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"magnetization transfer"

Samuel Groeschel, Gisela E Hagberg, Thomas Schultz, Dávid Z Balla, Uwe Klose, Till-Karsten Hauser, Thomas Nägele, Oliver Bieri, Thomas Prasloski, Alex L MacKay, Ingeborg Krägeloh-Mann, Klaus Scheffler
OBJECTIVE: We investigate how known differences in myelin architecture between regions along the cortico-spinal tract and frontal white matter (WM) in 19 healthy adolescents are reflected in several quantitative MRI parameters that have been proposed to non-invasively probe WM microstructure. In a clinically feasible scan time, both conventional imaging sequences as well as microstructural MRI parameters were assessed in order to quantitatively characterise WM regions that are known to differ in the thickness of their myelin sheaths, and in the presence of crossing or parallel fibre organisation...
2016: PloS One
Jacob Anglister, Gautam Srivastava, Fred Naider
Intermolecular NOE interactions are invaluable for structure determination of biomolecular complexes by NMR and they represent the "gold-standard" amongst NMR measurements for characterizing interfaces. These NOEs constitute only a small fraction of the observed NOEs in a complex and are usually weaker than many of the intramolecular NOEs. A number of methods have been developed to remove the intramolecular NOEs that interfere with the identification of intermolecular NOEs. NMR experiments used to observe intermolecular NOE interactions in large protein complexes must cope with the short T2 relaxation time of the protons and heteronuclei in these complexes because they result in severe losses in sensitivity...
November 2016: Progress in Nuclear Magnetic Resonance Spectroscopy
DongKyu Lee, Sohyun Han, HyungJoon Cho
A variable repetition-delay (TR) spin echo sequence with repeated refocusing pulses, i.e., a variable TR turbo-spin echo (TSE), provides an attractive means of acquiring an accurate T1 map information that is free from gradient echo based artifacts such as magnetic field inhomogeneities particularly for ultra-high field (at 7T and above) preclinical applications. However, the applicability of multi-slice TSE sequences is often limited by signal distortion from T2 relaxation due to echo-train acquisitions for short T2 tissues, inter-slice cross talks and magnetization transfer (MT) from repetitive slice-selective 180° pulse, and extended scan times with multiple TR excitations...
November 10, 2016: Journal of Magnetic Resonance
Yang Zheng, Xiaoming Wang, Xuna Zhao
Purpose. This study aims to evaluate the process of brain development in neonates using combined amide proton transfer (APT) imaging and conventional magnetization transfer (MT) imaging. Materials and Methods. Case data were reviewed for all patients hospitalized in our institution's neonatal ward. Patients underwent APT and MT imaging (a single protocol) immediately following the routine MR examination. Single-slice APT/MT axial imaging was performed at the level of the basal ganglia. APT and MT ratio (MTR) measurements were performed in multiple brain regions of interest (ROIs)...
2016: BioMed Research International
David A Rudko, Mishkin Derakhshan, Josefina Maranzano, Kunio Nakamura, Douglas L Arnold, Sridar Narayanan
The purpose of our study was to evaluate the utility of measurements of cortical surface magnetization transfer ratio (csMTR) on the inner, mid and outer cortical boundaries as clinically accessible biomarkers of cortical gray matter pathology in multiple sclerosis (MS). Twenty-five MS patients and 12 matched controls were recruited from the MS Clinic of the Montreal Neurological Institute. Anatomical and magnetization transfer ratio (MTR) images were acquired using 3 Tesla MRI at baseline and two-year time-points...
2016: NeuroImage: Clinical
Jimin Ren, A Dean Sherry, Craig R Malloy
PURPOSE: To develop an efficient (31) P magnetic resonance spectroscopy (MRS) method for measuring creatine kinase (CK) activity, adenosine triphosphate (ATP) synthesis, and motion dynamics in the human brain at 7 Tesla (T). METHODS: Three band inversion modules differing in center frequency were used to induce magnetization transfer (MT) effect in three exchange pathways: (i) CK-mediated reaction PCr → γ-ATP; (ii) de novo ATP synthesis Pi → γ-ATP; and (iii) ATP intramolecular (31) P-(31) P cross-relaxation γ-(α-) ↔ β-ATP...
November 20, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Gopal Varma, Olivier M Girard, Valentin H Prevost, Aaron K Grant, Guillaume Duhamel, David C Alsop
PURPOSE: This paper describes a technique that can be used in vivo to measure the dipolar relaxation time, T1D , of macromolecular protons contributing to magnetization transfer (MT) in tissues and to produce quantitative T1D maps. THEORY AND METHODS: The technique builds upon the inhomogeneous MT (ihMT) technique that is particularly sensitive to tissue components with long T1D . A standard ihMT experiment was altered to introduce a variable time for switching between positive and negative offset frequencies for RF saturation...
