Reproducibility of Liver Stiffness Measurement by Ultrasonographic Elastometry

Background & AimsFibroscan is a noninvasive device that assesses liver fibrosis by liver stiffness evaluation (LSE) with ultrasonographic elastometry. We evaluated LSE reproducibility and its influencing factors. Methods LSE was performed by 4 experienced physicians (>100 LSEs) in 46 patients with chronic liver disease at 4 different anatomic sites. Additional LSEs were performed for ancillary aims, so that 534 LSEs were available. Results Overall interobserver agreement for LSE results was considered as excellent, with intraclass coefficient correlation (Ric) of 0.93. Low LSE level, nonrecommended sites, LSE interquartile range > 25%, and body mass index ≥25 independently decreased agreement. Thus, agreement was fair (Ric = 0.53) for LSE < 9 kilopascals and excellent (Ric = 0.90) beyond. The best measurement site for LSE reproducibility was the median axillary line on the first intercostal space under the liver dullness upper limit, with the patient lying in dorsal decubitus. When LSE results were categorized into fibrosis Metavir stages, interobserver discordance was noticed in about 25% of the cases and was the highest for F2 and F3 stages and the lowest for F4. Intraobserver (Ric = 0.94), intersite (Ric = 0.92–0.98), and interequipment (Ric = 0.92) agreements for LSE results were excellent. Preliminary standard ultrasonography or probe pressure changes did not improve interobserver agreement. Conclusions The best measurement site for LSE is the one generally used for liver biopsy. Reproducibility of LSE is globally excellent but is fair in patient with low liver stiffness. The fibrosis diagnosis by ultrasonographic elastometry in low stages or categorized into fibrosis Metavir stages must be interpreted with caution

Learning curve and interobserver reproducibility evaluation of liver stiffness measurement by transient elastography:

Background/Aims: Fibroscan allows liver stiffness examination (LSE) that is well correlated with fibrosis stages. Our main objective was to evaluate LSE learning curve.Methods: LSE results of five novice observers with different medical status were compared with those of five expert observers (physicians with >100 examinations) in 250 patients with chronic liver disease. Each novice–expert pair had to blindly examine 50 consecutive patients divided into five consecutive subgroups of 10 patients. Results: In each observer group, novice–expert agreement [intraclass correlation coefficient (Ric)] for LSE results was excellent from the first to the last subgroup. Novice–expert agreement for LSE results varied with liver stiffness level: <9 kPa: Ric=0.49; ≥9 kPa: Ric=0.87. Relative difference (%) between novice and expert LSE results was independently associated with the number of valid LSE measurements, and stabilizes around 20–30% after the fourth valid measurement. In each observer group, novice–expert agreement (Ric) for LSE success rate progressively increased as a function of time. Conclusion: LSE requires no learning curve: a novice is able to obtain a reliable result after a single training session, whatever the professional status. However, success rate will progressively increase. An LSE with less than four valid measurements should not be considered as reliable

Robust averaging protects decisions from noise in neural computations

An ideal observer will give equivalent weight to sources of information that are equally reliable. However, when averaging visual information, human observers tend to downweight or discount features that are relatively outlying or deviant (‘robust averaging’). Why humans adopt an integration policy that discards important decision information remains unknown. Here, observers were asked to judge the average tilt in a circular array of high-contrast gratings, relative to an orientation boundary defined by a central reference grating. Observers showed robust averaging of orientation, but the extent to which they did so was a positive predictor of their overall performance. Using computational simulations, we show that although robust averaging is suboptimal for a perfect integrator, it paradoxically enhances performance in the presence of “late” noise, i.e. which corrupts decisions during integration. In other words, robust decision strategies increase the brain’s resilience to noise arising in neural computations during decision-making

Bilateral testicular self-castration due to cannabis abuse: a case report

<p>Abstract</p> <p>Introduction</p> <p>The self-mutilating patient is an unusual psychiatric presentation in the emergency room. Nonetheless, serious underlying psychiatric pathology and drug abuse are important background risk factors. A careful stepwise approach in the emergency room is essential, although the prognosis, follow-up, and eventual rehabilitation can be problematic.</p> <p>We present a unique and original case of bilateral self-castration caused by cannabis abuse.</p> <p>Case Presentation</p> <p>We report a case of a 40-year-old Berber man, who was presented to our emergency room with externalization of both testes using his long fingernails, associated with hemodynamic shock. After stabilization of his state, our patient was admitted to the operating room where hemostasis was achieved.</p> <p>Conclusion</p> <p>The clinical characteristics of self-mutilation are manifold and there is a lack of agreement about its etiology. The complex behavior associated with drug abuse may be one cause of self-mutilation. Dysfunction of the inhibitory brain circuitry caused by substance abuse could explain why this cannabis-addicted patient lost control and self-mutilated. To the best of our knowledge, this is the first case report which presents an association between self-castration and cannabis abuse.</p

Feasibility of a walking virtual reality system for rehabilitation: objective and subjective parameters

