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https://www.readbyqxmd.com/read/29148120/mapping-brown-adipose-tissue-based-on-fat-water-fraction-provided-by-z-spectral-imaging
#1
Alessandro Scotti, Rong-Wen Tain, Weiguo Li, Victoria Gil, Chong Wee Liew, Kejia Cai
BACKGROUND: Brown adipose tissue (BAT) has a great relevance in metabolic diseases and has been shown to be reduced in obesity and insulin resistance patients. Currently, Dixon MRI is used to calculate fat-water fraction (FWF) and differentiate BAT from white adipose tissue (WAT). However, it may fail in areas of phase wrapping and introduce fat-water swapping artifacts. PURPOSE: To investigate the capacity of the Z-spectrum imaging (ZSI) for the identification of BAT in vivo...
November 17, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29126001/a-robust-heteronuclear-dipolar-recoupling-method-comparable-to-tedor-for-proteins-in-magic-angle-spinning-solid-state-nmr
#2
Zhengfeng Zhang, Jianping Li, Yanke Chen, Huayong Xie, Jun Yang
In this letter, we propose a robust heteronuclear dipolar recoupling method for proteins in magic-angle spinning (MAS) solid-state NMR. This method is as simple, robust and efficient as the well-known TEDOR in the aspect of magnetization transfer between (15)N and (13)C. Deriving from our recent band-selective dual back-to-back pulses (DBP) (Zhang et al., 2016), this method uses new phase-cycling schemes to realize broadband DBP (Bro-DBP). For broadband (15)N-(13)C magnetization transfer (simultaneous (15)N→(13)C' and (15)N→(13)Cα), Bro-DBP has almost the same (15)N→(13)Cα efficiency while offers 30-40% enhancement on (15)N→(13)C' transfer, compared to TEDOR...
October 31, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29119933/pharmacological-and-non-pharmacological-therapies-of-cognitive-impairment-in-multiple-sclerosis
#3
Elzbieta Miller, Agnieszka Morel, Justyna Redlicka, Igor Miller, Joanna Saluk
Cognitive impairment is one of the most important clinical features of neurodegenerative disorders including multiple sclerosis (MS). Conducted research shows that up to 65 percent of MS patients have cognitive deficits such as episodic memory, sustained attention, reduced verbal fluency; however, the cognitive MS domain is information processing speed. It is the first syndrome of cognitive dysfunction and the most widely affected in MS. Occasionally these impairments occur even before the appearance of physical symptoms...
November 9, 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/29116557/bidirectional-band-selective-magnetization-transfer-along-the-protein-backbone-doubles-the-information-content-of-solid-state-nmr-correlation-experiments
#4
M M Jolly, J A Jarvis, M Carravetta, M H Levitt, P T F Williamson
Resonance assignment is the first stage towards solving the structure of a protein. This is normally achieved by the employment of separate inter and intra residue experiments. By utilising the mixed rotation and rotary recoupling (MIRROR) condition it is possible to double the information content through the efficient bidirectional transfer of magnetization from the CO to its adjacent Cα and the Cα of the subsequent amino acid. We have incorporated this into a 3D experiment, a 3D-MIRROR-NCOCA, where correlations present in the 3D spectrum permit the sequential assignment of the protein backbone from a single experiment as we have demonstrated on a microcrystalline preparation of GB3...
November 8, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/29096052/toppe-a-framework-for-rapid-prototyping-of-mr-pulse-sequences
#5
Jon-Fredrik Nielsen, Douglas C Noll
PURPOSE: To introduce a framework for rapid prototyping of MR pulse sequences. METHODS: We propose a simple file format, called "TOPPE", for specifying all details of an MR imaging experiment, such as gradient and radiofrequency waveforms and the complete scan loop. In addition, we provide a TOPPE file "interpreter" for GE scanners, which is a binary executable that loads TOPPE files and executes the sequence on the scanner. We also provide MATLAB scripts for reading and writing TOPPE files and previewing the sequence prior to hardware execution...