November 17, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Athina C Tsili, Alexandra Ntorkou, Dimitrios Giannakis, Nikolaos Sofikitis, Maria I Argyropoulou
BACKGROUND: In humans, the left testis generally hangs lower than the right and the right is larger than the left. Magnetic resonance imaging (MRI) represents an important adjuvant modality in the investigation of testicular diseases. PURPOSE: To assess if normal testes asymmetry is related to apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR). MATERIAL AND METHODS: The normal testes from 106 men were included. Testicular volume (TV) was calculated by using the ellipsoid formula: length × width × height × 0...
November 17, 2016: Acta Radiologica
Mina Park, Won-Jin Moon
With the rise of aging population, clinical concern and research attention has shifted towards neuroimaging of dementia. The advent of 3T, magnetic resonance imaging (MRI) has permitted the anatomical imaging of neurodegenerative disease, specifically dementia, with improved resolution. Furthermore, more powerful techniques such as diffusion tensor imaging, quantitative susceptibility mapping, and magnetic transfer imaging have successfully emerged for the detection of micro-structural abnormalities. In the present review article, we provide a brief overview of Alzheimer's disease and explore recent neuroimaging developments in the field of dementia with an emphasis on structural MR imaging in order to propose a simple and easily applicable systematic approach to the imaging diagnosis of dementia...
November 2016: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
Z Chen, W Peng, H Sun, W Kuang, W Li, Z Jia, Q Gong
Previous structural imaging studies have found evidence of brain morphometric changes in patients with major depressive disorder (MDD), but these studies rarely excluded compounding effects of certain important factors, such as medications and long duration of illnesses. Furthermore, the neurobiological mechanism of the macroscopic findings of structural alterations in MDD patients remains unclear. In this study, we utilized magnetization transfer imaging, a quantitative measure of the macromolecular structural integrity of brain tissue, to identify biophysical alterations, which are represented by a magnetization transfer ratio (MTR), in MDD patients...
November 8, 2016: Translational Psychiatry
Xiangyong Tang, Zhuozhi Dai, Gang Xiao, Gen Yan, Zhiwei Shen, Tao Zhang, Guishan Zhang, Zerui Zhuang, Yuanyu Shen, Zhiyan Zhang, Wei Hu, Renhua Wu
Glioma is a malignant neoplasm affecting the central nervous system. The conventional approaches to diagnosis, such as T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and contrast-enhanced T1WI, give an oversimplified representation of anatomic structures. Nuclear Overhauser enhancement (NOE) imaging is a special form of magnetization transfer (MT) that provides a new way to detect small solute pools through indirect measurement of attenuated water signals, and makes it possible to probe semi-solid macromolecular protons...
October 28, 2016: ACS Chemical Neuroscience
Martina F Callaghan, Siawoosh Mohammadi, Nikolaus Weiskopf
Quantitative MRI (qMRI) provides standardized measures of specific physical parameters that are sensitive to the underlying tissue microstructure and are a first step towards achieving maps of biologically relevant metrics through in vivo histology using MRI. Recently proposed models have described the interdependence of qMRI parameters. Combining such models with the concept of image synthesis points towards a novel approach to synthetic qMRI, in which maps of fundamentally different physical properties are constructed through the use of biophysical models...
October 18, 2016: NMR in Biomedicine
P Goossens, C Martineau-Corcos, F Saïdi, J A Martens, F Taulelle
Nafion proton exchange membranes (PEMs) for fuel cell applications are extensively studied and commercially applied, but their unique proton conduction capabilities are still somewhat unexplained. For studying proton dynamics in situ, molecular level spectroscopic techniques have been of limited utility so far. By solid-state (1)H and (19)F double resonance nuclear magnetic resonance (NMR) spectroscopy using the recently revived multiple contact cross-polarization (MC-CP) pulse sequence along with double-quantum (1)H-(1)H filtering, high resolution proton populations distinct from the dominant water resonance were observed in Nafion for the first time...
October 7, 2016: Physical Chemistry Chemical Physics: PCCP
Tiago Teixeira, Tarik Hafyane, Nikola Stikov, Cansu Akdeniz, Andreas Greiser, Matthias G Friedrich
BACKGROUND: T1 mapping based on cardiovascular magnetic resonance (CMR) is a novel approach using the magnetic relaxation T1 time as a quantitative marker for myocardial tissue composition. Various T1 mapping sequences are being used, with different strengths and weaknesses. Data comparing different sequences head to head however are sparse. METHODS: We compared three T1 mapping sequences, ShMOLLI, MOLLI and SASHA in phantoms and in a mid-ventricular slice of 40 healthy individuals (mean age 59 ± 7 years, 45 % male) with low (68 %) or moderate cardiovascular risk...
