Social-Group-Optimization based tumor evaluation tool for clinical brain MRI of Flair/diffusion-weighted modality

Brain tumor is one of the harsh diseases among human community and is usually diagnosed with medical imaging procedures. Computed-Tomography (CT) and Magnetic-Resonance-Image (MRI) are the regularly used non-invasive methods to acquire brain abnormalities for medical study. Due to its importance, a significant quantity of image assessment and decision-making procedures exist in literature. This article proposes a two-stage image assessment tool to examine brain MR images acquired using the Flair and DW modalities. The combination of the Social-Group-Optimization (SGO) and Shannon's-Entropy (SE) supported multi-thresholding is implemented to pre-processing the input images. The image post-processing includes several procedures, such as Active Contour (AC), Watershed and region-growing segmentation, to extract the tumor section. Finally, a classifier system is implemented using ANFIS to categorize the tumor under analysis into benign and malignant. Experimental investigation was executed using benchmark datasets, like ISLES and BRATS, and also clinical MR images obtained with Flair/DW modality. The outcome of this study confirms that AC offers enhanced results compared with other segmentation procedures considered in this article. The ANFIS classifier obtained an accuracy of 94.51% on the used ISLES and real clinical images. (C) 2019 Nalecz Institute of Biocybernetics and Biomedical Engineering of the Polish Academy of Sciences

Deep learning-based post-processing of real-time MRI to assess and quantify dynamic wrist movement in health and disease

While morphologic magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of ligamentous wrist injuries, it is merely static and incapable of diagnosing dynamic wrist instability. Based on real-time MRI and algorithm-based image post-processing in terms of convolutional neural networks (CNNs), this study aims to develop and validate an automatic technique to quantify wrist movement. A total of 56 bilateral wrists (28 healthy volunteers) were imaged during continuous and alternating maximum ulnar and radial abduction. Following CNN-based automatic segmentations of carpal bone contours, scapholunate and lunotriquetral gap widths were quantified based on dedicated algorithms and as a function of wrist position. Automatic segmentations were in excellent agreement with manual reference segmentations performed by two radiologists as indicated by Dice similarity coefficients of 0.96 ± 0.02 and consistent and unskewed Bland–Altman plots. Clinical applicability of the framework was assessed in a patient with diagnosed scapholunate ligament injury. Considerable increases in scapholunate gap widths across the range-of-motion were found. In conclusion, the combination of real-time wrist MRI and the present framework provides a powerful diagnostic tool for dynamic assessment of wrist function and, if confirmed in clinical trials, dynamic carpal instability that may elude static assessment using clinical-standard imaging modalities

Mapping Genetic Influence on Brain Structure

Neuroimaging is playing an increasingly crucial role in delineating pathological conditions that cannot be typically defined by non-specific clinical symptom. The goal of this thesis was to characterize the genetic influence on grey and white matter indices and evaluate their potential as a reliable “structural MRI signatures”. We first assessed the effects of spatial resolution and smoothing on heritability estimation (Chapter 3). We then investigated heritability patterns of MRI measures of grey and white matter (Chapters 4-5). We then performed a cross-sectional evaluation of how heritability changes over the lifespan for both grey and white matter (Chapter 6). Finally, multivariate structural equation modeling was used to investigate the genetic correlation between grey matter structure and white matter connectivity (Chapter 7), in the default mode network (DMN). Our results show that several key brain structures were moderate to highly heritable and that this heritability was both spatially and temporally heterogeneous. At a network level, the DMN was found to have distinct genetic factors that modulated the grey matter regions and white matter tracts separately. We conclude that the spatial and temporal heterogeneity are likely to reflect gene expression patterns that are related to the developmental of specific brain regions and circuits over time

