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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
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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...
December 26, 2016: NeuroImage
https://www.readbyqxmd.com/read/28018208/global-efficiency-of-structural-networks-mediates-cognitive-control-in-mild-cognitive-impairment
#8
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
https://www.readbyqxmd.com/read/28006727/the-relationship-between-mri-quantitative-parameters-and-the-expression-of-hypoxia-inducible-factor-1-alpha-in-cerebral-astrocytoma
#9
Chang Shu, Jinhuan Wang
OBJECTIVE: Astrocytoma is the common type of glioma. But the MRI scanning for astrocytoma preoperation pathological diagnosis is not exact. The purpose of this study was to use the MRI multi quantitative parameters to improve the diagnosis of astrocytoma and exploit their molecular mechanism related to the expression of HIF-1α. METHODS: Superconducting MR scanner and its work station were used to calculate the MRI multi quantitative parameters of the selected patients in this experiment...
November 23, 2016: Clinical Neurology and Neurosurgery
https://www.readbyqxmd.com/read/28004791/free-triiodothyronine-level-correlates-with-myocardial-injury-and-prognosis-in-idiopathic-dilated-cardiomyopathy-evidence-from-cardiac-mri-and-spect-pet-imaging
#10
Wenyao Wang, Haixia Guan, Wei Fang, Kuo Zhang, A Martin Gerdes, Giorgio Iervasi, Yi-Da Tang
Thyroid dysfunction is associated with poor prognosis in heart failure, but theories of mechanisms are mainly based on animal experiments, not on human level. We aimed to explore the relation between thyroid function and myocardial injuries in idiopathic dilated cardiomyopathy (IDCM) using cardiac magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET). Myocardial fibrosis was detected by late gadolinium enhancement (LGE) MRI, and myocardial perfusion/metabolism was evaluated by (99m)Tc-MIBI SPECT /(18)F-FDG PET imaging...
December 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27990134/allocentric-spatial-memory-testing-predicts-conversion-from-mild-cognitive-impairment-to-dementia-an-initial-proof-of-concept-study
#11
Ruth A Wood, Kuven K Moodley, Colin Lever, Ludovico Minati, Dennis Chan
The hippocampus is one of the first regions to exhibit neurodegeneration in Alzheimer's disease (AD), and knowledge of its role in allocentric spatial memory may therefore aid early diagnosis of AD. The 4 Mountains Test (4MT) is a short and easily administered test of spatial memory based on the cognitive map theory of hippocampal function as derived from rodent single cell and behavioral studies. The 4MT has been shown in previous cross-sectional studies to be sensitive and specific for mild cognitive impairment (MCI) due to AD...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/27989847/assessing-and-tuning-brain-decoders-cross-validation-caveats-and-guidelines
#12
Gaël Varoquaux, Pradeep Reddy Raamana, Denis A Engemann, Andrés Hoyos-Idrobo, Yannick Schwartz, Bertrand Thirion
Decoding, i.e. prediction from brain images or signals, calls for empirical evaluation of its predictive power. Such evaluation is achieved via cross-validation, a method also used to tune decoders' hyper-parameters. This paper is a review on cross-validation procedures for decoding in neuroimaging. It includes a didactic overview of the relevant theoretical considerations. Practical aspects are highlighted with an extensive empirical study of the common decoders in within- and across-subject predictions, on multiple datasets -anatomical and functional MRI and MEG- and simulations...
January 15, 2017: NeuroImage
https://www.readbyqxmd.com/read/27984540/electrophysiological-dynamic-brain-connectivity-during-symbolic-magnitude-comparison-in-children-with-different-mathematics-achievement-levels
#13
Fabiola R Gómez-Velázquez, Hugo Vélez-Pérez, Aurora Espinoza-Valdez, Rebeca Romo-Vazquez, Ricardo A Salido-Ruiz, Vanessa Ruiz-Stovel, Geisa B Gallardo-Moreno, Andrés A González-Garrido, Gustavo Berumen
Children with mathematical difficulties usually have an impaired ability to process symbolic representations. Functional MRI methods have suggested that early frontoparietal connectivity can predict mathematic achievements; however, the study of brain connectivity during numerical processing remains unexplored. With the aim of evaluating this in children with different math proficiencies, we selected a sample of 40 children divided into two groups [high achievement (HA) and low achievement (LA)] according to their arithmetic scores in the Wide Range Achievement Test, 4th ed...
December 15, 2016: Neuroreport
https://www.readbyqxmd.com/read/27943448/one-second-mri-of-a-three-dimensional-vocal-tract-to-measure-dynamic-articulator-modifications
#14
Michael Burdumy, Louisa Traser, Fabian Burk, Bernhard Richter, Matthias Echternach, Jan G Korvink, Jürgen Hennig, Maxim Zaitsev
PURPOSE: To enable three-dimensional (3D) vocal tract imaging of dynamic singing or speech tasks at voxel sizes of 1.6 × 1.6 × 1.3 mm(3) at 1.3 s per image. MATERIALS AND METHODS: A Stack-of-Stars method was implemented and enhanced to allow for fast and efficient k-space sampling of the box-shaped vocal tract using a 3 Tesla MRI system. Images were reconstructed using an off-line image reconstruction using compressed sensing theory, leading to the abovementioned spatial and temporal resolutions...
