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Relaxometry

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https://www.readbyqxmd.com/read/28090441/principal-component-analysis-t1%C3%AF-voxel-based-relaxometry-of-the-articular-cartilage-a-comparison-of-biochemical-patterns-in-osteoarthritis-and-anterior-cruciate-ligament-subjects
#1
Valentina Pedoia, Colin Russell, Allison Randolph, Xiaojuan Li, Sharmila Majumdar
BACKGROUND: Quantitative MR, including T1ρ mapping, has been extensively used to probe early biochemical changes in knee articular cartilage of subjects with osteoarthritis (OA) and others at risk for cartilage degeneration, such as those with anterior cruciate ligament (ACL) injury and reconstruction. However, limited studies have been performed aimed to assess the spatial location and patterns of T1ρ. In this study we used a novel voxel-based relaxometry (VBR) technique coupled with principal component analysis (PCA) to extract relevant features so as to describe regional patterns and to investigate their similarities and differences in T1ρ maps in subjects with OA and subjects six months after ACL reconstruction (ACLR)...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28074498/imaging-and-t2-relaxometry-of-short-t2-connective-tissues-in-the-knee-using-ultrashort-echo-time-double-echo-steady-state-utedess
#2
Akshay S Chaudhari, Bragi Sveinsson, Catherine J Moran, Emily J McWalter, Ethan M Johnson, Tao Zhang, Garry E Gold, Brian A Hargreaves
PURPOSE: To develop a radial, double-echo steady-state (DESS) sequence with ultra-short echo-time (UTE) capabilities for T2 measurement of short-T2 tissues along with simultaneous rapid, signal-to-noise ratio (SNR)-efficient, and high-isotropic-resolution morphological knee imaging. METHODS: THe 3D radial UTE readouts were incorporated into DESS, termed UTEDESS. Multiple-echo-time UTEDESS was used for performing T2 relaxometry for short-T2 tendons, ligaments, and menisci; and for Dixon water-fat imaging...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28072579/development-of-advanced-signal-processing-and-source-imaging-methods-for-superparamagnetic-relaxometry
#3
Ming-Xiong Huang, Bill Anderson, Charles W Huang, Gerd J Kunde, Erika C Vreeland, Jeffrey W Huang, Andrei N Matlashov, Todor Karaulanov, Christopher P Nettles, Andrew Gomez, Kayla Minser, Caroline Weldon, Giulio Paciotti, Michael Harsh, Roland R Lee, Edward R Flynn
Superparamagnetic relaxometry (SPMR) is a highly sensitive technique for the in vivo detection of tumor cells and may improve early stage detection of cancers. SPMR employs superparamagnetic iron oxide nanoparticles (SPION). After a brief magnetizing pulse is used to align the SPION, SPMR measures the time decay of SPION using super-conducting quantum interference device (SQUID) sensors. Substantial research has been carried out in developing the SQUID hardware and in improving the properties of the SPION. However, little research has been done in the pre-processing of sensor signals and post-processing source modeling in SPMR...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28069115/metabolism-variation-and-better-storability-of-dark-versus-light-coloured-soybean-glycine-max-l-merr-seeds
#4
Jiang Liu, Wen-Ting Qin, Hai-Jun Wu, Cai-Qiong Yang, Jun-Cai Deng, Nasir Iqbal, Wei-Guo Liu, Jun-Bo Du, Kai Shu, Feng Yang, Xiao-Chun Wang, Tai-Wen Yong, Wen-Yu Yang
The effects of storage duration on the seed germination and metabolite profiling of soybean seeds with five different coloured coats were studied. Their germination, constituents and transcript expressions of isoflavones and free fatty acids (FFAs) were compared using chromatographic metabolomic profiling and transcriptome sequencing. The seed water content was characterized using nuclear magnetic resonance (NMR) relaxometry. Results showed that dark-coloured seeds were less inactivated than light-coloured seeds...
