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MRI theory and use

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https://www.readbyqxmd.com/read/28226699/estimating-multimodal-brain-connectivity-in-multiple-sclerosis-an-exploratory-factor-analysis
#1
Matteo Mancini, Giovanni Giulietti, Barbara Spano, Marco Bozzali, Mara Cercignani, Silvia Conforto, Matteo Mancini, Giovanni Giulietti, Barbara Spano, Marco Bozzali, Mara Cercignani, Silvia Conforto, Giovanni Giulietti, Mara Cercignani, Silvia Conforto, Matteo Mancini, Barbara Spano, Marco Bozzali
Graph-theoretical approaches have become a popular way to model brain data collected using magnetic resonance imaging (MRI), both from the structural and the functional perspectives. In structural networks, tract-based mapping allows to model different aspects of brain structures by means of the specific characteristics of the different MRI modalities. However, there has been little effort to join the information carried by each modality and to understand what level of common variance is shown in these data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28219628/subcortical-brain-volume-differences-in-participants-with-attention-deficit-hyperactivity-disorder-in-children-and-adults-a-cross-sectional-mega-analysis
#2
Martine Hoogman, Janita Bralten, Derrek P Hibar, Maarten Mennes, Marcel P Zwiers, Lizanne S J Schweren, Kimm J E van Hulzen, Sarah E Medland, Elena Shumskaya, Neda Jahanshad, Patrick de Zeeuw, Eszter Szekely, Gustavo Sudre, Thomas Wolfers, Alberdingk M H Onnink, Janneke T Dammers, Jeanette C Mostert, Yolanda Vives-Gilabert, Gregor Kohls, Eileen Oberwelland, Jochen Seitz, Martin Schulte-Rüther, Sara Ambrosino, Alysa E Doyle, Marie F Høvik, Margaretha Dramsdahl, Leanne Tamm, Theo G M van Erp, Anders Dale, Andrew Schork, Annette Conzelmann, Kathrin Zierhut, Ramona Baur, Hazel McCarthy, Yuliya N Yoncheva, Ana Cubillo, Kaylita Chantiluke, Mitul A Mehta, Yannis Paloyelis, Sarah Hohmann, Sarah Baumeister, Ivanei Bramati, Paulo Mattos, Fernanda Tovar-Moll, Pamela Douglas, Tobias Banaschewski, Daniel Brandeis, Jonna Kuntsi, Philip Asherson, Katya Rubia, Clare Kelly, Adriana Di Martino, Michael P Milham, Francisco X Castellanos, Thomas Frodl, Mariam Zentis, Klaus-Peter Lesch, Andreas Reif, Paul Pauli, Terry L Jernigan, Jan Haavik, Kerstin J Plessen, Astri J Lundervold, Kenneth Hugdahl, Larry J Seidman, Joseph Biederman, Nanda Rommelse, Dirk J Heslenfeld, Catharina A Hartman, Pieter J Hoekstra, Jaap Oosterlaan, Georg von Polier, Kerstin Konrad, Oscar Vilarroya, Josep Antoni Ramos-Quiroga, Joan Carles Soliva, Sarah Durston, Jan K Buitelaar, Stephen V Faraone, Philip Shaw, Paul M Thompson, Barbara Franke
BACKGROUND: Neuroimaging studies have shown structural alterations in several brain regions in children and adults with attention deficit hyperactivity disorder (ADHD). Through the formation of the international ENIGMA ADHD Working Group, we aimed to address weaknesses of previous imaging studies and meta-analyses, namely inadequate sample size and methodological heterogeneity. We aimed to investigate whether there are structural differences in children and adults with ADHD compared with those without this diagnosis...
February 16, 2017: Lancet Psychiatry
https://www.readbyqxmd.com/read/28213111/childhood-maltreatment-is-associated-with-alteration-in-global-network-fiber-tract-architecture-independent-of-history-of-depression-and-anxiety
#3
Kyoko Ohashi, Carl M Anderson, Elizabeth A Bolger, Alaptagin Khan, Cynthia E McGreenery, Martin H Teicher
Childhood maltreatment is a major risk factor for psychopathology. It is also associated with alterations in the network architecture of the brain, which we hypothesized may play a significant role in the development of psychopathology. In this study, we analyzed the global network architecture of physically healthy unmedicated 18-25 year old subjects (n=262) using diffusion tensor imaging (DTI) MRI and tractography. Anatomical networks were constructed from fiber streams interconnecting 90 cortical or subcortical regions for subjects with no-to-low (n=122) versus moderate-to-high (n=140) exposure to maltreatment...