Repositioning Neuroaesthetics Through Contemporary Art

Neuroaesthetics has tended to privilege neuroscientific understandings of art, eliding centuries of art historical research on perception and culture. Instead, this dissertation extends neuroaesthetic research to examine the specific social, sensorial and perceptual processes occurring as artworks are encountered in exhibition contexts. How does neuroaesthetic perception operate in contemporary artworks? What modes of cognitive address are involved? How can neuroaesthetic engagement facilitate embodied knowledges? This dissertation first inquires into the neuroaesthetic literature in order to establish its neuroscientific foundations, and then advances a perceptual standpoint stemming from art and art history. Drawing from feminist theories of embodiment, I reposition neuroaesthetics to incorporate art historical inquiries into body and mind through direct engagement with art. I argue that such a revised neuroaesthic perception must take into account post-humanist troublings of nature/culture dichotomies. I also suggest that the paradigm for embodied perception that has emerged from both cognitive neuroscience and affect theory can expand neuroaesthetic understanding. My investigation has led me to first-hand experience as a research subject of neuroscience experiments, which show that current fMRI contexts in fact delimit the perception of art and inhibit possible neuroaesthetic significance. Instead, I undertake neuroaesthetic research in exhibition contexts where self-reflexive awareness facilitates insights into perception and cognition that are inaccessible within the epistemological conditions of neuroscience labs. The first case study examines how an installation by the FASTWÜRMS collective reveals cognitive processes of abduction by inviting navigation through an infinitely complex web of objects and images. Turning from association to visual cognition, I consider how Olafur Eliasson’s immersive light installations manipulate colour perception thereby facilitating critical awareness of techno-mediated environments. Third, my analysis of a conceptual work by Kristin Lucas explores how the performance of digital and legal technology invites embodied transformations. Finally, I examine how the affective tensions produced in a video by Omer Fast activate an awareness of intersubjective communication that corresponds with recent neuroscientific developments in mirror-neuron theory. By taking contemporary artworks as its focus, the dissertation extends neuroaesthetic inquiry to demonstrate contextual understandings of how the cognitive processes of art constitute physiological engagements between body, brain and world

An experimental and clinical investigation of psychological and neural factors associated with individual differences in pain and pain modulation

Chronic pain is a multi-faceted condition comprising of pathological, psychological and biological influences. This poses a significant problem to accurate assessment and treatment, with symptomology commonly not matching pathology. It is also unclear why some individuals develop chronic pain, while others appear resilient. Identifying individual differences in pain processing and modulation may be one method to help identify individuals who are susceptible to pain. Consequently, this thesis examined pain, its assessment and management in a clinical setting and individual differences in pain response in a laboratory setting. Study one evaluated pain ratings from hysteroscopy patients, to understand the prevalence of pain. Clinician estimates of pain were used to examine the accuracy of clinical pain assessment and how this related to pain management. Despite being considered a minimally-painful procedure, we found that patients’ pain ratings varied substantially, and were inversely correlated with clinician estimates. Our results indicate that hysteroscopy should not be advertised as a minimally-painful procedure. Advancing pre-surgical assessments to predict individuals at risk of developing pain could have important clinical implications. Individual differences in pain behaviour and response were examined in studies two and three, using resting-state connectivity in healthy controls. Study 2 investigated dispositional mindfulness, alongside sensory and cognitive pain variables. Trait mindfulness was associated with beneficial pain responses. Mindfulness was also associated with higher functional connectivity to the somatosensory cortex, and lower connectivity to the prefrontal cortex, with a precuneus seed. Our results may suggest that trait mindfulness is associated with increased sensory, present-moment focus, facilitating more effective pain management. Study 3 investigated Conditioned Pain Modulation (CPM), which quantifies the efficiency of descending modulation circuitry. Our results indicate that high CPM is associated with increased connectivity between pain modulatory and processing regions. Taken together, this research suggests that clinical assessments may benefit from psychometrics quantifying individual differences in their intrinsic ability to manage pain, to detect patients vulnerable to pain

Examining Resting-state Functional and Structural Connectivity of the Attention Networks after Early Brain Insults

