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MRI theory and use

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https://www.readbyqxmd.com/read/28944305/network-organization-is-globally-atypical-in-autism-a-graph-theory-study-of-intrinsic-functional-connectivity
#1
Christopher L Keown, Michael C Datko, Colleen P Chen, José Omar Maximo, Afrooz Jahedi, Ralph-Axel Müller
BACKGROUND: Despite abundant evidence of brain network anomalies in autism spectrum disorder (ASD), findings have varied from broad functional underconnectivity to broad overconnectivity. Rather than pursuing overly simplifying general hypotheses ('under' vs. 'over'), we tested the hypothesis of atypical network distribution in ASD (i.e., participation of unusual loci in distributed functional networks). METHODS: We used a selective high-quality data subset from the ABIDE datashare (including 111 ASD and 174 typically developing [TD] participants) and several graph theory metrics...
January 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
https://www.readbyqxmd.com/read/28932236/quantitative-evaluation-of-temporal-regularizers-in-compressed-sensing-dynamic-contrast-enhanced-mri-of-the-breast
#2
Dong Wang, Lori R Arlinghaus, Thomas E Yankeelov, Xiaoping Yang, David S Smith
PURPOSE: Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is used in cancer imaging to probe tumor vascular properties. Compressed sensing (CS) theory makes it possible to recover MR images from randomly undersampled k-space data using nonlinear recovery schemes. The purpose of this paper is to quantitatively evaluate common temporal sparsity-promoting regularizers for CS DCE-MRI of the breast. METHODS: We considered five ubiquitous temporal regularizers on 4...
2017: International Journal of Biomedical Imaging
https://www.readbyqxmd.com/read/28894164/investigating-the-relationship-between-cerebrospinal-fluid-and-magnetic-induction-phase-shift-in-rabbit-intracerebral-hematoma-expansion-monitoring-by-mri
#3
Mingsheng Chen, Qingguang Yan, Jian Sun, Gui Jin, Mingxin Qin
In a prior study of intracerebral hemorrhage monitoring using magnetic induction phase shift (MIPS), we found that MIPS signal changes occurred prior to those seen with intracranial pressure. However, the characteristic MIPS alert is not yet fully explained. Combining the brain physiology and MIPS theory, we propose that cerebrospinal fluid (CSF) may be the primary factor that leads to hematoma expansion being alerted by MIPS earlier than with intracranial pressure monitoring. This paper investigates the relationship between CSF and MIPS in monitoring of rabbit intracerebral hemorrhage models, which is based on the MIPS measurements data, the quantified data on CSF from medical images and the amount of injected blood in the rabbit intracerebral hemorrhage model...
September 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28869842/changes-in-intrinsic-local-connectivity-after-reading-intervention-in-children-with-autism
#4
Jose O Maximo, Donna L Murdaugh, Sarah O'Kelley, Rajesh K Kana
Most of the existing behavioral and cognitive intervention programs in autism spectrum disorders (ASD) have not been tested at the neurobiological level, thus falling short of finding quantifiable neurobiological changes underlying behavioral improvement. The current study takes a translational neuroimaging approach to test the impact of a structured visual imagery-based reading intervention on improving reading comprehension and assessing its underlying local neural circuitry. Behavioral and resting state functional MRI (rs-fMRI) data were collected from children with ASD who were randomly assigned to an Experimental group (ASD-EXP; n=14) and a Wait-list control group (ASD-WLC; n=14)...
September 1, 2017: Brain and Language
https://www.readbyqxmd.com/read/28869162/a-novel-method-for-t2-quantification-in-presence-of-b1-inhomogeneities
#5
David Milford, Martin Bendszus, Sabine Heiland
INTRODUCTION: T2 relaxometry as a quantitative MRI technique offers a more precise characterization of tissue, compared with qualitative T2 weighted imaging. The issue, however, is that in typically used T2 relaxometry sequences such as a multi-spin echo sequences, incorrect refocussing flip angles and B1 inhomogeneities cause inaccuracies in T2 determination. The work presented here within presents a new technique for modelling T2 decay curves and thereby correcting T2 times altered by inhomogeneities...