December 9, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27939369/hippocampal-structure-predicts-cortical-indices-of-reactivation-of-related-items
#15
John A Walker, Kathy A Low, Mark A Fletcher, Neal J Cohen, Gabriele Gratton, Monica Fabiani
One of the key components of relational memory is the ability to bind together the constituent elements of a memory experience, and this ability is thought to be supported by the hippocampus. Previously we had shown that these relational bindings can be used to reactivate the cortical processors of an absent item in the presence of a relationally bound associate (Walker et al., 2014). Specifically, we recorded the event-related optical signal (EROS) when presenting the scene of a face-scene pair during a preview period immediately preceding a test display, and demonstrated reactivation of a face-processing cortical area (the superior temporal sulcus, STS) for scenes that had been previously paired with faces, relative to scenes that had not...
December 7, 2016: Neuropsychologia
https://www.readbyqxmd.com/read/27937140/evaluation-of-whole-brain-resting-state-functional-connectivity-in-spinal-cord-injury-a-large-scale-network-analysis-using-network-based-statistic
#16
Mayank Kaushal, Akinwunmi Oni-Orisan, Gang Chen, Wenjun Li, Jack Leschke, B Douglas Ward, Benjamin T Kalinosky, Matthew D Budde, Brian D Schmit, Shi-Jiang Li, Vaishnavi Muqeet, Shekar N Kurpad
Large-scale network analysis characterizes the brain as a complex network of nodes and edges to evaluate functional connectivity patterns. The utility of graph-based techniques has been demonstrated in an increasing number of resting-state functional MRI (rs-fMRI) studies in the normal and diseased brain. However, to our knowledge, graph theory has not been used to study the reorganization pattern of resting-state brain networks in patients with traumatic complete spinal cord injury (SCI). In the present analysis, we applied a graph-theoretical approach to explore changes to global brain network architecture as a result of SCI...
December 9, 2016: Journal of Neurotrauma
https://www.readbyqxmd.com/read/27930915/anatomical-dysconnectivity-in-bipolar-disorder-compared-with-schizophrenia-a-selective-review-of-structural-network-analyses-using-diffusion-mri
#17
REVIEW
Stefani O'Donoghue, Laurena Holleran, Dara M Cannon, Colm McDonald
BACKGROUND: The dysconnectivity hypothesis suggests that psychotic illnesses arise not from regionally specific focal pathophysiology, but rather from impaired neuroanatomical integration across networks of brain regions. Decreased white matter organization has been hypothesized to be a feature of psychotic illnesses in general, which is supported by meta-analyses of DTI studies in bipolar disorder and schizophrenia. Although many diffusion MRI studies investigate bipolar disorder and schizophrenia alone, relatively few studies directly compare structural features in these psychotic illnesses...
February 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/27920792/hippocampal-volumetry-as-a-biomarker-for-dementia-in-people-with-low-education
#18
Jaime D Mondragón, César Celada-Borja, Fernando Barinagarrementeria-Aldatz, Martín Burgos-Jaramillo, Héctor Manuel Barragán-Campos
BACKGROUND/AIMS: To evaluate the relationship between hippocampal volume and cognitive decline in patients with dementia due to probable Alzheimer's disease (AD), amnestic mild cognitive impairment (aMCI) and education, and the possible relationship between cognitive reserve and education in this population. METHODS: From February 2013 to October 2015, 76 patients (25 men, 51 women) were classified according to the NIA-AA diagnostic criteria. We used two 3.0-tesla MRI scanners and performed manual hippocampal volumetry...
September 2016: Dementia and Geriatric Cognitive Disorders Extra
https://www.readbyqxmd.com/read/27919546/brain-morphometry-predicts-individual-creative-potential-and-the-ability-to-combine-remote-ideas
#19
David Bendetowicz, Marika Urbanski, Clarisse Aichelburg, Richard Levy, Emmanuelle Volle
For complex mental functions such as creative thinking, inter-individual variability is useful to better understand the underlying cognitive components and brain anatomy. Associative theories propose that creative individuals have flexible semantic associations, which allows remote elements to be formed into new combinations. However, the structural brain variability associated with the ability to combine remote associates has not been explored. To address this question, we performed a voxel-based morphometry (VBM) study and explored the anatomical connectivity of significant regions...
November 15, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/27918896/the-physical-mechanism-of-inhomogeneous-magnetization-transfer-mri
#20
Alan P Manning, Kimberley L Chang, Alex L MacKay, Carl A Michal
Inhomogeneous MT (ihMT) is a new magnetic resonance imaging technique that shows promise for myelin selectivity. Materials with a high proportion of lipids, such as white matter tissue, show a reduced intensity in magnetic resonance images acquired with selective prepulses at positive and negative offsets simultaneously compared to images with a single positive or negative offset prepulse of the same power. This effect was initially explained on the basis of hole-burning in inhomogeneously broadened lines of the lipid proton spin system...
January 2017: Journal of Magnetic Resonance
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