent retrievers. Every delay in achieving revascularization and a decrease in reperfusion rates reduces the likelihood of patients achieving functional independence. We propose a standardized setup technique for aspiration-first for all anterior circulation thrombectomy procedures for increasing speed and recanalization rates. MATERIALS AND METHODS: We analyzed 127 consecutive patients treated by a standardized approach to thrombectomy with an intention to perform aspiration-first compared with 127 consecutive patients treated with a stent retriever-first approach. Key time metrics evaluated included groin to first angiogram, first angiogram to reperfusion, groin to first reperfusion, and length of the procedure. The degree of successful recanalization (TICI 2b-3) and the number of passes were compared between the 2 groups. RESULTS: In 127 patients who underwent the standardized technique, the median time from groin puncture to first reperfusion was 18 minutes compared with 26 minutes (P < .001). The duration of the procedure was shorter compared with the stent retriever group (26 minutes in the aspiration first group versus 47 minutes, P < .001) and required fewer passes (mean, 2.4 versus 3.1; P < .05). A higher proportion of patients had a TICI score of 2b-3 in the aspiration-first group compared with stent retriever group (96.1% versus 85.8%, P < .005). CONCLUSIONS: Our study highlights the increasing speed and recanalization rates achieved with fewer passes in a standardized approach to thrombectomy with an intention to attempt aspiration-first. Any attempt to reduce revascularization time and increase successful recanalization should be used.

Semantic knowledge influences whether novel episodic associations are represented symmetrically or asymmetrically.

We provide new evidence concerning two opposing views of episodic associations: The independent-association hypothesis posits that associations are unidirectional and separately modifiable links (A→B and A←B); in contrast, the associative-symmetry hypothesis proposes that a single, bidirectional association exists between A and B (A↔B). We used a novel method to demonstrate that whether or not episodic associations are symmetric depends on whether there is a preexisting semantic relationship between A and B. In two experiments, participants studied 30 semantically unrelated and 30 semantically related pairs intermixed in a single list and then performed a series of up to eight cued-recall test cycles. All pairs were tested in each cycle, and the testing direction (A-? or B-?) alternated between cycles. Unrelated pairs exhibited associative symmetry-that is, accuracy and response times improved gradually on each test-suggesting that testing in both directions strengthened the same association. In contrast, semantically related pairs exhibited a stair-like pattern, in which performance did not change from odd to even tests when the test direction changed; it only improved between tests in the same direction. We concluded that episodic associations can have either a single bidirectional representation or separate directional representations, depending on the semantic relatedness of their constituent items.

A quantitative analysis of CT angiography, large vessel occlusion, and thrombectomy rates in acute ischaemic stroke.

AIMS: To determine the workload of acute computed tomography angiography (CTA) in patients presenting with suspected acute ischaemic stroke (AIS) and rate of large vessel occlusion (LVO) and thrombectomy relative to suspected and confirmed stroke diagnoses across three stroke centres within the Republic of Ireland. MATERIALS AND METHODS: A retrospective review of data from three stroke centres, one of which provides a 24-hour thrombectomy service was undertaken. The number of CTA studies performed from January 2015 to December 2017 for suspected AIS was quantified using the national PACS in addition to occlusion location, collateral status, and rates of LVO and thrombectomy. The hospital inpatient enquiry (HIPE) system was searched for all patients with a primary discharge diagnosis of stroke and then correlated with patients who underwent CTA on admission. RESULTS: A total of 2,358 CTA studies were performed for suspected AIS during the study period across three stroke centres. LVO was demonstrated in 18.4% of suspected AIS, 18.4% of primary discharge stroke diagnoses, and 40.2% of confirmed AIS who underwent CTA. A total of 283 thrombectomies were performed of which 64.6% were LVO. Thrombectomy was performed in 12% of suspected AIS, 12% of overall primary discharge diagnoses of stroke cases, and 26% of confirmed stroke who underwent CTA. CONCLUSION: Establishing the volume of acute CTAs and rates of LVO and thrombectomy when compared to suspected AIS on admission, confirmed stroke diagnoses who underwent CTA and primary discharge diagnosis of stroke is essential for the planning and provision of stroke services worldwide.