Deep Learning using K-space Based Data Augmentation for Automated Cardiac MR Motion Artefact Detection

Quality assessment of medical images is essential for complete automation of image processing pipelines. For large population studies such as the UK Biobank, artefacts such as those caused by heart motion are problematic and manual identification is tedious and time-consuming. Therefore, there is an urgent need for automatic image quality assessment techniques. In this paper, we propose a method to automatically detect the presence of motion-related artefacts in cardiac magnetic resonance (CMR) images. As this is a highly imbalanced classification problem (due to the high number of good quality images compared to the low number of images with motion artefacts), we propose a novel k-space based training data augmentation approach in order to address this problem. Our method is based on 3D spatio-temporal Convolutional Neural Networks, and is able to detect 2D+time short axis images with motion artefacts in less than 1ms. We test our algorithm on a subset of the UK Biobank dataset consisting of 3465 CMR images and achieve not only high accuracy in detection of motion artefacts, but also high precision and recall. We compare our approach to a range of state-of-the-art quality assessment methods.Comment: Accepted for MICCAI2018 Conferenc

Hepatic encephalopathy: Novel insights into classification, pathophysiology and therapy

Hepatic encephalopathy (HE) is a frequent and serious complication of both chronic liver disease and acute liver failure. HE manifests as a wide spectrum of neuropsychiatric abnormalities, from subclinical changes (mild cognitive impairment) to marked disorientation, confusion and coma. The clinical and economic burden of HE is considerable, and it contributes greatly to impaired quality of life, morbidity and mortality. This review will critically discuss the latest classification of HE, as well as the pathogenesis and pathophysiological pathways underlying the neurological decline in patients with end-stage liver disease. In addition, management strategies, diagnostic approaches, currently available therapeutic options and novel treatment strategies are discussed

SURF1 knockout cloned pigs: early onset of a severe lethal phenotype

Leigh syndrome (LS) associated with cytochrome c oxidase (COX) deficiency is an early onset, fatal mitochondrial encephalopathy, leading to multiple neurological failure and eventually death, usually in the first decade of life. Mutations in SURF1, a nuclear gene encoding a mitochondrial protein involved in COX assembly, are among the most common causes of LS. LSSURF1 patients display severe, isolated COX deficiency in all tissues, including cultured fibroblasts and skeletal muscle. Recombinant, constitutive SURF1−/− mice show diffuse COX deficiency, but fail to recapitulate the severity of the human clinical phenotype. Pigs are an attractive alternative model for human diseases, because of their size, as well as metabolic, physiological and genetic similarity to humans. Here, we determined the complete sequence of the swine SURF1 gene, disrupted it in pig primary fibroblast cell lines using both TALENs and CRISPR/Cas9 genome editing systems, before finally generating SURF1−/− and SURF1−/+ pigs by Somatic Cell Nuclear Transfer (SCNT). SURF1−/− pigs were characterized by failure to thrive, muscle weakness and highly reduced life span with elevated perinatal mortality, compared to heterozygous SURF1−/+ and wild type littermates. Surprisingly, no obvious COX deficiency was detected in SURF1−/− tissues, although histochemical analysis revealed the presence of COX deficiency in jejunum villi and total mRNA sequencing (RNAseq) showed that several COX subunit-encoding genes were significantly down-regulated in SURF1−/− skeletal muscles. In addition, neuropathological findings, indicated a delay in central nervous system development of newborn SURF1−/− piglets. Our results suggest a broader role of sSURF1 in mitochondrial bioenergetics

The effects of maintenance schedules following pulmonary rehabilitation in patients with chronic obstructive pulmonary disease: a randomised controlled trial.

OBJECTIVES: Pulmonary rehabilitation (PR) provides benefit for patients with chronic obstructive pulmonary disease (COPD) in terms of quality of life (QoL) and exercise capacity; however, the effects diminish over time. Our aim was to evaluate a maintenance programme for patients who had completed PR. SETTING: Primary and secondary care PR programmes in Norfolk. PARTICIPANTS: 148 patients with COPD who had completed at least 60% of a standard PR programme were randomised and data are available for 110 patients. Patients had greater than 20 pack year smoking history and less than 80% predicted forced expiratory volume in 1 s but no other significant disease or recent respiratory tract infection. INTERVENTIONS: Patients were randomised to receive a maintenance programme or standard care. The maintenance programme consisted of 2 h (1 h individually tailored exercise training and 1 h education programme) every 3 months for 1 year. PRIMARY AND SECONDARY OUTCOME MEASURES: The Chronic Respiratory Questionnaire (CRQ) (primary outcome), endurance shuttle walk test (ESWT), EuroQol (EQ5D), hospital anxiety and depression score (HADS), body mass index (BMI), body fat, activity levels (overall score and activity diary) and exacerbations were assessed before and after 12 months. RESULTS: There was no statistically significant difference between the groups for the change in CRQ dyspnoea score (primary end point) at 12 months which amounted to 0.19 (-0.26 to 0.64) units or other domains of the CRQ. There was no difference in the ESWT duration (-10.06 (-191.16 to 171.03) seconds), BMI, body fat, EQ5D, MET-minutes, activity rating, HADS, exacerbations or admissions. CONCLUSIONS: A maintenance programme of three monthly 2 h sessions does not improve outcomes in patients with COPD after 12 months. We do not recommend that our maintenance programme is adopted. Other methods of sustaining the benefits of PR are required. TRIAL REGISTRATION NUMBER: NCT00925171.This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG-0408-16225). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.This is the final published version. It first appeared at http://bmjopen.bmj.com/content/5/3/e005921.full?g=w_thorax_open_tab