February 16, 2017: NeuroImage
https://www.readbyqxmd.com/read/28181217/hypercoagulability-and-migraine
#4
Gretchen E Tietjen, Stuart A Collins
BACKGROUND: A growing body of literature suggests that migraineurs, particularly those with aura, have an increased risk for ischemic stroke, but not via enhanced atherosclerosis. The theory that micro-emboli induced ischemia provokes cortical spreading depression (ie, symptomatic aura) in migraineurs but transient ischemic attacks in others highlights a potential role for hypercoagulability as a link between migraine (with aura) and stroke. AIM: Our objective is to summarize the literature evaluating the association of migraine with various acquired or inheritable thrombophilic states, including those related to elevated estrogen levels, endothelial activation and dysfunction, antiphospholipid antibodies (aPL), deficiency of coagulation inhibitors, and presence of certain genetic polymorphisms...
February 9, 2017: Headache
https://www.readbyqxmd.com/read/28174333/resting-state-network-topology-differentiates-task-signals-across-the-adult-lifespan
#5
Micaela Y Chan, Fahd H Alhazmi, Denise C Park, Neil K Savalia, Gagan S Wig
: Brain network connectivity differs across individuals. For example, older adults exhibit less segregated resting-state sub-networks relative to younger adults (e.g., Chan et al., 2014). It has been hypothesized that individual differences in network connectivity impact the recruitment of brain areas during task execution. While recent studies have described the spatial overlap between resting-state functional correlation (RSFC) sub-networks and task-evoked activity, it is unclear whether individual variations in the connectivity pattern of a brain area (topology) relates to its activity during task execution...
February 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28171781/increased-white-matter-radial-diffusivity-is-associated-with-prefrontal-cortical-folding-deficits-in-schizophrenia
#6
C Christoph Schultz, Gerd Wagner, Claudia Schachtzabel, Jürgen R Reichenbach, Ralf G M Schlösser, Heinrich Sauer, Kathrin Koch
The neuronal underpinnings of cortical folding alterations in schizophrenia remain unclear. Theories on the physiological development of cortical folds stress the importance of white matter fibers for this process and disturbances of fiber tracts might be relevant for cortical folding alterations in schizophrenia. Nine-teen patients with schizophrenia and 19 healthy subjects underwent T1-weighted MRI and DTI. Cortical folding was computed using a surface based approach. DTI was analyzed using FSL and SPM 5...
February 4, 2017: Psychiatry Research
https://www.readbyqxmd.com/read/28149924/deformable-image-registration-for-tissues-with-large-displacements
#7
Xishi Huang, Jing Ren, Anwar Abdalbari, Mark Green
Image registration for internal organs and soft tissues is considered extremely challenging due to organ shifts and tissue deformation caused by patients' movements such as respiration and repositioning. In our previous work, we proposed a fast registration method for deformable tissues with small rotations. We extend our method to deformable registration of soft tissues with large displacements. We analyzed the deformation field of the liver by decomposing the deformation into shift, rotation, and pure deformation components and concluded that in many clinical cases, the liver deformation contains large rotations and small deformations...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28129150/the-spurs-algorithm-for-resampling-an-irregularly-sampled-signal-onto-a-cartesian-grid
#8
Amir Kiperwas, Daniel Rosenfeld, Yonina C Eldar
We present an algorithm for resampling a function from its values on a non-Cartesian grid onto a Cartesian grid. This problem arises in many applications such as MRI, CT, radio astronomy and geophysics. Our algorithm, termed SParse Uniform ReSampling (SPURS), employs methods from modern sampling theory to achieve a small approximation error while maintaining low computational cost. The given non-Cartesian samples are projected onto a selected intermediate subspace, spanned by integer translations of a compactly supported kernel function...
