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Chemical exchange saturation transfer

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https://www.readbyqxmd.com/read/29780447/fluorinated-eu-ii-based-multimodal-contrast-agent-for-temperature-and-redox-responsive-magnetic-resonance-imaging
#1
Lina A Basal, Matthew D Bailey, Jonathan Romero, Meser M Ali, Lyazat Kurenbekova, Jason Yustein, Robia G Pautler, Matthew J Allen
Magnetic resonance imaging (MRI) using redox-active, EuII -containing complexes is one of the most promising techniques for noninvasively imaging hypoxia in vivo . In this technique, positive ( T 1 -weighted) contrast enhancement persists in areas of relatively low oxidizing ability, such as hypoxic tissue. Herein, we describe a fluorinated, EuII -containing complex in which the redox-active metal is caged by intramolecular interactions. The position of the fluorine atoms enables temperature-responsive contrast enhancement in the reduced form of the contrast agent and detection of the oxidized contrast agent via MRI in vivo ...
December 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29761413/comparison-of-b-0-versus-b-0-and-b-1-field-inhomogeneity-correction-for-glycosaminoglycan-chemical-exchange-saturation-transfer-imaging
#2
Anja Müller-Lutz, Alexandra Ljimani, Julia Stabinska, Moritz Zaiss, Johannes Boos, Hans-Jörg Wittsack, Christoph Schleich
PURPOSE: The study compares glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging of intervertebral discs corrected for solely B0 inhomogeneities or both B0 and B1 inhomogeneities. METHODS: Lumbar intervertebral discs of 20 volunteers were examined with T2 -weighted and gagCEST imaging. Field inhomogeneity correction was performed with B0 correction only and with correction of both B0 and B1 . GagCEST effects measured by the asymmetric magnetization transfer ratio (MTRasym ) and signal-to-noise ratio (SNR) were compared between both methods...
May 14, 2018: Magma
https://www.readbyqxmd.com/read/29756286/rapid-and-quantitative-chemical-exchange-saturation-transfer-cest-imaging-with-magnetic-resonance-fingerprinting-mrf
#3
Ouri Cohen, Shuning Huang, Michael T McMahon, Matthew S Rosen, Christian T Farrar
PURPOSE: To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging. METHODS: We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the Nα -amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6)...
May 13, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29753980/exploring-methods-to-expedite-the-recording-of-cest-datasets-using-selective-pulse-excitation
#4
Tairan Yuwen, Guillaume Bouvignies, Lewis E Kay
Chemical Exchange Saturation Transfer (CEST) has emerged as a powerful tool for studies of biomolecular conformational exchange involving the interconversion between a major, visible conformer and one or more minor, invisible states. Applications typically entail recording a large number of 2D datasets, each of which differs in the position of a weak radio frequency field, so as to generate a CEST profile for each nucleus from which the chemical shifts of spins in the invisible state(s) are obtained. Here we compare a number of band-selective CEST schemes for speeding up the process using either DANTE or cosine-modulated excitation approaches...
April 26, 2018: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/29749579/in-vivo-detection-of-acute-intracellular-acidification-in-glioblastoma-multiforme-following-a-single-dose-of-cariporide
#5
Mohammed Albatany, Alex Li, Susan Meakin, Robert Bartha
Glioblastoma is an aggressive brain cancer that is very difficult to treat. Clinically, it is important to be able to distinguish aggressive from non-aggressive brain tumors. Previous studies have shown that some drugs can induce a rapid change in intracellular pH that could help to identify aggressive cancer. The sodium proton exchanger (NHE1) plays a significant role in maintaining pH balance in the tumor microenvironment. Cariporide is a sodium proton exchange inhibitor that is well tolerated by humans in cardiac applications...
