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https://www.readbyqxmd.com/read/28065850/deep-grey-matter-iron-accumulation-in-alcohol-use-disorder
#1
Michal Juhás, Hongfu Sun, Matthew R G Brown, Marnie B MacKay, Karl F Mann, Wolfgang H Sommer, Alan H Wilman, Serdar M Dursun, Andrew J Greenshaw
PURPOSE: Evaluate brain iron accumulation in alcohol use disorder (AUD) patients compared to controls using quantitative susceptibility mapping (QSM). METHODS: QSM was performed retrospectively by using phase images from resting state functional magnetic resonance imaging (fMRI). 20 male AUD patients and 15 matched healthy controls were examined. Susceptibility values were manually traced in deep grey matter regions including caudate nucleus, combined putamen and globus pallidus, combined substantia nigra and red nucleus, dentate nucleus, and a reference white matter region in the internal capsule...
January 5, 2017: NeuroImage
https://www.readbyqxmd.com/read/28046752/su-f-i-24-feasibility-of-magnetic-susceptibility-to-relative-electron-density-conversion-method-for-radiation-therapy
#2
K Ito, N Kadoya, M Chiba, K Sato, T Nagasaka, K Yamanaka, S Dobashi, K Takeda, H Matsushita, K Jingu
PURPOSE: The aim of this study is to develop radiation treatment planning using magnetic susceptibility obtained from quantitative susceptibility mapping (QSM) via MR imaging. This study demonstrates the feasibility of a method for generating a substitute for a CT image from an MRI. METHODS: The head of a healthy volunteer was scanned using a CT scanner and a 3.0 T MRI scanner. The CT imaging was performed with a slice thickness of 2.5 mm at 80 and 120 kV (dual-energy scan)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046245/su-d-207a-04-use-of-gradient-echo-plural-contrast-imaging-gepci-in-mr-guided-radiation-therapy-a-feasibility-study-targeting-brain-treatment
#3
B Cai, J Wen, Y Rao, C Tsien, J Huang, O Green, S Mutic, D Yablonskiy, H Gach
PURPOSE: To implement the Gradient Echo Plural Contrast Imaging(GEPCI) technique in MRI-simulation for radiation therapy and assess the feasibility of using GEPCI images with advanced inhomogeneity correction in MRI-guided radiotherapy for brain treatment. METHODS: An optimized multigradient-echo GRE sequence (TR=50ms;TE1=4ms;delta_TE=4ms;flip angle=300,11 Echoes) was developed to generate both structural (T1w and T2*w) and functional MRIs (field and susceptibility maps) from a single acquisition...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27995062/magnetic-susceptibility-in-the-deep-layers-of-the-primary-motor-cortex-in-amyotrophic-lateral-sclerosis
#4
M Costagli, G Donatelli, L Biagi, E Caldarazzo Ienco, G Siciliano, M Tosetti, M Cosottini
Amyotrophic Lateral Sclerosis (ALS) is a progressive neurological disorder that entails degeneration of both upper and lower motor neurons. The primary motor cortex (M1) in patients with upper motor neuron (UMN) impairment is pronouncedly hypointense in Magnetic Resonance (MR) T2* contrast. In the present study, 3D gradient-recalled multi-echo sequences were used on a 7 Tesla MR system to acquire T2*-weighted images targeting M1 at high spatial resolution. MR raw data were used for Quantitative Susceptibility Mapping (QSM)...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27987234/deciphering-fungal-dimorphism-farnesol-s-unanswered-questions
#5
Kenneth W Nickerson, Audrey L Atkin
Candida albicans excretes E,E-farnesol as a virulence factor and quorum sensing molecule (QSM) that prevents the yeast to hyphal conversion. Polke et al (2016) identified eed1Δ/Δ as the first farnesol hypersensitive mutant of C. albicans. eed1Δ/Δ also excretes 10X more farnesol and while able to form hyphae, it cannot maintain hyphae. This mutant enables new research into unanswered questions, including the existence of potential farnesol receptors and transporters, regulation of farnesol synthesis, and relationships among farnesol, germ tube formation and hyphal maintenance...
