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https://www.readbyqxmd.com/read/28547862/mri-evaluation-of-regional-and-longitudinal-changes-in-z-spectra-of-injured-spinal-cord-of-monkeys
#1
Feng Wang, Zhongliang Zu, Ruiqi Wu, Tung-Lin Wu, John C Gore, Li Min Chen
PURPOSE: In principle, MR methods that exploit magnetization transfer (MT) may be used to quantify changes in the molecular composition of tissues after injury. The ability to track such changes in injured spinal cord may allow more precise assessment of the state of neural tissues. METHODS: Z-Spectra were obtained from the cervical spinal cord before and after a unilateral dorsal column lesion in monkeys at 9.4T. The amplitudes of chemical exchange saturation transfer (CEST) and nuclear Overhauser enhancement (NOE) effects from multiple proton pools, along with nonspecific semisolid MT effects from immobile macromolecules, were quantified using a five-peak Lorenzian fitting of each Z-spectrum...
May 25, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28543840/imaging-of-nuclear-overhauser-enhancement-at-7-and-3%C3%A2-t
#2
Yuanyu Shen, Gang Xiao, Zhiwei Shen, Xiaolei Zhang, Xiangyong Tang, Wei Hu, Zhiyan Zhang, Jitian Guan, Renhua Wu
Nuclear Overhauser enhancement (NOE) is a type of magnetization transfer using cross-relaxation. It originates from mobile macromolecules, which may have relevance to the evaluation of tumor features. We studied the value of NOE imaging at 7 and 3 T and suggest a utility for diagnosing human brain tumors. Two types of protein solution at different concentrations and pH values, and six normal Sprague Dawley (SD) rats, were used to detect NOE signal with a 7 T scanner. Then, six healthy volunteers and 11 patients with brain tumors (six gliomas and five meningiomas) were included at 3 T...
May 24, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28542095/magnetization-transfer-magnetic-resonance-imaging-noninvasively-detects-renal-fibrosis-in-swine-atherosclerotic-renal-artery-stenosis-at-3-0-t
#3
Kai Jiang, Christopher M Ferguson, John R Woollard, Xiangyang Zhu, Lilach O Lerman
OBJECTIVES: Renal fibrosis is a useful biomarker for diagnosis and evaluation of therapeutic interventions of renal diseases but often requires invasive testing. Magnetization transfer magnetic resonance imaging (MT-MRI), which evaluates the presence of macromolecules, offers a noninvasive tool to probe renal fibrosis in murine renal artery stenosis (RAS) at 16.4 T. In this study, we aimed to identify appropriate imaging parameters for collagen detection at 3.0 T MRI and to test the utility of MT-MRI in measuring renal fibrosis in a swine model of atherosclerotic RAS (ARAS)...
May 24, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28527566/abnormalities-in-high-energy-phosphate-metabolism-in-first-episode-bipolar-disorder-measured-using-31-p-magnetic-resonance-spectroscopy
#4
Fei Du, Cagri Yuksel, Virginie-Anne Chouinard, Polly Huynh, Kyle Ryan, Bruce M Cohen, Dost Öngür
BACKGROUND: Brain energy metabolism is critical for supporting synaptic function and information processing. A growing body of evidence suggests abnormalities in brain bioenergetics in psychiatric disorders, including both bipolar disorder (BD) and schizophrenia. (31)P magnetic resonance spectroscopy provides a noninvasive window into these processes in vivo. Using this approach, we previously showed that patients with BD show normal adenosine triphosphate (ATP) and phosphocreatine levels at rest but cannot maintain normal ATP levels in the visual cortex during times of high energy demand (photic stimulation)...
April 7, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/28526431/measurement-of-apt-using-a-combined-cert-arex-approach-with-varying-duty-cycles
#5
Zhongliang Zu, Hua Li, Junzhong Xu, Xiao-Yong Zhang, Moritz Zaiss, Ke Li, Mark D Does, John C Gore, Daniel F Gochberg
The goal is to develop an imaging method where contrast reflects amide-water magnetization exchange, with minimal signal contributions from other sources. Conventional chemical exchange saturation transfer (CEST) imaging of amides (often called amide proton transfer, or APT, and quantified by the metric MTRasym) is confounded by several factors unrelated to amides, such as aliphatic protons, water relaxation, and macromolecular magnetization transfer. In this work, we examined the effects of combining our previous chemical exchange rotation (CERT) approach with the non-linear AREX method while using different duty cycles (DC) for the label and reference scans...
