70 research outputs found
Dynamic Susceptibility Contrast MRI May Contribute in Prediction of Stereotactic Radiosurgery Outcome in Brain Metastases
Background
Following stereotactic radiosurgery (SRS), predicting treatment response is not possible at an early stage using structural imaging alone. Hence, the current study aims at investigating whether dynamic susceptibility contrast (DSC)-MRI estimated prior to SRS can provide predictive biomarkers in response to SRS treatment and characterize vascular characteristics of pseudo-progression.
Methods
In this retrospective study, perfusion-weighted DSC-MRI image data acquired with a temporal resolution of 1.45 seconds were collected from 41 patients suffering from brain metastases. Outcome was defined based on lesion volume changes in time (determined on structural images) or death. Motion correction and manual lesion delineation were performed prior to semi-automated, voxel-wise perfusion analysis. Statistical testing was performed using linear regression and a significance threshold at Pâ
=â
.05. Age, sex, primary cancers (pulmonary cancer and melanoma), lesion volume, and dichotomized survival time were added as covariates in the linear regression models (ANOVA).
Results
Relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) were found to be significantly lower prior to SRS treatment in patients with increasing lesion volume or early death post-SRS (Pâ
â¤â
.01).
Conclusion
Unfavorable treatment outcome may be linked to low perfusion prior to SRS. Pseudo-progression may be preceded by a transient rCBF increase post-SRS. However, results should be verified in different or larger patient material.publishedVersio
Improving Safety by Learning from Automation in Transport Systems with a Focus on Sensemaking and Meaningful Human Control
Automated transport systems are deployed in many areas and transport modes. The predominant engineering perspective has been to automate as much as possible and minimize human interaction. However, a balanced integration between human factors and technology is often missing, as well as the âhand-overâ process between humans and machine. The risks of automated and autonomous systems are emerging, and there is a need to explore how risks can be mitigated through design, focusing on sensemaking, meaningful human control and resilience engineering. This chapter presents key issues from an ongoing research project exploring safety, security and human control of autonomous transport systems in road, sea, rail and air. The chapter aims to answer: (1) What are the major safety and security challenges of autonomous industrial transport systems? (2) What can the various transport modes learn from each other? (3) What are suggested key measures related to organizational, technical and human issues? We have performed literature reviews, interviews and reviewed on-going automation projects. We see the importance of involving humans in the loop during design and operations, support sensemaking, focus on learning from projects through data gathering and risk-based regulation. Unanticipated deviations are key challenges in automated systems, together with how to design for humanâautomation interaction and meaningful user involvement. Limiting the operational envelope seems to be a key issue for successful implementation and operation of autonomous systems.publishedVersio
Impaired cerebrovascular reactivity may predict delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage
Introduction: Delayed cerebral ischemia (DCI) is a major cause of disability and death after aneurysmal subarachnoid hemorrhage. The literature suggests that impaired cerebrovascular reactivity (CVR) may be a predictor for DCI; still no CVR based prediction model has been developed. Increased knowledge about possible predictors of DCI can improve patient management in high-risk patients and allow for shorter hospital stay in low-risk patients. Method: CVR was examined in 42 patients with aneurysmal subarachnoid hemorrhage and 37 patients treated for unruptured intracranial aneurysm, using acetazolamide test with transcranial Doppler monitoring of blood flow velocities. Patients were followed for development of DCI, separated into clinical deterioration and radiographic infarction. Results: For all patients, regardless of aneurysm rupture status, CVR was on average 5.5 percentage points lower on the ipsilateral side of aneurysm treatment. Patients with clinical deterioration due to DCI had lower CVR than patients without DCI, and the difference was larger on the contralateral side (33.9% vs. 49.2%). Two prediction models were constructed for clinical deterioration due to DCI. The area under the receiver operating characteristic curve was 0.82 in the model using established predictors, and 0.86 in the model that also included CVR. Conclusion: Our findings support the hypothesis that impaired CVR may be an independent predictor of clinical deterioration due to DCI, and may assist in identifying patients at risk after aneurysmal subarachnoid hemorrhage. Ipsilateral CVR reduction occurs in all patients after aneurysm treatment, regardless of DCI development, thus highlighting the need to evaluate ipsi- and contralateral CVR separately.publishedVersio