May 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28040654/verification-of-the-authenticity-of-drugs-by-means-of-nmr-relaxometry-viagra-%C3%A2-as-an-example
#5
S Wilczyńki, M Petelenz, M Florek-Wojciechowska, S Kulesza, Sz Brym, B Błońska-Fajfrowska, D Kruk
(1)H spin-lattice Nuclear Magnetic Resonance (NMR) relaxometry, vibrational spectroscopy and Atomic Force Microscopy (AFM) have been applied to differentiate between original and counterfeit Viagra(®). The relaxation studies have been performed in a frequency range covering four orders of magnitude, from 4kHz to 40MHz. It has been shown that for the counterfeit product the relaxation is bi-exponential in the whole frequency range, while for the original Viagra(®) the relaxation process is always single exponential...
December 23, 2016: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28040490/biological-effects-of-iron-oxide-protamine-sulfate-complex-on-mesenchymal-stem-cells-and-its-relaxometry-based-labeling-optimization-for-cellular-mri
#6
Sushanta Kumar Mishra, Subash Khushu, Gurudutta Gangenahalli
Mesenchymal stem cells (MSCs) are frequently used as a therapeutic, but reliable imaging technique to longitudinally evaluate the engraftment of transplanted cells is inadequate. For magnetic resonance imaging (MRI), it is essential to understand the technical competence of in vitro stem cells labeling with iron oxide with regard to its relaxation behavior and significance of its biological expressions. The purpose of the study was to optimize the effective labeling of MSCs with high transverse relaxivity iron oxide contrast agent with protamine sulfate and also evaluate the biological effects (phenotype and function) of labeled MSCs...
December 28, 2016: Experimental Cell Research
https://www.readbyqxmd.com/read/28034994/mr-fingerprinting-of-adult-brain-tumors-initial-experience
#7
C Badve, A Yu, S Dastmalchian, M Rogers, D Ma, Y Jiang, S Margevicius, S Pahwa, Z Lu, M Schluchter, J Sunshine, M Griswold, A Sloan, V Gulani
BACKGROUND AND PURPOSE: MR fingerprinting allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assessed the utility of MR fingerprinting in differentiating common types of adult intra-axial brain tumors. MATERIALS AND METHODS: MR fingerprinting acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 World Health Organization grade II lower grade gliomas, and 8 metastases. T1, T2 of the solid tumor, immediate peritumoral white matter, and contralateral white matter were summarized within each ROI...
December 29, 2016: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28028868/neurometabolic-profiles-of-the-substantia-nigra-and-striatum-of-mptp-intoxicated-common-marmosets-an-in-vivo-proton-mrs-study-at-9-4%C3%A2-t
#8
Hwon Heo, Jae-Bum Ahn, Hyeong Hun Lee, Euna Kwon, Jun-Won Yun, Hyeonjin Kim, Byeong-Cheol Kang
Given the strong coupling between the substantia nigra (SN) and striatum (STR) in the early stage of Parkinson's disease (PD), yet only a few studies reported to date that have simultaneously investigated the neurochemistry of these two brain regions in vivo, we performed longitudinal metabolic profiling in the SN and STR of 1-methyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated common marmoset monkey models of PD (n = 10) by using proton MRS ((1) H-MRS) at 9.4 T. T2 relaxometry was also performed in the SN by using MRI...
December 28, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/28024257/evaluation-of-sandstone-surface-relaxivity-using-laser-induced-breakdown-spectroscopy
#9
Kathryn E Washburn, Magdalena Sandor, Yuesheng Cheng
Nuclear magnetic resonance (NMR) relaxometry is a common technique used to assess the pore size of fluid-filled porous materials in a wide variety of fields. However, the NMR signal itself only provides a relative distribution of pore size. To calculate an absolute pore size distribution from the NMR data, the material's surface relaxivity needs to be known. Here, a method is presented using laser-induced breakdown spectroscopy (LIBS) to evaluate surface relaxivity in sandstones. NMR transverse and longitudinal relaxation was measured on a set of sandstone samples and the surface relaxivity was calculated from the pore size distribution determined with MICP measurements...