December 17, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27986608/changes-in-brain-iron-concentration-after-exposure-to-high-altitude-hypoxia-measured-by-quantitative-susceptibility-mapping
#6
Lin Chen, Congbo Cai, Tianhe Yang, Jianzhong Lin, Shuhui Cai, Jiaxing Zhang, Zhong Chen
Hypoxia can induce physiological changes. This study aims to explore effects of high-altitude (HA) hypoxia on cerebral iron concentration. Twenty-nine healthy sea-level participants were tested shortly before and after approximately 4-week adaptation to the HA environment at fQinghai-Tibet Plateau (4200m), and were re-investigated after re-adaptation to the sea-level environment one year later. Iron concentration was quantified with quantitative susceptibility mapping (QSM), and the results were compared with transverse relaxation rate (R(*)2) measurements...
December 14, 2016: NeuroImage
https://www.readbyqxmd.com/read/27939794/studying-cyto-and-myeloarchitecture-of-the-human-cortex-at-ultra-high-field-with-quantitative-imaging-r1-r2-and-magnetic-susceptibility
#7
José P Marques, Diana Khabipova, Rolf Gruetter
In this manuscript, the use of quantitative imaging at ultra-high field is evaluated as a mean to study cyto and myelo-architecture of the cortex. The quantitative contrasts used are the longitudinal relaxation rate (R1), apparent transverse relaxation rate (R2(*)) and quantitative susceptibility mapping (QSM). The quantitative contrasts were computed using high resolution in-vivo (0.65mm isotropic) brain data acquired at 7T. The performance of the different quantitative approaches was evaluated by visualizing the contrast between known highly myelinated primary sensory cortex regions and the neighbouring cortex...
December 7, 2016: NeuroImage
https://www.readbyqxmd.com/read/27906525/the-clinical-utility-of-qsm-disease-diagnosis-medical-management-and-surgical-planning
#8
REVIEW
Sarah Eskreis-Winkler, Yan Zhang, Jingwei Zhang, Zhe Liu, Alexey Dimov, Ajay Gupta, Yi Wang
Quantitative susceptibility mapping (QSM) is an MR technique that depicts and quantifies magnetic susceptibility sources. Mapping iron, the dominant susceptibility source in the brain, has many important clinical applications. Herein, we review QSM applications in the diagnosis, medical management, and surgical treatment of disease. To assist in early disease diagnosis, QSM can identify elevated iron levels in the motor cortex of amyotrophic lateral sclerosis patients, in the substantia nigra of Parkinson's disease (PD) patients, in the globus pallidus, putamen, and caudate of Huntington's disease patients, and in the basal ganglia of Wilson's disease patients...
December 1, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27859983/imaging-of-nigrosome-1-in-substantia-nigra-at-3t-using-multiecho-susceptibility-map-weighted-imaging-smwi
#9
Yoonho Nam, Sung-Min Gho, Dong-Hyun Kim, Eung Yeop Kim, Jongho Lee
PURPOSE: To enhance the visibility of nigrosome 1 in substantia nigra, which has recently been suggested as an imaging biomarker for Parkinson's disease (PD) at 3T magnetic resonance imaging (MRI). MATERIALS AND METHODS: The substantia nigra structure was visualized at 3T MRI using multiecho susceptibility map-weighted imaging (SMWI) in 15 healthy volunteers and 6 patients with Parkinson's disease (PD). The visibility of nigrosome 1 was further enhanced by acquiring data in an oblique-coronal imaging plane at a high spatial resolution (0...
November 11, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27833539/validity-of-quinpirole-sensitization-rat-model-of-ocd-linking-evidence-from-animal-and-clinical-studies
#10
REVIEW
Ales Stuchlik, Dominika Radostová, Hana Hatalova, Karel Vales, Tereza Nekovarova, Jana Koprivova, Jan Svoboda, Jiri Horacek
Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder with 1-3% prevalence. OCD is characterized by recurrent thoughts (obsessions) and repetitive behaviors (compulsions). The pathophysiology of OCD remains unclear, stressing the importance of pre-clinical studies. The aim of this article is to critically review a proposed animal model of OCD that is characterized by the induction of compulsive checking and behavioral sensitization to the D2/D3 dopamine agonist quinpirole. Changes in this model have been reported at the level of brain structures, neurotransmitter systems and other neurophysiological aspects...