Spinous Process Osteotomy to Facilitate the Access to the Spinal Canal When Decompressing the Spinal Canal in Patients with Lumbar Spinal Stenosis
Study DesignRetrospective study.PurposeThe main purpose of this study was to investigate the union-rate of the spinous process after performing a spinous process osteotomy and whether union affects the clinical results after surgery.Overview of LiteratureIn the present study, spinous process osteotomy was used to facilitate access to the spinal canal when performing a decompressive procedure for lumbar spinal stenosis. The aim of this study was to evaluate the union rate of the spinous process and its effect on the clinical results of the procedure.MethodsAll patients were included in the study that underwent a decompressive procedure through spinous process osteotomy be between January 1, 2007 and December 31, 2007. Operation protocols were reviewed. A computed tomography (CT) scan was performed to evaluate the union of the osteotomies of the spinous process. According to the CT-scans, patients were divided into three groups: "complete-union," "partial-union," and "non-union." Patients reported their clinical results through a self-administered questionnaire.ResultsThe mean period of follow up was 21.6 months (range, 16-28 months). A total of 44% of the performed osteotomies were considered as united. Ten patients (18%) were classified as "complete-union," 30 patients (55%) as "partial-union," and 15 patients (27%) as "non-union." The "complete-union" group showed better clinical results and scored significantly better in the Oswestry Disability Index and EQ-5D. However, no statistical difference was found in the pain-scores. There were no differences between the "partial-union" group and the "no-union" group.ConclusionsWe found a radiologic union for 60 out of 135 (44%) spinous process osteotomies
Behavioral reactions of brown bears to approaching humans in Fennoscandia
Human disturbance causes behavioral responses in wildlife, including large carnivores. Previous research in Scandinavia has documented that brown bears (Ursus arctos) show a variety of behavioral reactions to different human activities. We investigated how proximity to human settlements and roads, as proxies of human influence, affected brown bears' reactions to encountering humans. We analyzed experimental approaches to GPS collared bears, 18 males and 23 single females, in Sweden (n = 148 approaches) and Finland (n = 33), conducted between 2004 and 2012. The bears in Finland inhabited areas with higher human density compared to Sweden. However, the proportion of bears staying or moving when approached and the flight initiation distances were similar in both countries. In Sweden, the flight responses were not dependent on human densities or roads inside the bears' home ranges or the distances from the bears to roads and settlements. Brown bears in Fennoscandia live in areas with relatively low human population densities, but in many areas with high forestry road densities. Our results show that bears' flight reactions were consistent between areas, which is an important message for management, reinforcing previous studies that have documented human avoidance by bears at different spatial and temporal scales.Peer reviewe
Clinical presentation and diffusion weighted MRI of acute cerebral infarction. The Bergen Stroke Study
Factors accounting for the association between anxiety and depression, and eczema: the Hordaland health study (HUSK)
<p>Abstract</p> <p>Background</p> <p>The association between anxiety and depression, and eczema is well known in the literature, but factors underlying this association remain unclear. Low levels of omega-3 fatty acids and female gender have been found to be associated with both depression and eczema. Somatization and health anxiety are known to be associated with anxiety and depression, further, somatization symptoms and health anxiety have also been found in several dermatological conditions. Accordingly, omega-3 fatty acid supplement, female gender, somatization and health anxiety are possible contributing factors in the association between anxiety and depression, and eczema. The aim of the study is to examine the relevance of proposed contributing factors for the association between anxiety and depression, and eczema, including, omega-3 fatty acid supplement, female gender, health anxiety and somatization.</p> <p>Methods</p> <p>Anxiety and depression was measured in the general population (n = 15715) employing the Hospital Anxiety and Depression Scale (HADS). Information on eczema, female gender, omega-3 fatty acid supplement, health anxiety and somatization was obtained by self-report.