December 9, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28019018/contrast-mechanisms-associated-with-neuromelanin-mri
#10
Paula Trujillo, Paul E Summers, Emanuele Ferrari, Fabio A Zucca, Michela Sturini, Luca T Mainardi, Sergio Cerutti, Alex K Smith, Seth A Smith, Luigi Zecca, Antonella Costa
PURPOSE: To investigate the physical mechanisms associated with the contrast observed in neuromelanin MRI. METHODS: Phantoms having different concentrations of synthetic melanins with different degrees of iron loading were examined on a 3 Tesla scanner using relaxometry and quantitative magnetization transfer (MT). RESULTS: Concentration-dependent T1 and T2 shortening was most pronounced for the melanin pigment when combined with iron. Metal-free melanin had a negligible effect on the magnetization transfer spectra...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28006675/the-inversion-of-2d-nmr-relaxometry-data-using-l1-regularization
#11
Xiaolong Zhou, Guanqun Su, Lijia Wang, Shengdong Nie, Xinmin Ge
NMR relaxometry has been used as a powerful tool to study molecular dynamics. Many algorithms have been developed for the inversion of 2D NMR relaxometry data. Unlike traditional algorithms implementing L2 regularization, high order Tikhonov regularization or iterative regularization, L1 penalty term is involved to constrain the sparsity of resultant spectra in this paper. Then fast iterative shrinkage-thresholding algorithm (FISTA) is proposed to solve the L1 regularization problem. The effectiveness, noise vulnerability and practical utility of the proposed algorithm are analyzed by simulations and experiments...
December 9, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28003711/compact-nmr-relaxometry-of-human-blood-and-blood-components
#12
David P Cistola, Michelle D Robinson
Nuclear magnetic resonance relaxometry is a uniquely practical and versatile implementation of NMR technology. Because it does not depend on chemical shift resolution, it can be performed using low-field compact instruments deployed in atypical settings. Early relaxometry studies of human blood were focused on developing a diagnostic test for cancer. Those efforts were misplaced, as the measurements were not specific to cancer. However, important lessons were learned about the factors that drive the water longitudinal (T1) and transverse (T2) relaxation times...
November 2016: Trends in Analytical Chemistry: TRAC
https://www.readbyqxmd.com/read/28000023/extreme-dehydration-observed-in-antarctic-turgidosculum-complicatulum-and-in-prasiola-crispa
#13
M Bacior, P Nowak, H Harańczyk, S Patryas, P Kijak, A Ligęzowska, M A Olech
Gaseous phase hydration effect of extremely dehydrated thallus of the Antarctic lichenized fungus Turgidosculum complicatulum and of green alga Prasiola crispa was observed using hydration kinetics, sorption isotherm, (1)H-NMR spectroscopy and relaxometry. Three bound water fractions were distinguished: (1) very tightly bound water, (2) tightly bound water and (3) a loosely bound water fraction detected at higher levels of hydration. Sorption isotherm was sigmoidal in form and well fitted using Dent model. The relative mass of water saturating primary water binding sites was ΔM/m 0 = 0...
December 20, 2016: Extremophiles: Life Under Extreme Conditions
https://www.readbyqxmd.com/read/27937040/multiparametric-or-practical-quantitative-liver-mri-towards-millisecond-fat-fraction-kilopascal-and-function-era
#14
Emre Unal, Ilkay Sedakat Idilman, Muşturay Karçaaltıncaba
New advances in liver magnetic resonance imaging (MRI) may enable diagnosis of unseen pathologies by conventional techniques. Normal T1 (550-620 ms for 1.5 T and 700-850 ms for 3 T), T2, T2* (>20 ms), T1rho (40-50 ms) mapping, proton density fat fraction (PDFF) (≤5%) and stiffness (2-3kPa) values can enable differentiation of a normal liver from chronic liver and diffuse diseases. Gd-EOB-DTPA can enable assessment of liver function by using postcontrast hepatobiliary phase or T1 reduction rate (normally above 60%)...
February 2017: Expert Review of Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/27920897/impact-of-biopolymer-matrices-on-relaxometric-properties-of-contrast-agents
#15
Alfonso Maria Ponsiglione, Maria Russo, Paolo Antonio Netti, Enza Torino
Properties of water molecules at the interface between contrast agents (CAs) for magnetic resonance imaging and macromolecules could have a valuable impact on the effectiveness of metal chelates. Recent studies, indeed, demonstrated that polymer architectures could influence CAs' relaxivity by modifying the correlation times of the metal chelate. However, an understanding of the physico-chemical properties of polymer/CA systems is necessary to improve the efficiency of clinically used CAs, still exhibiting low relaxivity...