August 28, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28859565/neuroplasticity-and-the-brain-connectome-what-can-jean-talairach-s-reflections-bring-to-modern-psychosurgery
#6
Pierre Bourdillon, Caroline Apra, Marc Lévêque, Fabien Vinckier
Contrary to common psychosurgical practice in the 1950s, Dr. Jean Talairach had the intuition, based on clinical experience, that the brain connectome and neuroplasticity had a role to play in psychosurgery. Due to the remarkable progress of pharmacology at that time and to the technical limits of neurosurgery, these concepts were not put into practice. Currently, these concepts are being confirmed by modern techniques such as neuroimaging and computational neurosciences, and could pave the way for therapeutic innovation in psychiatry...
September 2017: Neurosurgical Focus
https://www.readbyqxmd.com/read/28855125/theory-of-mind-in-multiple-sclerosis-a-neuropsychological-and-mri-study
#7
Moussa A Chalah, Paul Kauv, Jean-Pascal Lefaucheur, Jérôme Hodel, Alain Créange, Samar S Ayache
OBJECTIVES: Social cognition stands among the most frequently affected yet the least studied cognitive domains in multiple sclerosis (MS). Theory of mind (ToM) is a social cognitive facet that implies the one's ability to predict others' mental states. The objective of this study was to assess the relationship between ToM and neuropsychological and neuroimaging data. METHODS: Thirty-eight consecutive MS patients completed the Reading the Mind in the Eyes test (RMET)...
August 29, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28839006/the-physiology-of-oral-whistling-a-combined-radiographic-and-mri-analysis
#8
Alba Miranda Azola, Jeffrey Palmer, Rachel Mulheren, Riccardo Hofer, Florian Fischmeister, W Tecumseh Fitch
The fluid mechanics of whistling involve the instability of an air jet, resultant vortex rings, and the interaction of these rings with rigid boundaries (2,4). Experimental models support the hypothesis that the sound in human whistling is generated by a Helmholtz resonator, suggesting that the oral cavity acts as a resonant chamber bounded by two orifices, posteriorly by raising the tongue to the hard palate, and anteriorly by pursed lips 2,2,3). However, the detailed anatomical changes in the vocal tract and their relation to the frequencies generated have not been described in the literature...
August 24, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28830765/a-theoretical-signal-processing-framework-for-linear-diffusion-mri-implications-for-parameter-estimation-and-experiment-design
#9
Divya Varadarajan, Justin P Haldar
The data measured in diffusion MRI can be modeled as the Fourier transform of the Ensemble Average Propagator (EAP), a probability distribution that summarizes the molecular diffusion behavior of the spins within each voxel. This Fourier relationship is potentially advantageous because of the extensive theory that has been developed to characterize the sampling requirements, accuracy, and stability of linear Fourier reconstruction methods. However, existing diffusion MRI data sampling and signal estimation methods have largely been developed and tuned without the benefit of such theory, instead relying on approximations, intuition, and extensive empirical evaluation...
August 19, 2017: NeuroImage
https://www.readbyqxmd.com/read/28818694/diffusion-time-dependence-of-microstructural-parameters-in-fixed-spinal-cord
#10
REVIEW
Sune Nørhøj Jespersen, Jonas Lynge Olesen, Brian Hansen, Noam Shemesh
Biophysical modelling of diffusion MRI is necessary to provide specific microstructural tissue properties. However, estimating model parameters from data with limited diffusion gradient strength, such as clinical scanners, has proven unreliable due to a shallow optimization landscape. On the other hand, estimation of diffusion kurtosis (DKI) parameters is more robust, and its parameters may be connected to microstructural parameters, given an appropriate biophysical model. However, it was previously shown that this procedure still does not provide sufficient information to uniquely determine all model parameters...