2016: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/27821737/quasimodo-mediates-daily-and-acute-light-effects-on-drosophila-clock-neuron-excitability
#11
Edgar Buhl, Adam Bradlaugh, Maite Ogueta, Ko-Fan Chen, Ralf Stanewsky, James J L Hodge
We have characterized a light-input pathway regulating Drosophila clock neuron excitability. The molecular clock drives rhythmic electrical excitability of clock neurons, and we show that the recently discovered light-input factor Quasimodo (Qsm) regulates this variation, presumably via an Na(+), K(+), Cl(-) cotransporter (NKCC) and the Shaw K(+) channel (dKV3.1). Because of light-dependent degradation of the clock protein Timeless (Tim), constant illumination (LL) leads to a breakdown of molecular and behavioral rhythms...
November 22, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27763692/accelerated-mapping-of-magnetic-susceptibility-using-3d-planes-on-a-paddlewheel-pop-epi-at-ultra-high-field-strength
#12
Daniel Stäb, Steffen Bollmann, Christian Langkammer, Kristian Bredies, Markus Barth
With the advent of ultra-high field MRI scanners in clinical research, susceptibility based MRI has recently gained increasing interest because of its potential to assess subtle tissue changes underlying neurological pathologies/disorders. Conventional, but rather slow, three-dimensional (3D) spoiled gradient-echo (GRE) sequences are typically employed to assess the susceptibility of tissue. 3D echo-planar imaging (EPI) represents a fast alternative but generally comes with echo-time restrictions, geometrical distortions and signal dropouts that can become severe at ultra-high fields...
October 20, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27748454/colocalization-of-cerebral-iron-with-amyloid-beta-in-mild-cognitive-impairment
#13
J M G van Bergen, X Li, J Hua, S J Schreiner, S C Steininger, F C Quevenco, M Wyss, A F Gietl, V Treyer, S E Leh, F Buck, R M Nitsch, K P Pruessmann, P C M van Zijl, C Hock, P G Unschuld
Quantitative Susceptibility Mapping (QSM) MRI at 7 Tesla and 11-Carbon Pittsburgh-Compound-B PET were used for investigating the relationship between brain iron and Amyloid beta (Aβ) plaque-load in a context of increased risk for Alzheimer's disease (AD), as reflected by the Apolipoprotein E ε4 (APOE-e4) allele and mild cognitive impairment (MCI) in elderly subjects. Carriers of APOE-e4 with normal cognition had higher cortical Aβ-plaque-load than non-carriers. In MCI an association between APOE-e4 and higher Aβ-plaque-load was observable both for cortical and subcortical brain-regions...
October 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27744181/rapid-reconstruction-of-quantitative-susceptibility-mapping-via-improved-%C3%A2-0-norm-approximation
#14
Congbo Cai, Xi Chen, Weijun Liu, Shuhui Cai, Delu Zeng, Xinghao Ding
Quantitative susceptibility mapping (QSM) reconstruction is a well-known ill-posed problem. Various regularization techniques have been proposed for solving this problem. In this paper, a rapid method is proposed that uses ℓ0 norm minimization in a gradient domain. Because ℓ0 minimization is an NP-hard problem, a special alternating optimization strategy is employed to simplify the reconstruction algorithm. The proposed algorithm uses only simple point-wise multiplications and thresholding operations, and significantly speeds up the calculation...
October 4, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/27717080/an-illustrated-comparison-of-processing-methods-for-phase-mri-and-qsm-removal-of-background-field-contributions-from-sources-outside-the-region-of-interest
#15
Ferdinand Schweser, Simon Daniel Robinson, Ludovic de Rochefort, Wei Li, Kristian Bredies
The elimination of so-called background fields is an essential step in phase MRI and quantitative susceptibility mapping (QSM). Background fields, which are caused by sources outside the region of interest (ROI), are often one to two orders of magnitude stronger than tissue-related field variations from within the ROI, hampering quantitative interpretation of field maps. This paper reviews the current literature on background elimination algorithms for QSM and provides insights into similarities and differences between the many algorithms proposed...