Brain insults that occur early in life often lead to cognitive impairments, and sustained attention is highly vulnerable to the initial event as well as to the altered structural and functional brain development that follows. Sustained attention impairments are associated with neural changes in specific brain networks – default mode network (DMN) and central executive network (CEN) – that are crucial for proper attention functioning in healthy populations. Prior studies have, however, typically focused on adult cohorts, which is not applicable to understanding structural and functional changes in the developing brain. There are relatively few studies that have examined these networks in children with an early life injury with advanced quantitative neuroimaging techniques (structural magnetic resonance imaging (MRI) and functional MRI). Thus, the current thesis used these methods to investigate DMN and CEN changes following an early life brain insult in children with traumatic brain injury (TBI), epilepsy, or heterogeneous brain insults with the aim to identify shared neural changes in heterogeneous patient cohorts that underpin common attention impairments. The current thesis has reported reduced functional connectivity in the DMN regions (posterior cingulate cortex and medial prefrontal cortex) in children with TBI, and in the left parietal lobe in children with focal epilepsy as compared to controls at 2-years post-injury. Children with epilepsy however showed no differences in the structural covariance network when compared to controls. Children with heterogeneous brain insults also showed no significant functional and structural connectivity changes when imaging data were acquired in the acute post-insult period. This thesis is however limited by the lack of behavioural measures, and future studies should integrate neuropsychology and neuroimaging to better understand the relationships between the brain connectivity changes and attention deficits, therefore allowing the identification of children who would benefit most from early interventions that could improve their long-term neurocognitive outcomes

Understanding mechanisms related to psychosis in Motor Neurone Disease

Psychosis is a challenging feature of the syndromes of motor neurone disease (MND), frontotemporal dementia (FTD) and their overlap (FTD-MND). Clinically evident psychosis is not common, except in those with C9orf72+ expansions. However, subthreshold psychosis or pre-psychosis processes are common and provide the opportunity to study the mechanisms of psychosis in MND and FTD-MND. My aim was to identify the prevalence and the cognitive and neural correlates of psychosis, and related processes, in MND. I used a tiered cohort study approach. Tier 1 introduced screening as standard in a regional MND clinic (N=111) using the Edinburgh Cognitive and Behavioural ALS Screen and Cambridge Behavioural Inventory-Revised (CBI-R). In Tier 2, 60 patients and 30 controls underwent neuropsychological assessment, including (i) evidence-based decision-making, to quantify jumping to conclusions (JTC), (ii) attentional control and associative learning, (iii) perceptual inference, and (iv) psychiatric screening with Neuropsychiatric Inventory (NPI), Brief Psychiatric Rating Scale (BRPS), and the Comprehensive Assessment of At-Risk Mental States (CAARMS). Tier 3 included magnetic resonance imaging of 30 patients and 20 controls. Carer reports in Tier 1 indicated that 10% of patients exhibited features suggestive of psychosis and 40% exhibited behavioural change. In Tier 2, many patients manifested abnormal behaviours (CBI-R 41%; NPI showed 19%; BPRS 24%), with 12-16% showing psychosis-specific symptoms (CBI-R and NPI psychosis index scores). In the jumping to conclusions task, patients made decisions based on less evidence than controls and were insensitive to negative feedback. Carer ratings of patient behaviour correlated with performance on the jumping to conclusions task when decisions were rewarded or costs fixed. Attentional shifting and perceptual inference were normal in MND. A principal component analysis (PCA) of questionnaires revealed two component scores, reflecting distinct patients’ and carers’ perspectives. The imaging analyses focused on the correlates of jumping to conclusions and insensitivity to negative feedback, as a potential risk profile for psychosis, with exploratory analyses of the correlates of the CBI-R psychosis index, and carers’ ratings of behaviour from the PCA. Using a Freesurfer regions-of-interest approach, grey matter volume correlated inversely with CBI-R psychosis index in the caudate, amygdala, cingulate and hippocampus. Using tract-based spatial statistics, increased mean diffusivity (MD) of diffusion weighted imaging correlated with the CBI-R psychosis responses in inferior longitudinal and uncinate fasciculi. Cost sensitivity in the JTC task correlated with cingulate and cerebellar grey matter volumes. White matter correlates of cost sensitivity included reduced FA with increasing cost sensitivity in white matter connecting the inferior frontal lobe in controls and patients. Although overt psychosis is uncommon in MND, many patients displayed abnormal behaviour or cognitive symptoms, including suboptimal reasoning biases and inferential impulsivity. Degeneration of cerebellar, cingulate and striatal grey matter, and adjacent major white matter tracts, may underlie these cognitive impairments and together represent a vulnerability to develop psychosis. Compromised reasoning and inference have implications for clinical management, including decisions around treatment options and management of well-being in MND.This research was funded by Alzheimer’s Research UK Studentship (PhD2017-26); Medical Research Council (SUAG 051/ G101400); and the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care