November 1, 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28127519/increased-thalamic-centrality-and-putamen-thalamic-connectivity-in-patients-with-parkinsonian-resting-tremor
#9
Quanquan Gu, Hengyi Cao, Min Xuan, Wei Luo, Xiaojun Guan, Jingjing Xu, Peiyu Huang, Minming Zhang, Xiaojun Xu
INTRODUCTION: Evidence has indicated a strong association between hyperactivity in the cerebello-thalamo-motor cortical loop and resting tremor in Parkinson's disease (PD). Within this loop, the thalamus serves as a central hub based on its structural centrality in the generation of resting tremor. To study whether this thalamic abnormality leads to an alteration at the whole-brain level, our study investigated the role of the thalamus in patients with parkinsonian resting tremor in a large-scale brain network context...
January 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28116232/changes-in-functional-organization-and-white-matter-integrity-in-the-connectome-in-parkinson-s-disease
#10
Sule Tinaz, Peter M Lauro, Pritha Ghosh, Codrin Lungu, Silvina G Horovitz
Parkinson's disease (PD) leads to dysfunction in multiple cortico-striatal circuits. The neurodegeneration has also been associated with impaired white matter integrity. This structural and functional "disconnection" in PD needs further characterization. We investigated the structural and functional organization of the PD whole brain connectome consisting of 200 nodes using diffusion tensor imaging and resting-state functional MRI, respectively. Data from 20 non-demented PD patients on dopaminergic medication and 20 matched controls were analyzed using graph theory-based methods...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28113840/a-projection-algorithm-for-gradient-waveforms-design-in-magnetic-resonance-imaging
#11
Nicolas Chauffert, Pierre Weiss, Jonas Kahn, Philippe Ciuciu
Collecting the maximal amount of information in a given scanning time is a major concern in Magnetic Resonance Imaging (MRI) to speed up image acquisition. The hardware constraints (gradient magnitude, slew rate, ...), physical distortions (e.g., off-resonance effects) and sampling theorems (Shannon, compressed sensing) must be taken into account simultaneously, which makes this problem extremely challenging. To date, the main approach to design gradient waveform has consisted of selecting an initial shape (e...
March 21, 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28112222/color-coded-visualization-of-magnetic-resonance-imaging-multiparametric-maps
#12
Jakob Nikolas Kather, Anja Weidner, Ulrike Attenberger, Yannick Bukschat, Cleo-Aron Weis, Meike Weis, Lothar R Schad, Frank Gerrit Zöllner
Multiparametric magnetic resonance imaging (mpMRI) data are emergingly used in the clinic e.g. for the diagnosis of prostate cancer. In contrast to conventional MR imaging data, multiparametric data typically include functional measurements such as diffusion and perfusion imaging sequences. Conventionally, these measurements are visualized with a one-dimensional color scale, allowing only for one-dimensional information to be encoded. Yet, human perception places visual information in a three-dimensional color space...
January 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28093049/efficient-variational-approach-to-multimodal-registration-of%C3%A2-anatomical%C3%A2-and%C3%A2-functional-intra-patient-tumorous-brain-data
#13
Alvar-Ginés Legaz-Aparicio, Rafael Verdú-Monedero, Jorge Larrey-Ruiz, Juan Morales-Sánchez, Fernando López-Mir, Valery Naranjo, Ángela Bernabéu
This paper addresses the functional localization of intra-patient images of the brain. Functional images of the brain (fMRI and PET) provide information about brain function and metabolism whereas anatomical images (MRI and CT) supply the localization of structures with high spatial resolution. The goal is to find the geometric correspondence between functional and anatomical images in order to complement and fuse the information provided by each imaging modality. The proposed approach is based on a variational formulation of the image registration problem in the frequency domain...