November 2, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29091341/four-in-vivo-g-ratio-weighted-imaging-methods-comparability-and-repeatability-at-the-group-level
#6
Isabel Ellerbrock, Siawoosh Mohammadi
A recent method, denoted in vivo g-ratio-weighted imaging, has related the microscopic g-ratio, only accessible by ex vivo histology, to noninvasive MRI markers for the fiber volume fraction (FVF) and myelin volume fraction (MVF). Different MRI markers have been proposed for g-ratio weighted imaging, leaving open the question which combination of imaging markers is optimal. To address this question, the repeatability and comparability of four g-ratio methods based on different combinations of, respectively, two imaging markers for FVF (tract-fiber density, TFD, and neurite orientation dispersion and density imaging, NODDI) and two imaging markers for MVF (magnetization transfer saturation rate, MT, and, from proton density maps, macromolecular tissue volume, MTV) were tested in a scan-rescan experiment in two groups...
November 1, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29089830/qualitative-and-quantitative-comparison-of-contrast-enhanced-fluid-attenuated-inversion-recovery-magnetization-transfer-spin-echo-and-fat-saturation-t1-weighted-sequences-in-infectious-meningitis
#7
Rajiv Azad, Mohit Tayal, Sheenam Azad, Garima Sharma, Rajendra Kumar Srivastava
OBJECTIVE: To compare the contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR), the CE T1-weighted (CE-T1W) sequence with fat suppression (FS) and magnetization transfer (MT) for early detection and characterization of infectious meningitis. MATERIALS AND METHODS: Fifty patients and 10 control subjects were evaluated with the CE-FLAIR and the CE-T1W sequences with FS and MT. Qualitative assessment was done by two observers for presence and grading of abnormal leptomeningeal enhancement...
November 2017: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
https://www.readbyqxmd.com/read/29082667/advances-in-non-invasive-myelin-imaging
#8
REVIEW
Florence Heath, Samuel A Hurley, Heidi Johansen-Berg, Cassandra Sampaio-Baptista
Myelin is important for the normal development and healthy function of the nervous system. Recent developments in MRI acquisition and tissue modelling aim to provide a better characterization and more specific markers for myelin. This allows for specific monitoring of myelination longitudinally and non-invasively in the healthy brain as well as assessment of treatment and intervention efficacy. Here we offer a non-technical review of MRI techniques developed to specifically monitor myelin such as magnetization transfer (MT) and myelin water imaging (MWI)...
October 30, 2017: Developmental Neurobiology
https://www.readbyqxmd.com/read/29080236/shuffled-magnetization-prepared-multicontrast-rapid-gradient-echo-imaging
#9
Peng Cao, Xucheng Zhu, Shuyu Tang, Andrew Leynes, Angela Jakary, Peder E Z Larson
PURPOSE: To develop a novel acquisition and reconstruction method for magnetization-prepared 3-dimensional multicontrast rapid gradient-echo imaging, using Hankel matrix completion in combination with compressed sensing and parallel imaging. METHODS: A random k-space shuffling strategy was implemented in simulation and in vivo human experiments at 7 T for 3-dimensional inversion recovery, T2 /diffusion preparation, and magnetization transfer imaging. We combined compressed sensing, based on total variation and spatial-temporal low-rank regularizations, and parallel imaging with pixel-wise Hankel matrix completion, allowing the reconstruction of tens of multicontrast 3-dimensional images from 3- or 6-min scans...
October 27, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29076591/long-term-magnetization-transfer-ratio-evolution-in-multiple-sclerosis-white-matter-lesions
#10
Yufan Zheng, Jar-Chi Lee, Richard Rudick, Elizabeth Fisher
BACKGROUND AND PURPOSE: Magnetization transfer ratio (MTR), a magnetic resonance imaging technique used to assess tissue integrity, correlates with demyelination and axonal loss in multiple sclerosis (MS) lesions. In acute white matter lesions, short-term MTR changes mainly reflect demyelination and remyelination, in addition to edema and axonal and glial changes. Long-term MTR changes in MS lesions have not been studied extensively. METHODS: A new quantitative image analysis method was developed to measure long-term MTR changes in MS lesions...