[EN] Background: Even though virtual reality (VR) is increasingly used in rehabilitation, the implementation of walking navigation in VR still poses a technological challenge for current motion tracking systems. Different metaphors simulate locomotion without involving real gait kinematics, which can affect presence, orientation, spatial memory and cognition, and even performance. All these factors can dissuade their use in rehabilitation. We hypothesize that a marker-based head tracking solution would allow walking in VR with high sense of presence and without causing sickness. The objectives of this study were to determine the accuracy, the jitter, and the lag of the tracking system and its elicited sickness and presence in comparison of a CAVE system. Methods: The accuracy and the jitter around the working area at three different heights and the lag of the head tracking system were analyzed. In addition, 47 healthy subjects completed a search task that involved navigation in the walking VR system and in the CAVE system. Navigation was enabled by natural locomotion in the walking VR system and through a specific device in the CAVE system. An HMD was used as display in the walking VR system. After interacting with each system, subjects rated their sickness in a seven-point scale and their presence in the Slater-Usoh-Steed Questionnaire and a modified version of the Presence Questionnaire. Results: Better performance was registered at higher heights, where accuracy was less than 0.6 cm and the jitter was about 6 mm. The lag of the system was 120 ms. Participants reported that both systems caused similar low levels of sickness (about 2.4 over 7). However, ratings showed that the walking VR system elicited higher sense of presence than the CAVE system in both the Slater-Usoh-Steed Questionnaire (17.6 +/- 0.3 vs 14.6 +/- 0.6 over 21, respectively) and the modified Presence Questionnaire (107.4 +/- 2.0 vs 93.5 +/- 3.2 over 147, respectively). Conclusions: The marker-based solution provided accurate, robust, and fast head tracking to allow navigation in the VR system by walking without causing relevant sickness and promoting higher sense of presence than CAVE systems, thus enabling natural walking in full-scale environments, which can enhance the ecological validity of VR-based rehabilitation applications.The authors wish to thank the staff of LabHuman for their support in this project, especially José Miguel Martínez and José Roda for their assistance. 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Dynamics and tensions of implementingagencification reforms: Experiences of DistrictDevelopment Authorities in Papua New Guinea

Agencification reforms aimed at reducing centralisedcontrol and enhancing efficiency by creating arm’s-length autonomous agencies. This paper examines thecreation of District Development Authorities (DDA)in Papua New Guinea (PNG). DDAs are typical agen-cification reforms seeking to empower local govern-ments with greater administrative and financial author-ity. Using a principal-agent framework, the experiencesof the two DDAs in East New Britain, Kokopo, andRabaul highlight some of the key challenges and strate-gies in implementing agencification reforms. Findingsof the study revealed that the DDAs in East New Britainadapted the new system while retaining some aspects ofthe older system, which helped in navigating throughthe structural changes and the multiple principal-agentrelationships. As a key component of agencification pro-cess, these DDAs have also started engaging in revenuegeneration activities. Such economic activities have thepotential to shift the dominant principal-agent relation-ship from the national to the local level

Ganoderma infection of oil palm – a persistent problem in Papua New Guinea and Solomon Islands

Basal stem rot (BSR) disease caused by Ganoderma boninense Pat. is a major limiting factor to palm oil producing countries in South East Asia, which produce 90% of the world’s palm oil demand. BSR has been known for over 100 years and to date continues to be a disease of increasing economic importance. Once considered a disease of senescing palms, BSR has persisted through successive replants, infecting younger plantings and shortening the economic life span of each cropping cycle. Many approaches have been applied to control BSR of oil palm with varying levels of success. To date, there is still no single approach that has been demonstrated to be effective in BSR management. The long-term strategy would be to breed genotypes resistant or tolerant to BSR. However, this is dependent on a multi-disciplinary approach to understanding oil palm-Ganoderma interactions that can reveal the mechanisms involved with infectivity and pathogenicity of Ganoderma, and susceptibility, resistance or tolerance of oil palm. This review aims to highlight the knowledge gaps that need addressing to improve the control and management of BSR

Time to act: New perspectives on embodiment and timing

Time perception may often be difficult to define in terms of processes and specific brain areas but it is ever-present in all aspects of our daily life. The study of timing has been central in Cognitive Sciences but recently research has been more vigorous extending from static and/or unimodal stimulations to moving and/or multimodal presentations. This symposium will focus on recent behavioral and neuroimaging work conducted with abstract moving and actual dance stimuli (enacted and observed) in relation to timing. The use of biological real or implied movement in timing research has made its appearance the last few years providing a new platform for the investigation of embodiment and timing. Research to-date has shown a distorted or enhanced time percept in the presence of a moving (actual, implied or apparent motion) as compared to a static stimulus, a fast as compared to a slow moving dancer (or crowd, objects etc.), an expert in terms of spatiotemporal training (e. g., dancer) as compared to a naive participant, to name just a few. The differential temporal percept observed has been attributed to different clock processes for moving vs. non-moving stimuli to the recruitment of additional processes due to embodiment (e. g., memory). However, more research is required in order to obtain a better understanding of the above-mentioned issues. Through this symposium we aim to bring more focus on this area of research and promote discussion on current findings and theories. (C) 2014 The Authors. Published by Elsevier Ltd