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https://www.readbyqxmd.com/read/29313159/improved-differentiation-of-low-grade-and-high-grade-gliomas-and-detection-of-tumor-proliferation-using-apt-contrast-fitted-from-z-spectrum
#1
Jiaxuan Zhang, Wenzhen Zhu, Rongwen Tain, Xiaohong Joe Zhou, Kejia Cai
PURPOSE: The purpose of the study is to demonstrate the value of quantitative amide proton transfer (APT) imaging for differentiating glioma grades and detecting tumor proliferation. PROCEDURES: This study included 32 subjects with 16 low-grade gliomas (LGG) and 16 high-grade gliomas (HGG) confirmed by histopathology. Chemical exchange saturation transfer (CEST) magnetic resonance imaging with APT weighting was performed on a 3 T scanner. After B0 correction, Z-spectra were fitted with Lorentzian functions corresponding to the upfield semi-solid magnetization transfer and nuclear overhauser enhancement (MT&NOE) effect, the direct saturation (DS) effect, and the downfield APT effect centered at around - 1...
January 8, 2018: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://www.readbyqxmd.com/read/29312876/assessing-tissue-metabolism-by-phosphorous-31-magnetic-resonance-spectroscopy-and-imaging-a-methodology-review
#2
REVIEW
Yuchi Liu, Yuning Gu, Xin Yu
Many human diseases are caused by an imbalance between energy production and demand. Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide the unique opportunity for in vivo assessment of several fundamental events in tissue metabolism without the use of ionizing radiation. Of particular interest, phosphate metabolites that are involved in ATP generation and utilization can be quantified noninvasively by phosphorous-31 (31P) MRS/MRI. Furthermore, 31P magnetization transfer (MT) techniques allow in vivo measurement of metabolic fluxes via creatine kinase (CK) and ATP synthase...
December 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/29305910/the-development-of-brain-white-matter-microstructure
#3
Catherine Lebel, Sean Deoni
Throughout infancy, childhood, and adolescence, our brains undergo remarkable changes. Processes including myelination and synaptogenesis occur rapidly across the first 2-3 years of life, and ongoing brain remodeling continues into young adulthood. Studies have sought to characterize the patterns of structural brain development, and early studies predominately relied upon gross anatomical measures of brain structure, morphology, and organization. MRI offers the ability to characterize and quantify a range of microstructural aspects of brain tissue that may be more closely related to fundamental neurodevelopmental processes...
January 3, 2018: NeuroImage
https://www.readbyqxmd.com/read/29296621/rivastigmine-decreases-brain-damage-in-hiv-patients-with-mild-cognitive-deficits
#4
Gaetano Perrotta, Guillaume Bonnier, Djalel-Eddine Meskaldji, David Romascano, Ruslan Aydarkhanov, Alessandro Daducci, Samanta Simioni, Matthias Cavassini, Melanie Metral, François Lazeyras, Reto Meuli, Gunnar Krueger, Renaud A Du Pasquier, Cristina Granziera
Rivastigmine has been shown to improve cognition in HIV+ patients with minor neurocognitive disorders; however, the mechanisms underlying such beneficial effect are currently unknown. To assess whether rivastigmine therapy is associated with decreased brain inflammation and damage, we performed T1/T2* relaxometry and magnetization transfer imaging in 17 aviremic HIV+ patients with minor neurocognitive disorders enrolled on a crossed over randomized rivastigmine trial. Rivastigmine therapy was associated with changes in MRI metrics indicating a decrease in brain water content (i...
December 2017: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/29288037/simulation-based-quantification-of-native-t1-and-t2-of-the-myocardium-using-a-modified-molli-scheme-and-the-importance-of-magnetization-transfer
#5
Christos G Xanthis, Sebastian Bidhult, Andreas Greiser, Kelvin Chow, Richard B Thompson, Håkan Arheden, Anthony H Aletras
Quantitative cardiovascular Magnetic Resonance Imaging techniques are gaining wide acceptance within the MR community due to their potential to diagnose non-localized disease, guide therapy and improve patient outcome. During the last decade, there has been an increasing interest for developing new techniques that allow for simultaneous quantification of both T1 and T2 maps of myocardium. Newer studies demonstrated that the incorporation of MRI simulations could yield similar results to conventional mapping techniques in the myocardium...