December 6, 2016: Interface Focus
https://www.readbyqxmd.com/read/27910860/dynamic-nuclear-magnetic-resonance-field-sensing-with-part-per-trillion-resolution
#16
Simon Gross, Christoph Barmet, Benjamin E Dietrich, David O Brunner, Thomas Schmid, Klaas P Pruessmann
High-field magnets of up to tens of teslas in strength advance applications in physics, chemistry and the life sciences. However, progress in generating such high fields has not been matched by corresponding advances in magnetic field measurement. Based mostly on nuclear magnetic resonance, dynamic high-field magnetometry is currently limited to resolutions in the nanotesla range. Here we report a concerted approach involving tailored materials, magnetostatics and detection electronics to enhance the resolution of nuclear magnetic resonance sensing by three orders of magnitude...
December 2, 2016: Nature Communications
https://www.readbyqxmd.com/read/27904982/magnetic-resonance-evaluation-of-cardiac-thrombi-and-masses-by-t1-and-t2-mapping-an-observational-study
#17
Thibault Caspar, Soraya El Ghannudi, Mickaël Ohana, Aïssam Labani, Aubrietia Lawson, Patrick Ohlmann, Olivier Morel, Michel De Mathelin, Catherine Roy, Afshin Gangi, Philippe Germain
The purpose of this work was to evaluate CMR T1 and T2 mapping sequences in patients with intracardiac thrombi and masses in order to assess T1 and T2 relaxometry usefulness and to allow better etiological diagnosis. This observational study of patients scheduled for routine CMR was performed from September 2014 to August 2015. All patients referred to our department for a 1.5 T CMR were screened to participate. T1 mapping were acquired before and after Gadolinium injection; T2 mapping images were obtained before injection...
December 1, 2016: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/27903016/predicting-tissue-breaking-strengths-in-the-epileptic-brain-with-t2-relaxometry-application-of-pulsed-water-jet-dissection-system-for-epilepsy-surgery
#18
Yoko Takahashi, Masaki Iwasaki, Atsuhiro Nakagawa, Shiho Sato, Nobukazu Nakasato, Teiji Tominaga
Background The piezo actuator-driven pulsed water jet (ADPJ) system is a novel surgical instrument that enables dissection of tissue without thermal damage. Using the ADPJ system in epilepsy surgery requires prediction of the tissue breaking strength of the epileptic brain. The aim of this study was to elucidate whether magnetic resonance imaging T2 relaxometry could predict the breaking strength. Methods A total of 12 patients with drug-resistant temporal lobe epilepsy who received surgical treatment were included in the study...
November 30, 2016: Journal of Neurological Surgery. Part A, Central European Neurosurgery
https://www.readbyqxmd.com/read/27893386/optimizing-mr-scan-design-for-model-based-t1-t2-estimation-from-steady-state-sequences
#19
Gopal Nataraj, Jon-Fredrick Nielsen, Jeffrey Fessler
Rapid, reliable quantification of MR relaxation parameters T1 and T2 is desirable for many clinical applications. Steady-state sequences such as Spoiled Gradient-Recalled Echo (SPGR) and Dual-Echo Steady-State (DESS) are fast and wellsuited for relaxometry because the signals they produce are quite sensitive to T1 and T2 variation. However, T1, T2 estimation with these sequences typically requires multiple scans with varied sets of acquisition parameters. This paper describes a systematic framework for selecting scan types (e...
October 4, 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/27862590/hepatic-gadoxetic-acid-uptake-as-a-measure-of-diffuse-liver-disease-where-are-we
#20
REVIEW
Ahmed Ba-Ssalamah, Nina Bastati, Andreas Wibmer, Romana Fragner, Jacqueline C Hodge, Michael Trauner, Christian J Herold, Mustafa R Bashir, Bernard E Van Beers
: MRI has emerged as the most comprehensive noninvasive diagnostic tool for focal liver lesions and diffuse hepatobiliary disorders. The introduction of hepatobiliary contrast agents, most notably gadoxetic acid (GA), has expanded the role of MRI, particularly in the functional imaging of chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD). GA-enhanced MRI (GA-MRI) may help to distinguish between the two subgroups of NAFLD, simple steatosis and nonalcoholic steatohepatitis...
November 8, 2016: Journal of Magnetic Resonance Imaging: JMRI
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