November 29, 2016: International Journal of Neural Systems
https://www.readbyqxmd.com/read/28090589/spiral-perfusion-imaging-with-consecutive-echoes-spice%C3%A2-for-the-simultaneous-mapping-of-dsc-and-dce-mri-parameters-in-brain-tumor-patients-theory-and-initial-feasibility
#14
Eric S Paulson, Douglas E Prah, Kathleen M Schmainda
Dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) are the perfusion imaging techniques most frequently used to probe the angiogenic character of brain neoplasms. With these methods, T1- and T2/T2*-weighted imaging sequences are used to image the distribution of gadolinium (Gd)-based contrast agents. However, it is well known that Gd exhibits combined T1, T2, and T2* shortening effects in tissue, and therefore, the results of both DCE- and DSC-MRI can be confounded by these opposing effects...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28066844/tight-graph-framelets-for-sparse-diffusion-mri-q-space-representation
#15
Pew-Thian Yap, Bin Dong, Yong Zhang, Dinggang Shen
In diffusion MRI, the outcome of estimation problems can often be improved by taking into account the correlation of diffusion-weighted images scanned with neighboring wavevectors in q-space. For this purpose, we propose in this paper to employ tight wavelet frames constructed on non-flat domains for multi-scale sparse representation of diffusion signals. This representation is well suited for signals sampled regularly or irregularly, such as on a grid or on multiple shells, in q-space. Using spectral graph theory, the frames are constructed based on quasi-affine systems (i...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28061002/closed-form-expressions-for-flip-angle-variation-that-maximize-total-signal-in-t1-weighted-rapid-gradient-echo-mri
#16
Matthias Drobnitzky, Uwe Klose
PURPOSE: Magnetization-prepared rapid gradient-echo (MPRAGE) sequences are commonly employed for T1-weighted structural brain imaging. Following a contrast preparation radiofrequency (RF) pulse the data acquisition proceeds under non-equilibrium conditions of the relaxing longitudinal magnetization. Variation of the flip angle can be used to maximize total available signal. Simulated annealing or greedy algorithms have so far been published to numerically solve this problem, with signal to noise ratios optimized for clinical imaging scenarios by adhering to a predefined shape of the signal evolution...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28053037/left-anterior-temporal-lobe-and-bilateral-anterior-cingulate-cortex-are-semantic-hub-regions-evidence-from-behavior-nodal-degree-mapping-in-brain-damaged-patients
#17
Ying Zhao, Luping Song, Junhua Ding, Nan Lin, Qiang Wang, Xiaoxia Du, Rong Sun, Zaizhu Han
: The organizational principles of semantic memory in the human brain are still controversial. Although studies have shown that the semantic system contains hub regions that bind information from different sensorimotoric modalities to form concepts, it is unknown whether there are hub regions other than the anterior temporal lobe (ATL). Meanwhile, previous studies have rarely used network measurements to explore the hubs or correlated network indexes with semantic performance, although the most direct supportive evidence of hubs should come from the network perspective...
January 4, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28040909/mri-surface-coil-pair-with-strong-inductive-coupling
#18
Richard R Mett, Jason W Sidabras, James S Hyde
A novel inductively coupled coil pair was used to obtain magnetic resonance phantom images. Rationale for using such a structure is described in R. R. Mett et al. [Rev. Sci. Instrum. 87, 084703 (2016)]. The original rationale was to increase the Q-value of a small diameter surface coil in order to achieve dominant loading by the sample. A significant improvement in the vector reception field (VRF) is also seen. The coil assembly consists of a 3-turn 10 mm tall meta-metallic self-resonant spiral (SRS) of inner diameter 10...
December 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28033566/towards-a-holistic-cortical-thickness-descriptor-heat-kernel-based-grey-matter-morphology-signatures
#19
Gang Wang, Yalin Wang
In this paper, we propose a heat kernel based regional shape descriptor that may be capable of better exploiting volumetric morphological information than other available methods, thereby improving statistical power on brain magnetic resonance imaging (MRI) analysis. The mechanism of our analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral meshes. In order to capture profound brain grey matter shape changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between white-grey matter and CSF-grey matter boundary surfaces by computing the streamlines in a tetrahedral mesh...
February 15, 2017: NeuroImage
https://www.readbyqxmd.com/read/28018208/global-efficiency-of-structural-networks-mediates-cognitive-control-in-mild-cognitive-impairment
#20
Rok Berlot, Claudia Metzler-Baddeley, M Arfan Ikram, Derek K Jones, Michael J O'Sullivan
Background: Cognitive control has been linked to both the microstructure of individual tracts and the structure of whole-brain networks, but their relative contributions in health and disease remain unclear. Objective: To determine the contribution of both localized white matter tract damage and disruption of global network architecture to cognitive control, in older age and Mild Cognitive Impairment (MCI). Materials and Methods: Twenty-five patients with MCI and 20 age, sex, and intelligence-matched healthy volunteers were investigated with 3 Tesla structural magnetic resonance imaging (MRI)...
2016: Frontiers in Aging Neuroscience
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