August 14, 2017: NeuroImage
https://www.readbyqxmd.com/read/28763447/braph-a-graph-theory-software-for-the-analysis-of-brain-connectivity
#11
Mite Mijalkov, Ehsan Kakaei, Joana B Pereira, Eric Westman, Giovanni Volpe
The brain is a large-scale complex network whose workings rely on the interaction between its various regions. In the past few years, the organization of the human brain network has been studied extensively using concepts from graph theory, where the brain is represented as a set of nodes connected by edges. This representation of the brain as a connectome can be used to assess important measures that reflect its topological architecture. We have developed a freeware MatLab-based software (BRAPH-BRain Analysis using graPH theory) for connectivity analysis of brain networks derived from structural magnetic resonance imaging (MRI), functional MRI (fMRI), positron emission tomography (PET) and electroencephalogram (EEG) data...
2017: PloS One
https://www.readbyqxmd.com/read/28751514/syringomyelia-fluid-dynamics-and-cord-motion-revealed-by-serendipitous-null-point-artifacts-during-cine-mri
#12
C M Honey, K W Martin, M K S Heran
Dynamic MR imaging was used to evaluate a cervical syrinx in an adolescent boy with an associated hindbrain herniation. Null artifacts were present on one of the sequences that allowed simultaneous high-resolution visualization of syrinx fluid motion and the anatomy of the syrinx walls. A brief review of the theories of syrinx formation and propagation is provided with a comment on why the Williams "slosh" theory of syrinx progression is supported by our unique imaging.
July 27, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28741694/reduced-parahippocampal-volume-and-psychosis-symptoms-in-alzheimer-s-disease
#13
Emma McLachlan, Jennifer Bousfield, Robert Howard, Suzanne Reeves
OBJECTIVE: Establishing structural imaging correlates of psychosis symptoms in Alzheimer's disease (AD) could localise pathology and target symptomatic treatment. This study investigated whether psychosis symptoms are associated with visuoperceptual or frontal networks, and whether regional brain volume differences could be linked with the paranoid (persecutory delusions) or misidentification (misidentification phenomena and/or hallucinations) subtypes. METHODS: A total of 104 patients with probable AD (AddNeuroMed; 47 psychotic, 57 non-psychotic), followed up for at least one year with structural MRI at baseline...
July 25, 2017: International Journal of Geriatric Psychiatry
https://www.readbyqxmd.com/read/28730720/microstructural-white-matter-brain-abnormalities-in-patients-with-idiopathic-fecal-incontinence
#14
J Muthulingam, S Haas, T M Hansen, S Laurberg, L Lundby, H S Jørgensen, A M Drewes, K Krogh, J B Frøkjaer
BACKGROUND: Abnormal central nervous system processing of visceral sensation may be a part of the pathogenesis behind idiopathic fecal incontinence (IFI). Our aim was to characterize brain differences in patients with IFI and healthy controls by means of structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). METHODS: In 21 female patients with IFI and 15 female healthy controls, whole-brain structural differences in gray matter volume (GMV), cortical thickness, and white matter tracts fractional anisotropy (FA) were quantified...
July 21, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/28723344/social-cognition-impairments-after-aneurysmal-subarachnoid-haemorrhage-associations-with-deficits-in-interpersonal-behaviour-apathy-and-impaired-self-awareness
#15
Anne M Buunk, Jacoba M Spikman, Wencke S Veenstra, Peter Jan van Laar, Jan D M Metzemaekers, J Marc C van Dijk, Linda C Meiners, Rob J M Groen
Behavioural disturbances are frequently found after aneurysmal subarachnoid haemorrhage (aSAH). Social cognition impairments have been suggested as a possible underlying mechanism for behavioural problems. Also, aSAH is likely to result in damage affecting frontal-subcortical circuits underlying social cognition. Therefore, we aimed to investigate social cognition after aSAH and its associations with behavioural problems (deficits in interpersonal behaviour, apathy, and impaired self-awareness) and focal as well as diffuse brain damage...