May 17, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28522663/the-use-of-noncontrast-quantitative-mri-to-detect-gadolinium-enhancing-multiple-sclerosis-brain-lesions-a-systematic-review-and-meta-analysis
#6
A Gupta, K Al-Dasuqi, F Xia, G Askin, Y Zhao, D Delgado, Y Wang
BACKGROUND: Concerns have arisen about the long-term health effects of repeat gadolinium injections in patients with multiple sclerosis and the incomplete characterization of MS lesion pathophysiology that results from relying on enhancement characteristics alone. PURPOSE: Our aim was to perform a systematic review and meta-analysis analyzing whether noncontrast MR imaging biomarkers can distinguish enhancing and nonenhancing brain MS lesions. DATA SOURCES: Our sources were Ovid MEDLINE, Ovid Embase, and the Cochrane data base from inception to August 2016...
May 18, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28510013/nmr-magnetization-transfer-analysis-of-rapid-membrane-transport-in-human-erythrocytes
#7
REVIEW
Dmitry Shishmarev, Philip W Kuchel
Nuclear magnetic resonance (NMR) magnetization-transfer (MT) experiments provide a convenient tool for studying rapid sub-second membrane-transport processes in situ in metabolically active cells. These experiments are used with membrane-permeable substances when separate (resolved) NMR signals are observed from their populations inside and outside the cells. Here, we provide a description of the theory and practice of the most common NMR MT experiments that have been used to study membrane-transport processes in human erythrocytes (red blood cells; RBCs)...
December 2016: Biophysical Reviews
https://www.readbyqxmd.com/read/28482644/olfactory-impairment-in-parkinson-s-disease-studied-with-diffusion-tensor-and%C3%A2-magnetization-transfer-imaging
#8
Charalampos Georgiopoulos, Marcel Warntjes, Nil Dizdar, Helene Zachrisson, Maria Engström, Sven Haller, Elna-Marie Larsson
BACKGROUND: Olfactory impairment is an early manifestation of Parkinson's disease (PD). Diffusion Tensor Imaging (DTI) and Magnetization Transfer (MT) are two imaging techniques that allow noninvasive detection of microstructural changes in the cerebral white matter. OBJECTIVE: To assess white matter alterations associated with olfactory impairment in PD, using a binary imaging approach with DTI and MT. METHODS: 22 PD patients and 13 healthy controls were examined with DTI, MT and an odor discrimination test...
May 5, 2017: Journal of Parkinson's Disease
https://www.readbyqxmd.com/read/28477231/comparison-of-the-free-and-ligand-bound-imino-hydrogen-exchange-rates-for-the-cocaine-binding-aptamer
#9
Zachary R Churcher, Miguel A D Neves, Howard N Hunter, Philip E Johnson
Using NMR magnetization transfer experiments, the hydrogen exchange rate constants (k ex ) of the DNA imino protons in the cocaine-binding aptamer have been determined for the free, cocaine-bound, and quinine-bound states. The secondary structure of the cocaine-binding aptamer is composed of three stems built around a three-way junction. In the free aptamer the slowest exchanging imino protons are located in the middle of the stems. The highest k ex values were found for a nucleotide in the GAA loop of stem 3 and for nucleotides at the end of the stems that form the three-way junction structure and in the tandem GA mismatch...
May 5, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28474409/amide-proton-transfer-cest-of-the-cervical-spinal-cord-in-multiple-sclerosis-patients-at-3t
#10
Samantha By, Robert L Barry, Alex K Smith, Bailey D Lyttle, Bailey A Box, Francesca R Bagnato, Siddharama Pawate, Seth A Smith
PURPOSE: The ability to evaluate pathological changes in the spinal cord in multiple sclerosis (MS) is limited because T1 - and T2 -w MRI imaging are not sensitive to biochemical changes in vivo. Amide proton transfer (APT) chemical exchange saturation transfer (CEST) can indirectly detect amide protons associated with proteins and peptides, potentially providing more pathological specificity. Here, we implement APT CEST in the cervical spinal cord of healthy and MS cohorts at 3T. METHODS: APT CEST of the cervical spinal cord was obtained in a cohort of 10 controls and 10 MS patients using a novel respiratory correction methodology...