General practitioners’ perspectives on campaigns to promote rapid help-seeking behaviour at the onset of rheumatoid arthritis

Objective. To explore general practitioners’ (GPs’ ) perspectives on public health campaigns to encourage people with the early symptoms of rheumatoid arthritis (RA) to seek medical help rapidly. Design. Nineteen GPs participated in four semistructured focus groups. Focus groups were audio-recorded, transcribed verbatim, and analysed using thematic analysis. Results. GPs recognised the need for the early treatment of RA and identified that facilitating appropriate access to care was important. However, not all held the view that a delay in help seeking was a clinically significant issue. Furthermore, many were concerned that the early symptoms of RA were often non-specific, and that current knowledge about the nature of symptoms at disease onset was inadequate to inform the content of a help-seeking campaign. They argued that a campaign might not be able to specifically target those who need to present urgently. Poorly designed campaigns were suggested to have a negative impact on GPs’ workloads, and would “clog up” the referral pathway for genuine cases of RA. Conclusions. GPs were supportive of strategies to improve access to Rheumatological care and increase public awareness of RA symptoms. However, they have identified important issues that need to be considered in developing a public health campaign that forms part of an overall strategy to reduce time to treatment for patients with new onset RA. This study highlights the value of gaining GPs’ perspectives before launching health promotion campaigns

Controlling hypertension immediately post stroke: a cost utility analysis of a pilot randomised controlled trial.

BACKGROUND: Elevated blood pressure (BP) levels are common following acute stroke. However, there is considerable uncertainty if and when antihypertensive therapy should be initiated. METHOD: Economic evaluation alongside a double-blind randomised placebo-controlled trial (National Research Register Trial Number N0484128008) of 112 hypertensive patients receiving an antihypertensive regimen (labetalol or lisinopril) within 36 hours post stroke versus 59 receiving placebo. Outcomes were incremental cost per incremental: QALY, survivor, and patient free from death or severe disability (modified Rankin scale score < 4) at three months and 14 days post stroke. RESULTS: Actively treated patients on average had superior outcomes and lower costs than controls at three months. From the perspective of the acute hospital setting, there was a 96.5% probability that the incremental cost per QALY gained at three months is below pound30,000, although the probability may be overstated due to data limitations. CONCLUSION: Antihypertensive therapy when indicated immediately post stroke may be cost-effective compared with placebo from the acute hospital perspective. Further research is required to confirm both efficacy and cost-effectiveness and establish whether benefits are maintained over a longer time horizon

A systematic review of randomised controlled trials on the effectiveness of exercise programs on lumbo pelvic pain among postnatal women

Background: A substantial number of women tend to be affected by Lumbo Pelvic Pain (LPP) following child birth. Physical exercise is indicated as a beneficial method to relieve LPP, but individual studies appear to suggest mixed findings about its effectiveness. This systematic review aimed to synthesise evidence from randomised controlled trials on the effectiveness of exercise on LPP among postnatal women to inform policy, practice and future research. Methods: A systematic review was conducted of all randomised controlled trials published between January 1990 and July 2014, identified through a comprehensive search of following databases: PubMed, PEDro, Embase, Cinahl, Medline, SPORTDiscus, Cochrane Pregnancy and Childbirth Group’s Trials Register, and electronic libraries of authors’institutions. Randomised controlled trials were eligible for inclusion if the intervention comprised of postnatal exercise for women with LPP onset during pregnancy or within 3 months after delivery and the outcome measures included changes in LPP. Selected articles were assessed using the PEDro Scale for methodological quality and findings were synthesised narratively as meta-analysis was found to be inappropriate due to heterogeneity among included studies. Results: Four randomised controlled trials were included, involving 251 postnatal women. Three trials were rated as of ‘good’ methodological quality. All trials, except one, were at low risk of bias. The trials included physical exercise programs with varying components, differing modes of delivery, follow up times and outcome measures. Intervention in one trial, involving physical therapy with specific stabilising exercises, proved to be effective in reducing LPP intensity. An improvement in gluteal pain on the right side was reported in another trial and a significant difference in pain frequency in another. Conclusion: Our review indicates that only few randomised controlled trials have evaluated the effectiveness of exercise on LPP among postnatal women. There is also a great amount of variability across existing trials in the components of exercise programs, modes of delivery, follow up times and outcome measures. While there is some evidence to indicate the effectiveness of exercise for relieving LPP, further good quality trials are needed to ascertain the most effective elements of postnatal exercise programs suited for LPP treatment