October 4, 2016: Journal of Cardiovascular Magnetic Resonance
Gautam Srivastava, Adi Moseri, Naama Kessler, Sabine R Akabayov, Boris Arshava, Fred Naider, Jacob Anglister
Weak protein-protein and protein-ligand interactions play important roles in biological recognition. In many cases, simplification of structural studies of large protein complexes is achieved by investigation of the interaction between the protein and a weakly binding segment of its protein ligand. Detection of pairwise interactions in such complexes is a major challenge for both X-ray crystallography and nuclear magnetic resonance. We demonstrate that transferred nuclear Overhauser effect (TRNOE), in combination with asymmetric deuteration of a protein and a peptide ligand can be used to detect intermolecular interactions in large protein complexes with molecular weights up to ~ 100 kDa...
November 2016: FEBS Journal
Daniel Ontaneda, Robert J Fox
Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system. Magnetic resonance imaging (MRI) is sensitive to lesion formation both in the brain and spinal cord. Imaging plays a prominent role in the diagnosis and monitoring of MS. Over a dozen anti-inflammatory therapies are approved for MS and the development of many of these medications was made possible through the use of contrast-enhancing lesions on MRI as a phase II outcome. A similar phase II outcome method for the neurodegeneration that underlies progressive courses of the disease is still unavailable...
October 3, 2016: Neurotherapeutics: the Journal of the American Society for Experimental NeuroTherapeutics
Kai Jiang, Christopher M Ferguson, Behzad Ebrahimi, Hui Tang, Timothy L Kline, Tyson A Burningham, Prassana K Mishra, Joseph P Grande, Slobodan I Macura, Lilach O Lerman
Purpose To test the utility of magnetization transfer imaging in detecting and monitoring the progression of renal fibrosis in mice with unilateral renal artery stenosis. Materials and Methods This prospective study was approved by the Institutional Animal Care and Use Committee. Renal artery stenosis surgery (n = 10) or sham surgery (n = 5) was performed, and the stenotic and contralateral kidneys were studied longitudinally in vivo at baseline and 2, 4, and 6 weeks after surgery. After a 16.4-T magnetic resonance imaging examination, magnetization transfer ratio was measured as an index of fibrosis (guided by parameters selected in preliminary phantom studies)...
October 3, 2016: Radiology
Randall B Stafford, Myung-Kyun Woo, Se-Hong Oh, Sudipto Dolui, Tiejun Zhao, Young-Bo Kim, John A Detre, Zang-Hee Cho, Jongho Lee
7 T arterial spin labeling (ASL) faces major challenges including the increased specific absorption rate (SAR) and increased B0 and B1 inhomogeneity. This work describes the design and implementation of a dual-coil system that allows for continuous ASL (CASL) at 7 T. This system consisted of an actively detunable eight-channel transceiver head coil, and a three-channel transceiver labeling coil. Four experiments were performed in 5 healthy subjects: (i) to demonstrate that active detuning during ASL labeling reduces magnetization transfer; (ii) to measure the B1 profile at the labeling plane; (iii) to quantify B0 off-resonance at the labeling plane; and (iv) to collect in vivo CASL data...
June 2016: International Journal of Imaging Systems and Technology
James M Elliott, Sudarshan Dayanidhi, Charles Hazle, Mark A Hoggarth, Jacob McPherson, Cheryl L Sparks, Kenneth A Weber
Synopsis It is generally accepted that up to 50% of those with a whiplash injury following a motor vehicle collision will fail to fully recover. Twenty-five percent of these patients will demonstrate a markedly complex clinical picture that includes severe pain-related disability, sensory and motor disturbances, and psychological distress. A number of psychosocial factors have shown prognostic value for recovery following whiplash from a motor vehicle collision. To date, no management approach (eg, physical therapies, education, psychological interventions, or interdisciplinary strategies) for acute whiplash has positively influenced recovery rates...
October 2016: Journal of Orthopaedic and Sports Physical Therapy
Giuseppe Muscogiuri, Wolfgang G Rehwald, U Joseph Schoepf, Pal Suranyi, Sheldon E Litwin, Carlo N De Cecco, Julian L Wichmann, Stefanie Mangold, Damiano Caruso, Stephen R Fuller, Richard R Bayer 2nd, Akos Varga-Szemes
PURPOSE: To evaluate a new dark-blood late gadolinium enhancement (LGE) technique called "T(Rho) And Magnetization transfer and INvErsion Recovery" (TRAMINER) for the ability to detect myocardial LGE versus standard "bright-blood" inversion recovery (SIR) imaging. MATERIALS AND METHODS: This Institutional Review Board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant prospective study included 40 patients (62 ± 14 years [mean ± standard deviation (SD)], 29 males) with suspected myocardial infarction (MI) referred for the assessment of myocardial viability...
September 30, 2016: Journal of Magnetic Resonance Imaging: JMRI
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