May 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28470838/quantitative-magnetization-transfer-ultrashort-echo-time-imaging-using-a-time-efficient-3d-multispoke-cones-sequence
#11
Ya-Jun Ma, Eric Y Chang, Michael Carl, Jiang Du
PURPOSE: To accelerate the quantitative ultrashort echo time imaging using a time-efficient 3D multispoke Cones sequence with magnetization transfer (3D UTE-Cones-MT) and signal modeling. THEORY AND METHODS: A 3D UTE-Cones-MT acquisition scheme with multispoke per MT preparation and a modified rectangular pulse (RP) approximation was developed for two-pool MT modeling of macromolecular and water components including their relative fractions, relaxation times and exchange rates...
May 3, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28460267/development-of-compact-cs-corrector-for-desktop-electron-microscope
#12
Wei-Yu Chang, Fu-Rong Chen
The desktop Electron Microscopes (desktop EMs) have been commercialized in the recent years, offering a spatial resolution around 1nm in scanning-transmission mode in a routine operation. For the purpose of further improvement in spatial resolution and signal / noise, one may need an aberration corrector with a compact form in order to fit into a desktop EM. In this paper, the permanent magnets with tunable coil are implemented as a transfer lens doublet to realize a compact hexapole corrector for a desktop EM...
April 15, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28458999/magnetization-transfer-imaging-identifies-basal-ganglia-abnormalities-in-adult-adhd-that-are-invisible-to-conventional-t1-weighted-voxel-based-morphometry
#13
Arjun Sethi, Edwin Evelyn-Rahr, Nicholas Dowell, Sanjay Jain, Valerie Voon, Hugo D Critchley, Neil A Harrison, Mara Cercignani
In childhood, Attention Deficit Hyperactivity Disorder (ADHD) is reliably associated with reduced volume of the striatum. In contrast, striatal abnormalities are infrequently detected in voxel-based morphometry (VBM) neuroimaging studies of adults with ADHD. This discrepancy has been suggested to reflect normalisation of striatal morphology with age and prolonged treatment of symptoms. If so, this would indicate that while striatal abnormalities are linked to symptom expression in childhood, they cannot explain the persistence of these symptoms in adulthood...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28455264/using-functional-and-molecular-mri-techniques-to-detect-neuroinflammation-and-neuroprotection-after-traumatic-brain-injury
#14
Wenzhu Wang, Hong Zhang, Doon-Hoon Lee, Jintao Yu, Tian Cheng, Michael Hong, Shanshan Jiang, Heng Fan, Xi Huang, Jinyuan Zhou, Jian Wang
This study was designed to investigate whether functional and molecular MRI techniques are sensitive biomarkers for assessment of neuroinflammation and drug efficacy after traumatic brain injury (TBI) in rats. We subjected rats to a controlled cortical impact model and used behavioral tests, histology, and immunofluorescence to assess whether flavonoid pinocembrin provides cerebral protection and improves functional recovery. Most importantly, we used multiple noninvasive structural, functional, and molecular MRI techniques to examine whether the pinocembrin-related neuroprotection and attenuation of neuroinflammation can be detected in vivo...
April 25, 2017: Brain, Behavior, and Immunity
https://www.readbyqxmd.com/read/28435103/magnetization-transfer-contrast-and-chemical-exchange-saturation-transfer-mri-features-and-analysis-of-the-field-dependent-saturation-spectrum
#15
Peter C M van Zijl, Wilfred W Lam, Jiadi Xu, Linda Knutsson, Greg J Stanisz
Magnetization Transfer Contrast (MTC) and Chemical Exchange Saturation Transfer (CEST) experiments measure the transfer of magnetization from molecular protons to the solvent water protons, an effect that becomes apparent as an MRI signal loss ("saturation"). This allows molecular information to be accessed with the enhanced sensitivity of MRI. In analogy to Magnetic Resonance Spectroscopy (MRS), these saturation data are presented as a function of the chemical shift of participating proton groups, e.g. OH, NH, NH2, which is called a Z-spectrum...