</p> <p>Results</p> <p>Somatization and health anxiety accounted for more than half of the association between anxiety/depression, and eczema, while the other factors examined were of minor relevance for the association of interest.</p> <p>Conclusions</p> <p>We found no support for female gender and omega-3 fatty acid supplement as contributing factors in the association between anxiety/depression, and eczema. Somatization and health anxiety accounted for about half of the association between anxiety/depression, and eczema, somatization contributed most. The association between anxiety/depression, and eczema was insignificant after adjustment for somatization and health anxiety. Biological mechanisms underlying the mediating effect of somatization are yet to be revealed.</p
Behaviour of Solitary Adult Scandinavian Brown Bears (Ursus arctos) when Approached by Humans on Foot
Successful management has brought the Scandinavian brown bear (Ursus arctos L.) back from the brink of extinction, but as the population grows and expands the probability of bear-human encounters increases. More people express concerns about spending time in the forest, because of the possibility of encountering bears, and acceptance for the bear is decreasing. In this context, reliable information about the bear's normal behaviour during bear-human encounters is important. Here we describe the behaviour of brown bears when encountering humans on foot. During 2006â2009, we approached 30 adult (21 females, 9 males) GPS-collared bears 169 times during midday, using 1-minute positioning before, during and after the approach. Observer movements were registered with a handheld GPS. The approaches started 869Âą348 m from the bears, with the wind towards the bear when passing it at approximately 50 m. The bears were detected in 15% of the approaches, and none of the bears displayed any aggressive behaviour. Most bears (80%) left the initial site during the approach, going away from the observers, whereas some remained at the initial site after being approached (20%). Young bears left more often than older bears, possibly due to differences in experience, but the difference between ages decreased during the berry season compared to the pre-berry season. The flight initiation distance was longer for active bears (115Âą94 m) than passive bears (69Âą47 m), and was further affected by horizontal vegetation cover and the bear's age. Our findings show that bears try to avoid confrontations with humans on foot, and support the conclusions of earlier studies that the Scandinavian brown bear is normally not aggressive during encounters with humans
Effects of sheep grazing and temporal variability on population dynamics of the clonal herb Geranium sylvaticum in an alpine habitat
Trafikksikkerhet for automatiserte kjøretøy - SmartFeeder: Erfaringer fra norske piloter med selvkjørende minibusser
Vi presenterer her resultater fra fem norske pilotprosjekt i perioden 2018â2020 med automatiserte minibusser. Deretter settes resultatene inn i en bredere kontekst med oppdatert kunnskap fra litteraturundersøkelser (Stateâofâtheâart). Denne delen gir innblikk i status pĂĽ teknologi og trafikksikkerhet innen utvikling av automatiserte privatbiler og tilsvarende selvkjørende busser internasjonalt. Resultatene fra omfattende pilotering i Norge med selvkjørende minibusser viser at det tross betydelig eksponering i trafikk, ikke har vĂŚrt alvorlige hendelser. Det har det heller ikke vĂŚrt internasjonalt med denne typen selvkjørende minibusser med sikkerhetsoperatør ombord. Det er fremdeles svakheter ved teknologien. BĂĽde funksjonelle og trafikksikkerhetsmessige svakheter er avdekket i de norske pilotene og med tilsvarende minibusser internasjonalt. Det kommer ogsĂĽ frem av ulykker med kjøretøy pĂĽ SAE nivĂĽ 2â4 (Tesla, Uber, Google, AGV) som det er redegjort for i denne rapporten. Evnen til ĂĽ gjenkjenne objekter, forutse uventede situasjoner og samhandle med andre myke trafikanter og kjøretøy bør forbedres. For ĂĽ kompensere for disse svakhetene kan det i en overgangsfase vĂŚre fornuftig ĂĽ etablere et kontrollrom for overvĂĽkning og eventuelt gripe inn. Automatisering har skapt nye typer ulykker, men automatiserte kjøretøy kjører ikke i ruset tilstand, er ikke uoppmerksomme, søvnige, aggressive og de følger trafikkregler til punkt og prikke dersom trafikkreglene digitaliseres. Selv om de forĂĽrsaker noen nye ulykker, vil det skje en stadig forbedring av teknologien. PĂĽgĂĽende utvikling innen kunstig intelligens (AI) og lĂŚrende systemer vil vĂŚre viktig for ĂĽ heve dagens automatiserte kjøretøy opp pĂĽ et høyere nivĂĽ som tillater høyere hastigheter og bruk i alle typer trafikkmiljø.Automatiserte kjøretøy tar lĂŚrdompublishedVersio
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