Methods for confidence interval estimation of a ratio parameter with application to location quotients

BACKGROUND: The location quotient (LQ) ratio, a measure designed to quantify and benchmark the degree of relative concentration of an activity in the analysis of area localization, has received considerable attention in the geographic and economics literature. This index can also naturally be applied in the context of population health to quantify and compare health outcomes across spatial domains. However, one commonly observed limitation of LQ is its widespread use as only a point estimate without an accompanying confidence interval. METHODS: In this paper we present statistical methods that can be used to construct confidence intervals for location quotients. The delta and Fieller's methods are generic approaches for a ratio parameter and the generalized linear modelling framework is a useful re-parameterization particularly helpful for generating profile-likelihood based confidence intervals for the location quotient. A simulation experiment is carried out to assess the performance of each of the analytic approaches and a health utilization data set is used for illustration. RESULTS: Both the simulation results as well as the findings from the empirical data show that the different analytical methods produce very similar confidence limits for location quotients. When incidence of outcome is not rare and sample sizes are large, the confidence limits are almost indistinguishable. The confidence limits from the generalized linear model approach might be preferable in small sample situations. CONCLUSION: LQ is a useful measure which allows quantification and comparison of health and other outcomes across defined geographical regions. It is a very simple index to compute and has a straightforward interpretation. Reporting this estimate with appropriate confidence limits using methods presented in this paper will make the measure particularly attractive for policy and decision makers

MICRO-Foundations in Strategic Management: Squaring Coleman's Diagram

Abell, Felin and Foss argue that "macro-explanations" in strategic management, explanations in which organizational routines figure prominently and in which both the explanandum and explanans are at the macro-level, are necessarily incomplete. They take a diagram (which has the form of a trapezoid) from Coleman, Foundations of Social Theory, The Belknap Press of Harvard University Press, Cambridge (Mass.)/London, (1990) to task to show that causal chains connecting two macro-phenomena always involve "macro-to-micro" and "micro-to-macro" links, links that macro-explanations allegedly fail to recognize. Their plea for micro-foundations in strategic management is meant to shed light on these "missing links". The paper argues that while there are good reasons for providing micro-foundations, Abell, Felin and Foss's causal incompleteness argument is not one of them. Their argument does not sufficiently distinguish between causal and constitutive relations. Once these relations are carefully distinguished, it follows that Coleman's diagram has to be squared. This in turn allows us to see that macro-explanations need not be incomplete

A resting state network in the motor control circuit of the basal ganglia

<p>Abstract</p> <p>Background</p> <p>In the absence of overt stimuli, the brain shows correlated fluctuations in functionally related brain regions. Approximately ten largely independent resting state networks (RSNs) showing this behaviour have been documented to date. Recent studies have reported the existence of an RSN in the basal ganglia - albeit inconsistently and without the means to interpret its function. Using two large study groups with different resting state conditions and MR protocols, the reproducibility of the network across subjects, behavioural conditions and acquisition parameters is assessed. Independent Component Analysis (ICA), combined with novel analyses of temporal features, is applied to establish the basis of signal fluctuations in the network and its relation to other RSNs. Reference to prior probabilistic diffusion tractography work is used to identify the basal ganglia circuit to which these fluctuations correspond.</p> <p>Results</p> <p>An RSN is identified in the basal ganglia and thalamus, comprising the pallidum, putamen, subthalamic nucleus and substantia nigra, with a projection also to the supplementary motor area. Participating nuclei and thalamo-cortical connection probabilities allow this network to be identified as the motor control circuit of the basal ganglia. The network was reproducibly identified across subjects, behavioural conditions (fixation, eyes closed), field strength and echo-planar imaging parameters. It shows a frequency peak at 0.025 ± 0.007 Hz and is most similar in spectral composition to the Default Mode (DM), a network of regions that is more active at rest than during task processing. Frequency features allow the network to be classified as an RSN rather than a physiological artefact. Fluctuations in this RSN are correlated with those in the task-positive fronto-parietal network and anticorrelated with those in the DM, whose hemodynamic response it anticipates.</p> <p>Conclusion</p> <p>Although the basal ganglia RSN has not been reported in most ICA-based studies using a similar methodology, we demonstrate that it is reproducible across subjects, common resting state conditions and imaging parameters, and show that it corresponds with the motor control circuit. This characterisation of the basal ganglia network opens a potential means to investigate the motor-related neuropathologies in which the basal ganglia are involved.</p