April 21, 2017: NeuroImage
https://www.readbyqxmd.com/read/28428213/clinically-feasible-microstructural-mri-to-quantify-cervical-spinal-cord-tissue-injury-using-dti-mt-and-t2-weighted-imaging-assessment-of-normative-data-and-reliability
#16
A R Martin, B De Leener, J Cohen-Adad, D W Cadotte, S Kalsi-Ryan, S F Lange, L Tetreault, A Nouri, A Crawley, D J Mikulis, H Ginsberg, M G Fehlings
BACKGROUND AND PURPOSE: DTI, magnetization transfer, T2*-weighted imaging, and cross-sectional area can quantify aspects of spinal cord microstructure. However, clinical adoption remains elusive due to complex acquisitions, cumbersome analysis, limited reliability, and wide ranges of normal values. We propose a simple multiparametric protocol with automated analysis and report normative data, analysis of confounding variables, and reliability. MATERIALS AND METHODS: Forty healthy subjects underwent T2WI, DTI, magnetization transfer, and T2*WI at 3T in <35 minutes using standard hardware and pulse sequences...
April 20, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28428212/a-novel-mri-biomarker-of-spinal-cord-white-matter-injury-t2-weighted-white-matter-to-gray-matter-signal-intensity-ratio
#17
A R Martin, B De Leener, J Cohen-Adad, D W Cadotte, S Kalsi-Ryan, S F Lange, L Tetreault, A Nouri, A Crawley, D J Mikulis, H Ginsberg, M G Fehlings
BACKGROUND AND PURPOSE: T2*-weighted imaging provides sharp contrast between spinal cord GM and WM, allowing their segmentation and cross-sectional area measurement. Injured WM demonstrates T2*WI hyperintensity but requires normalization for quantitative use. We introduce T2*WI WM/GM signal-intensity ratio and compare it against cross-sectional area, the DTI metric fractional anisotropy, and magnetization transfer ratio in degenerative cervical myelopathy. MATERIALS AND METHODS: Fifty-eight patients with degenerative cervical myelopathy and 40 healthy subjects underwent 3T MR imaging, covering C1-C7...
April 20, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28408961/the-usefulness-of-diagnostic-imaging-for-the-assessment-of-pain-symptoms-in-temporomandibular-disorders
#18
REVIEW
Shigeaki Suenaga, Kunihiro Nagayama, Taisuke Nagasawa, Hiroko Indo, Hideyuki J Majima
The causes of pain symptoms in the temporomandibular joint (TMJ) and masticatory muscle (MM) regions may not be determined by clinical examination alone. In this review, we document that pain symptoms of the TMJ and MM regions in patients with temporomandibular disorders (TMDs) are associated with computed tomography and magnetic resonance (MR) findings of internal derangement, joint effusion, osteoarthritis, and bone marrow edema. However, it is emphasized that these imaging findings must not be regarded as the unique and dominant factors in defining TMJ pain...
November 2016: Japanese Dental Science Review
https://www.readbyqxmd.com/read/28407330/diffusion-weighted-and-magnetization-transfer-imaging-in-testicular-spermatogenic-function-evaluation-preliminary-results
#19
Huanjun Wang, Jian Guan, Jinhua Lin, Zhongwei Zhang, Shurong Li, Yan Guo, Huasong Cai
PURPOSE: To assess the use of functional magnetic resonance imaging (MRI), including diffusion-weighted MRI (DWI) and magnetization transfer MRI (MTI) in evaluating male infertility. MATERIALS AND METHODS: Sixteen men with testicular spermatogenesis hypofunction confirmed by percutaneous testis biopsy and 31 volunteers (control group B, age range: 20-40 years) with normal semen analysis including younger (By, n = 15, age range: 20-30 years) and older (Bo, n = 16, age range: 31-40 years) men underwent pelvic 3T MRI, including DWI and MTI...
April 13, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28391789/microstructural-mr-imaging-techniques-in%C3%A2-multiple-sclerosis
#20
REVIEW
Massimo Filippi, Paolo Preziosa, Maria A Rocca
Due to its sensitivity in the detection of focal white matter (WM) lesions, MR imaging has become a paraclinical tool central to diagnosing multiple sclerosis (MS) and monitoring its evolution. Despite this, the correlation between patients' clinical status and conventional MR imaging measures is weak to moderate. Quantitative MR imaging-based techniques, such as magnetization transfer and diffusion tensor imaging, have a higher specificity toward the heterogeneous pathologic substrates of MS than MR imaging...
May 2017: Neuroimaging Clinics of North America
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