July 16, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28708033/neuropsychological-profile-and-social-cognition-in-congenital-central-hypoventilation-syndrome-cchs-correlation-with-neuroimaging-in-a-clinical-case
#16
Borja Esteso Orduña, Raquel Seijas Gómez, Elena García Esparza, Emily M Briceño, Javier Melero Llorente, María de la Concepción Fournier Del Castillo
INTRODUCTION: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder due to paired-like homeobox gene (PHOX2B) mutations. CCHS patients suffer from dysregulation of the autonomic nervous system characterized by the absence of or extremely reduced response to hypercapnia and hypoxia, with neuropsychological deficits. The aim of this exploratory study is to describe the longitudinal neuropsychological profile and its correlations with magnetic resonance imaging (MRI) of a child with CCHS with a PHOX2B mutation...
July 14, 2017: Journal of Clinical and Experimental Neuropsychology
https://www.readbyqxmd.com/read/28670402/disc-rehydration-after-dynamic-stabilization-a-report-of-59-cases
#17
Atilla Yilmaz, Salim Senturk, Mehdi Sasani, Tunc Oktenoglu, Onur Yaman, Hakan Yildirim, Tuncer Suzer, Ali Fahir Ozer
STUDY DESIGN: A retrospective study investigating decrease in the nucleus pulposus signal intensity or disc height on magnetic resonance imaging (MRI) and disc degeneration. PURPOSE: Although a degenerated disc cannot self-regenerate, distraction or stabilization may provide suitable conditions for rehydration and possible regeneration. This study aimed to evaluate clinical outcomes and disc regeneration via MRI in a series of patients with degenerative disc disease (DDD) who underwent lumbar stabilization with a dynamic stabilization system (DSS)...
June 2017: Asian Spine Journal
https://www.readbyqxmd.com/read/28648465/planum-temporale-asymmetry-in-people-who-stutter
#18
Patricia M Gough, Emily L Connally, Peter Howell, David Ward, Jennifer Chesters, Kate E Watkins
PURPOSE: Previous studies have reported that the planum temporale - a language-related structure that normally shows a leftward asymmetry - had reduced asymmetry in people who stutter (PWS) and reversed asymmetry in those with severe stuttering. These findings are consistent with the theory that altered language lateralization may be a cause or consequence of stuttering. Here, we re-examined these findings in a larger sample of PWS. METHODS: We evaluated planum temporale asymmetry in structural MRI scans obtained from 67 PWS and 63 age-matched controls using: 1) manual measurements of the surface area; 2) voxel-based morphometry to automatically calculate grey matter density...
June 16, 2017: Journal of Fluency Disorders
https://www.readbyqxmd.com/read/28630885/bayesian-framework-inspired-no-reference-region-of-interest-quality-measure-for-brain-mri-images
#19
Michael Osadebey, Marius Pedersen, Douglas Arnold, Katrina Wendel-Mitoraj
We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed...
April 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28630340/enhancing-t1-magnetic-resonance-imaging-contrast-with-internalized-gadolinium-iii-in-a-multilayer-nanoparticle
#20
Valeria S Marangoni, Oara Neumann, Luke Henderson, Caterina C Kaffes, Hui Zhang, Runmin Zhang, Sandra Bishnoi, Ciceron Ayala-Orozco, Valtencir Zucolotto, James A Bankson, Peter Nordlander, Naomi J Halas
Multifunctional nanoparticles for biomedical applications have shown extraordinary potential as contrast agents in various bioimaging modalities, near-IR photothermal therapy, and for light-triggered therapeutic release processes. Over the past several years, numerous studies have been performed to synthesize and enhance MRI contrast with nanoparticles. However, understanding the MRI enhancement mechanism in a multishell nanoparticle geometry, and controlling its properties, remains a challenge. To systematically examine MRI enhancement in a nanoparticle geometry, we have synthesized MRI-active Au nanomatryoshkas...
July 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
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