December 26, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29243295/extended-phase-graph-formalism-for-systems-with-magnetization-transfer-and-exchange
#6
Shaihan J Malik, Rui Pedro A G Teixeira, Joseph V Hajnal
PURPOSE: An extended phase graph framework (EPG-X) for modeling systems with exchange or magnetization transfer (MT) is proposed. THEORY: EPG-X models coupled two-compartment systems by describing each compartment with separate phase graphs that exchange during evolution periods. There are two variants: EPG-X(BM) for systems governed by the Bloch-McConnell equations, and EPG-X(MT) for the pulsed MT formalism. For the MT case, the "bound" protons have no transverse components, so their phase graph consists of only longitudinal states...
December 15, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29223871/intensity-ratio-to-improve-black-hole-assessment-in-multiple-sclerosis
#7
Gautam Adusumilli, Kathryn Trinkaus, Peng Sun, Samantha Lancia, Jeffrey D Viox, Jie Wen, Robert T Naismith, Anne H Cross
BACKGROUND: Improved imaging methods are critical to assess neurodegeneration and remyelination in multiple sclerosis. Chronic hypointensities observed on T1-weighted brain MRI, "persistent black holes," reflect severe focal tissue damage. Present measures consist of determining persistent black holes numbers and volumes, but do not quantitate severity of individual lesions. OBJECTIVE: Develop a method to differentiate black and gray holes and estimate the severity of individual multiple sclerosis lesions using standard magnetic resonance imaging...
December 2, 2017: Multiple Sclerosis and related Disorders
https://www.readbyqxmd.com/read/29222677/diagnostic-evaluation-of-magnetization-transfer-and-diffusion-kurtosis-imaging-for-prostate-cancer-detection-in-a-re-biopsy-population
#8
Tristan Barrett, Mary McLean, Andrew N Priest, Edward M Lawrence, Andrew J Patterson, Brendan C Koo, Ilse Patterson, Anne Y Warren, Andrew Doble, Vincent J Gnanapragasam, Christof Kastner, Ferdia A Gallagher
OBJECTIVE: To evaluate diffusion kurtosis imaging (DKI) and magnetisation transfer imaging (MTI) compared to standard MRI for prostate cancer assessment in a re-biopsy population. METHODS: Thirty-patients were imaged at 3 T including DKI (Kapp and Dapp) with b-values 150/450/800/1150/1500 s/mm2 and MTI performed with and without MT saturation. Patients underwent transperineal biopsy based on prospectively defined MRI targets. Receiver-operating characteristic (ROC) analyses assessed the parameters and Wilcoxon-signed ranked test assessed relationships between metrics...
December 8, 2017: European Radiology
https://www.readbyqxmd.com/read/29219218/rotator-cuff-tendon-assessment-using-magic-angle-insensitive-3d-ultrashort-echo-time-cones-magnetization-transfer-ute-cones-mt-imaging-and-modeling-with-histological-correlation
#9
Yanchun Zhu, Xin Cheng, Yajun Ma, Jonathan H Wong, Yaoqin Xie, Jiang Du, Eric Y Chang
BACKGROUND: Rotator cuff tendons (RCTs) are challenging to image due to the "magic angle effect" and their short T2 . PURPOSE: To assess the degree of magic angle sensitivity of human RCTs and to utilize a 3D ultrashort echo time Cones sequence with magnetization transfer preparation (UTE-Cones-MT) and two-pool quantitative MT modeling with histological correlation. We hypothesized that MT parameters would be less sensitive to the magic angle compared with conventional T2 measurements...
December 8, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29208570/modelling-and-interpretation-of-magnetization-transfer-imaging-in-the-brain
#10
John G Sled
Magnetization transfer contrast has yielded insight into brain tissue microstructure changes across the lifespan and in a range of disorders. This progress has been aided by the development of quantitative magnetization transfer imaging techniques able to extract intrinsic properties of the tissue that are independent of the specifics of the data acquisition. While the tissue properties extracted by these techniques do not map directly onto specific cellular structures or pathological processes, a growing body of work from animal models and histopathological correlations aids the in vivo interpretation of magnetization transfer properties of tissue...