October 7, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27699883/susceptibility-underestimation-in-a-high-susceptibility-phantom-dependence-on-imaging-resolution-magnitude-contrast-and-other-parameters
#16
Dong Zhou, Junghun Cho, Jingwei Zhang, Pascal Spincemaille, Yi Wang
PURPOSE: We assessed the accuracy of quantitative susceptibility mapping in a gadolinium balloon phantom with a large range of susceptibility values and imaging resolutions at 1.5 and 3 Tesla (T). THEORY AND METHODS: The phantom contained sources with susceptibility values of 0.4, 0.8, 1.6, and 3.2 ppm and was imaged at isotropic resolutions of 0.7, 0.8, 1.2, and 1.8 mm. Numerical simulations were performed to match the experimental findings. Voxel sensitivity effects were used to explain the susceptibility underestimations...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27687150/structural-and-functional-quantitative-susceptibility-mapping-from-standard-fmri-studies
#17
H Sun, P Seres, A H Wilman
Standard functional MRI (fMRI), which includes resting-state or paradigm-driven designs, is widely used in studies of brain function, aging, and disease. These fMRI studies typically use two-dimensional gradient echo-planar imaging, which inherently contains phase data that enables quantitative susceptibility mapping (QSM). This work focuses on the dual value of QSM within fMRI studies, by providing both a localized analysis of functional changes in activated tissue, and iron-sensitive structural maps in deep grey matter (DGM)...
September 30, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27664936/quantitative-assessment-of-gadolinium-deposition-in-dentate-nucleus-using-quantitative-susceptibility-mapping
#18
Takuya Hinoda, Yasutaka Fushimi, Tomohisa Okada, Yoshiki Arakawa, Chunlei Liu, Akira Yamamoto, Tsutomu Okada, Kazumichi Yoshida, Susumu Miyamoto, Kaori Togashi
PURPOSE: Gadolinium deposition in dentate nucleus (DN) has been reported after serial administration of gadolinium-based contrast agents (GBCAs). Gadolinium complexes have paramagnetic properties; therefore, we evaluated susceptibility changes of gadolinium deposition in DN using quantitative susceptibility mapping (QSM) for patients after serial administration of GBCAs. MATERIALS AND METHODS: In all, 48 patients with brain tumors, who had had serial GBCA administrations (GBCA group), and 48 healthy volunteers without any history of GBCA administrations (non-GBCA group) were enrolled in this study...
September 24, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27623739/a-functional-link-between-hyphal-maintenance-and-quorum-sensing-in-candida-albicans
#19
Melanie Polke, Marcel Sprenger, Kirstin Scherlach, María Cristina Albán-Proaño, Ronny Martin, Christian Hertweck, Bernhard Hube, Ilse D Jacobsen
Morphogenesis in Candida albicans requires hyphal initiation and maintenance, and both processes are regulated by the fungal quorum sensing molecule (QSM) farnesol. We show that deletion of C. albicans EED1, which is crucial for hyphal extension and maintenance, led to a dramatically increased sensitivity to farnesol, and thus identified the first mutant hypersensitive to farnesol. Furthermore, farnesol decreased the transient filamentation of an eed1Δ strain without inducing cell death, indicating that two separate mechanisms mediate quorum sensing and cell lysis by farnesol...
September 14, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27619999/an-illustrated-comparison-of-processing-methods-for-mr-phase-imaging-and-qsm-combining-array-coil-signals-and-phase-unwrapping
#20
Simon Daniel Robinson, Kristian Bredies, Diana Khabipova, Barbara Dymerska, José P Marques, Ferdinand Schweser
Phase imaging benefits from strong susceptibility effects at very high field and the high signal-to-noise ratio (SNR) afforded by multi-channel coils. Combining the information from coils is not trivial, however, as the phase that originates in local field effects (the source of interesting contrast) is modified by the inhomogeneous sensitivity of each coil. This has historically been addressed by referencing individual coil sensitivities to that of a volume coil, but alternative approaches are required for ultra-high field systems in which no such coil is available...
September 13, 2016: NMR in Biomedicine
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