October 27, 2017: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
https://www.readbyqxmd.com/read/29068880/quantitative-magnetization-transfer-mri-measurements-of-the-anterior-spinal-cord-region-are-associated-with-clinical-outcomes-in-cervical-spondylotic-myelopathy
#11
Michael Brendan Cloney, Zachary A Smith, Kenneth A Weber, Todd B Parrish
STUDY DESIGN: case-control. OBJECTIVE: To understand the role of magnetization transfer ratio in identifying patients with clinically significant myelopathy and disability. SUMMARY OF BACKGROUND DATA: Magnetization transfer ratio (MTR) is a quantitative measure that correlates with myelin loss and neural tissue destruction in a variety of neurological diseases. However, the usefulness of MTR in patients with cervical spondylotic myelopathy (CSM) has not been examined...
October 24, 2017: Spine
https://www.readbyqxmd.com/read/29066395/associations-between-prenatal-childhood-and-adolescent-stress-and-variations-in-white-matter-properties-in-young-men
#12
REVIEW
Sarah K G Jensen, Melissa Pangelinan, Lassi Björnholm, Anja Klasnja, Alexander Leemans, Mark Drakesmith, C J Evans, Edward D Barker, Tomáš Paus
OBJECTIVE: Previous studies have shown that both pre- and post-natal adversities, the latter including exposures to stress during childhood and adolescence, explain variation in structural properties of white matter (WM) in the brain. While previous studies have examined effects of independent stress exposures within one developmental period, such as childhood, we examine effects of stress across development using data from a prospective longitudinal study. More specifically, we ask how stressful events during prenatal development, childhood, and adolescence relate to variation in WM properties in early adulthood in young men recruited from a birth cohort...
October 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/29064775/uspio-positive-ms-lesions-are-associated-with-greater-tissue-damage-than-gadolinium-positive-only-lesions-during-3-year-follow-up
#13
Anne Kerbrat, Benoit Combès, Olivier Commowick, Adil Maarouf, Elise Bannier, Jean Christophe Ferré, Ayman Tourbah, Jean-Philippe Ranjeva, Christian Barillot, Gilles Edan
BACKGROUND: Identifying in vivo the processes that determine lesion severity in multiple sclerosis (MS) remains a challenge. OBJECTIVES: To describe the dynamics of ultrasmall superparamagnetic iron oxide (USPIO) enhancement in MS lesions and the relationship between USPIO enhancement and microstructural changes over 3 years. METHODS: Lesion development was assessed at baseline, Months 3, 6, and 9, using magnetic resonance imaging (MRI) with gadolinium and USPIO...
October 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/29059929/assessment-of-chemoradiotherapy-response-in-glioma-with-magnetic-resonance-amide-proton-transfer-imaging-in-a-rodent-model
#14
Jing Zhao, Yinsheng Chen, Yiying Zhao, Shasha Yang, Zhongping Chen, Yin Wu
Magnetic resonance amide proton transfer (APT) imaging has proved its potential for detecting tumors and evaluating treatment response by depicting chemical exchange saturation transfer effect between the endogenous protein/peptide amide proton and bulk water. However, conventional asymmetry analysis for APT effect measurement is susceptible to concomitant contributions, particular semisolid magnetic transfer (MT) and nuclear overhauser effect. In this study, dominant saturation transfer (ST) effects, including direct water saturation and MT, were estimated from a sum of two Lorentzian functions...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29053775/neuroinflammation-and-its-relationship-to-changes-in-brain-volume-and-white-matter-lesions-in-multiple-sclerosis
#15
Gourab Datta, Alessandro Colasanti, Eugenii A Rabiner, Roger N Gunn, Omar Malik, Olga Ciccarelli, Richard Nicholas, Eline Van Vlierberghe, Wim Van Hecke, Graham Searle, Andre Santos-Ribeiro, Paul M Matthews
Brain magnetic resonance imaging is an important tool in the diagnosis and monitoring of multiple sclerosis patients. However, magnetic resonance imaging alone provides limited information for predicting an individual patient's disability progression. In part, this is because magnetic resonance imaging lacks sensitivity and specificity for detecting chronic diffuse and multi-focal inflammation mediated by activated microglia/macrophages. The aim of this study was to test for an association between 18 kDa translocator protein brain positron emission tomography signal, which arises largely from microglial activation, and measures of subsequent disease progression in multiple sclerosis patients...