December 2, 2017: NeuroImage
https://www.readbyqxmd.com/read/29208569/a-digital-3d-atlas-of-the-marmoset-brain-based-on-multi-modal-mri
#11
Cirong Liu, Frank Q Ye, Cecil Chern-Chyi Yen, John D Newman, Daniel Glen, David A Leopold, Afonso C Silva
The common marmoset (Callithrix jacchus) is a New-World monkey of growing interest in neuroscience. Magnetic resonance imaging (MRI) is an essential tool to unveil the anatomical and functional organization of the marmoset brain. To facilitate identification of regions of interest, it is desirable to register MR images to an atlas of the brain. However, currently available atlases of the marmoset brain are mainly based on 2D histological data, which are difficult to apply to 3D imaging techniques. Here, we constructed a 3D digital atlas based on high-resolution ex-vivo MRI images, including magnetization transfer ratio (a T1-like contrast), T2w images, and multi-shell diffusion MRI...
December 2, 2017: NeuroImage
https://www.readbyqxmd.com/read/29193448/increased-cest-specificity-for-amide-and-fast-exchanging-amine-protons-using-exchange-dependent-relaxation-rate
#12
Xiao-Yong Zhang, Feng Wang, Junzhong Xu, Daniel F Gochberg, John C Gore, Zhongliang Zu
Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast-exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi-solid non-specific magnetization transfer (MT), the influence of water relaxation times (T1w ) and nearby overlapping CEST signals...
November 29, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/29189927/solvent-saturation-transfer-to-proteins-sstp-for-structural-and-functional-characterization-of-proteins
#13
Pushpa Mishra, C Ashley Barnes, Madeleine Strickland, Nico Tjandra
Protein structure determination using NMR is dependent on experimentally acquired distance restraints. Often, however, an insufficient number of these restraints are available for determining a protein's correct fold, much less its detailed three-dimensional structure. In consideration of this problem, we propose a simple means to acquire supplemental structural restraints from protein surface accessibilities using solvent saturation transfer to proteins (SSTP), based on the principles of paramagnetic chemical-exchange saturation transfer...
November 30, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/29162523/specific-visualization-of-neuromelanin-iron-complex-and-ferric-iron-in-the-human-post-mortem-substantia-nigra-using-mr-relaxometry-at-7t
#14
Hansol Lee, Sun-Yong Baek, Se Young Chun, Jae-Hyeok Lee, HyungJoon Cho
Neuromelanin (NM) is an endogenous iron chelating molecule of pigmented neurons in the human substantia nigra (SN). Along with the increase in iron deposition, the reduction in NM-containing dopaminergic neurons and the variation of iron load on NM are generally considered to be important factors participating to pathogenesis of Parkinson's disease (PD). The aim of this study was to non-invasively delineate the spatial distributions of paramagnetic magnetic susceptibility perturbers, such as NM-iron complex and ferric iron in SN...
November 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/29159467/the-use-of-multiparametric-quantitative-magnetic-resonance-imaging-for-evaluating-visually-assigned-lesion-groups-in-patients-with-multiple-sclerosis
#15
Christian Thaler, Tobias D Faizy, Jan Sedlacik, Maxim Bester, Jan-Patrick Stellmann, Christoph Heesen, Jens Fiehler, Susanne Siemonsen
In multiple sclerosis (MS), inflammatory lesions present a broad spectrum of histopathologic processes. For a better discrimination, lesions are visually defined into different lesion groups according to their appearance on conventional magnetic resonance imaging (MRI). The aim of this study was to investigate the properties of different MS lesion groups using multiparametric quantitative MRI. 35 patients diagnosed with relapsing-remitting MS received 3 Tesla MRI including magnetization-prepared 2 rapid acquisition gradient echo, diffusion tensor imaging and magnetization transfer imaging...
November 20, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/29151460/-evaluation-of-absorbed-dose-by-mri-read-out
#16
Shuji Usui
Three dimensional dose distribution by gel dosimeters is often read out by an MRI scanner, which is readily available in most hospitals. Both the T1 and T2 relaxation rates are used to evaluate the absorbed dose. This paper will describe the principle of the imaging sequences (spin echo, multiple spin echo, and inversion recovery methods) to measure the relaxation rate and the factors to affect the precision (signal noise ratio, temperature during scanning, coil, imaging artefact). Additionally, the magnetization transfer method will be mentioned as an alternative for low-density foam gel dosimeters...
2017: Japanese Journal of Medical Physics
https://www.readbyqxmd.com/read/29148120/mapping-brown-adipose-tissue-based-on-fat-water-fraction-provided-by-z-spectral-imaging
#17
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
#18
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
#19
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
#20
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
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