Neuroscience
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Network science provides powerful access to essential organizational principles of the human brain. It has been applied in combination with graph theory to characterize brain connectivity patterns. In multiple sclerosis (MS), analysis of the brain networks derived from either structural or functional imaging provides new insights into pathological processes within the gray and white matter. ⋯ We further provide an outline of functional and structural connectivity patterns observed in MS, spanning from disconnection and disruption on one hand to adaptation and compensation on the other. Moreover, we link network changes and their relation to clinical disability based on the current literature. Finally, we discuss the perspective of network science in MS for future research and postulate its role in the clinical framework.
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Multiple Sclerosis (MS) is a chronic neurological disease that represents a leading cause of disability in young adults and is characterized by inflammation and degeneration of both white matter (WM) and gray matter (GM). Defining the presence or absence of inflammation on individual basis is a key point in choosing the therapy and monitoring the treatment response. Magnetic resonance imaging (MRI) represents the most sensitive non-invasive tool to monitor inflammation in the clinical practice. ⋯ New imaging techniques have been developed to study diffuse inflammation taking place outside the focal plaques. The scope of this review is to examine the various neuroimaging techniques and those biophysical quantities that can be non-invasively detected to enlighten the different aspects of neuroinflammation. Some techniques are commonly used in the clinical practice, while others are used in the research field to better understand the pathophysiological mechanisms of the disease and the role of inflammation.
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Positron emission tomography (PET) provides spatially localized information about brain metabolism and function and innovative tracers have extended this potential to the study of neuroinflammation (NI), an important process in the pathophysiology of several neurological disorders. However, PET is limited by low spatial resolution. Conversely, Magnetic Resonance Imaging (MRI) affords high-resolution information about brain anatomy and metabolism which can complement PET-related information as well as aid in post-processing of PET data. ⋯ While, the clinical applicability and impact on diagnostic accuracy of PET/MRI in neurological disorders is still under investigation, the study of NI, a complex processes mediated by multiple metabolic pathways and hence likely characterized by different biomarkers, represents an opportunity to characterize the added value of joint MRI-PET techniques in a clinical context. This would in turn offer improved diagnostic and prognostic tools in several neurological disorders in which NI is a key mediator. This review aims at summarizing the current state as well as future potential of using hybrid PET/MRI for characterizing NI phenomena, both in terms of technical challenges and clinical relevance.
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The gut-brain axis communicates the brain with the gut microbiota, a bidirectional conduit that has received increasing attention in recent years thanks to its emerging role in brain development and function. Alterations in microbiota composition have been associated to neurological and psychiatric disorders, and several studies suggest that the immune system plays a fundamental role in the gut-brain interaction. ⋯ In this "Perspective" article, we discuss recent efforts to combine data on the gut microbiota with the features that can be obtained from the conversion of brain images into mineable data. The subsequent analysis of these data for diagnostic and prognostic purposes is an approach we call radiomicrobiomics and it holds tremendous potential to enhance our understanding of this fascinating connection.
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In multiple sclerosis (MS), it would be of clinical value to be able to track the progression of axonal pathology, especially before the manifestation of clinical disability. However, non-invasive evaluation of short-term longitudinal progression of white matter integrity is challenging. This study aims at assessing longitudinal changes in the restricted (i.e. intracellular) diffusion signal fraction (FR) in early-stage MS by using ultra-high gradient strength multi-shell diffusion magnetic resonance imaging. ⋯ Taken together, our data provide evidence for progressive microstructural damage in the NAWM of early MS cases detectable already at 1-year follow-up. Our study highlights the value of multi-shell diffusion imaging for sensitive tracking of disease evolution in MS before any clinical changes are observed. This article is part of a Special Issue entitled: SI: MRI and Neuroinflammation.