November 1, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29044691/the-role-of-magnetization-transfer-in-the-observed-contrast-in-t1-weighted-imaging-under-clinical-setups
#16
U Eliav, G Navon
In T1 weighted magnetic resonance imaging of brain and spinal cord in the clinical setting, the white matter (WM) appears with greater intensity than the gray matter (GM). This contrast has been assigned to differences in T1 values. In these experiments the RF pulses are too long to excite both the water and the species with restricted motion of the protons (SRMP). In in vitro studies using short RF pulses, the contrast is reversed, with greater intensity for the GM. These results raise the question of whether magnetization transfer (MT) plays a role in the contrast observed in the T1 weighting experiments...
October 18, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/29043804/proton-assisted-recoupling-par-in-peptides-and-proteins
#17
Kevin J Donovan, Sheetal K Jain, Robert Silvers, Sara Linse, Robert G Griffin
Proton assisted recoupling (PAR) is examined by exploring optimal experimental conditions and magnetization transfer rates in a variety of biologically relevant nuclear spin-systems including simple amino acids, model peptides and two proteins - nanocrystalline protein G (GB1), and importantly amyloid beta 1-42 (M0Aβ1-42) fibrils. A selective PAR protocol, SUBPAR (Setting Up Better Proton Assisted Recoupling), is described to observe magnetization transfer in one-dimensional spectra, which minimizes experiment time (in comparison to 2D experiments) and thereby enables an efficient assessment of optimal PAR conditions for a desired magnetization transfer...
October 18, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29041865/imaging-outcome-measures-for-progressive-multiple-sclerosis-trials
#18
Marcello Moccia, Nicola de Stefano, Frederik Barkhof
Imaging markers that are reliable, reproducible and sensitive to neurodegenerative changes in progressive multiple sclerosis (MS) can enhance the development of new medications with a neuroprotective mode-of-action. Accordingly, in recent years, a considerable number of imaging biomarkers have been included in phase 2 and 3 clinical trials in primary and secondary progressive MS. Brain lesion count and volume are markers of inflammation and demyelination and are important outcomes even in progressive MS trials...
October 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/29030880/direct-saturation-corrected-chemical-exchange-saturation-transfer-mri-of-glioma-simplified-decoupling-of-amide-proton-transfer-and-nuclear-overhauser-effect-contrasts
#19
Iris Yuwen Zhou, Enfeng Wang, Jerry S Cheung, Dongshuang Lu, Yang Ji, Xiaoan Zhang, Giulia Fulci, Phillip Zhe Sun
PURPOSE: Chemical exchange saturation transfer (CEST) MRI has shown promise in tissue characterization in diseases like stroke and tumor. However, in vivo CEST imaging such as amide proton transfer (APT) MRI is challenging because of concomitant factors such as direct water saturation, macromolecular magnetization transfer, and nuclear overhauser effect (NOE), which lead to a complex contrast in the commonly used asymmetry analysis (MTRasym). Here, we propose a direct saturation-corrected CEST (DISC-CEST) analysis for simplified decoupling and quantification of in vivo CEST effects...
October 13, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29021778/the-combined-quantification-and-interpretation-of-multiple-quantitative-magnetic-resonance-imaging-metrics-enlightens-longitudinal-changes-compatible-with-brain-repair-in-relapsing-remitting-multiple-sclerosis-patients
#20
Guillaume Bonnier, Benedicte Maréchal, Mário João Fartaria, Pavel Falkowskiy, José P Marques, Samanta Simioni, Myriam Schluep, Renaud Du Pasquier, Jean-Philippe Thiran, Gunnar Krueger, Cristina Granziera
OBJECTIVE: Quantitative and semi-quantitative MRI (qMRI) metrics provide complementary specificity and differential sensitivity to pathological brain changes compatible with brain inflammation, degeneration, and repair. Moreover, advanced magnetic resonance imaging (MRI) metrics with overlapping elements amplify the true tissue-related information and limit measurement noise. In this work, we combined multiple advanced MRI parameters to assess focal and diffuse brain changes over 2 years in a group of early-stage relapsing-remitting MS patients...
2017: Frontiers in Neurology
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