May 10, 2018: International Journal of Clinical Oncology
https://www.readbyqxmd.com/read/29748204/a-qualitative-and-quantitative-correlation-study-of-lumbar-intervertebral-disc-degeneration-using-glycosaminoglycan-chemical-exchange-saturation-transfer-pfirrmann-grade-and-t1-%C3%AF
#6
O Togao, A Hiwatashi, T Wada, K Yamashita, K Kikuchi, C Tokunaga, J Keupp, M Yoneyama, H Honda
BACKGROUND AND PURPOSE: Glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging allows the direct measurement and mapping of glycosaminoglycans. In this study, we aimed to evaluate the usefulness of gagCEST imaging in the quantitative assessment of intervertebral disc degeneration in a comparison with Pfirrmann grade and T1-ρ measurements. MATERIALS AND METHODS: Ninety-six lumbar intervertebral discs in 24 volunteers (36.0 ± 8.5 years of age, 21 men and 3 women) were examined with both gagCEST imaging and T1-ρ measurements...
May 10, 2018: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/29733378/assessing-the-predictability-of-idh-mutation-and-mgmt-methylation-status-in-glioma-patients-using-relaxation-compensated-multi-pool-cest-mri-at-7-0-tesla
#7
Daniel Paech, Johannes Windschuh, Johanna Oberhollenzer, Constantin Dreher, Felix Sahm, Jan-Eric Meissner, Steffen Goerke, Patrick Schuenke, Moritz Zaiss, Sebastian Regnery, Sebastian Bickelhaupt, Philipp Bäumer, Martin Bendszus, Wolfgang Wick, Andreas Unterberg, Peter Bachert, Mark Edward Ladd, Heinz-Peter Schlemmer, Alexander Radbruch
Background: Early identification of prognostic superior characteristics in glioma patients such as Isocitrate dehydrogenase(IDH)-mutation and O6-methylguanine-DNA-methyltransferase (MGMT) promotor methylation status is of great clinical importance. The study purpose was to investigate the non-invasive predictability of IDH-mutation status, MGMT promotor methylation, and differentiation of lower versus higher grade glioma (LGG vs. HGG) in newly-diagnosed patients employing relaxation-compensated multi-pool Chemical Exchange Saturation Transfer (CEST) magnetic resonance imaging (MRI) at 7...
May 4, 2018: Neuro-oncology
https://www.readbyqxmd.com/read/29727175/interaction-of-huntingtin-exon-1-peptides-with-lipid-based-micellar-nanoparticles-probed-by-solution-nmr-and-q-band-pulsed-epr
#8
Alberto Ceccon, Thomas Schmidt, Vitali Tugarinov, Samuel A Kotler, Charles D Schwieters, G Marius Clore
Lipid-based micellar nanoparticles promote aggregation of huntingtin exon-1 peptides. Here we characterize the interaction of two such peptides, httNTQ7 and httNTQ10 comprising the N-terminal amphiphilic domain of huntingtin followed by 7 and 10 glutamine repeats, respectively, with 8 nm lipid micelles using NMR chemical exchange saturation transfer (CEST), circular dichroism and pulsed Q-band EPR. Exchange between free and micelle-bound httNTQn peptides occurs on the millisecond time scale with a KD ~ 0.5-1 mM...
May 4, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29713308/-in-vivo-multimodal-magnetic-resonance-imaging-changes-after-n-methyl-d-aspartate-triggered-spasms-in-infant-rats
#9
Minyoung Lee, Mi-Sun Yum, Dong-Cheol Woo, Woo-Hyun Shim, Tae-Sung Ko, Libor Velíšek
Objective: Despite the serious neurodevelopmental sequelae of epileptic encephalopathy during infancy, the pathomechanisms involved remain unclear. To find potential biomarkers that can reflect the pathogenesis of epileptic encephalopathy, we explored the neurometabolic and microstructural sequelae after infantile spasms using a rat model of infantile spasms and in vivo magnetic resonance imaging techniques. Methods: Rats prenatally exposed to betamethasone were subjected to three rounds of intraperitoneal N -methyl-d-aspartate (NMDA) triggering of spasms or received saline injections (controls) on postnatal days (P) 12, 13, and 15...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29672976/dual-frequency-irradiation-cest-mri-of-endogenous-bulk-mobile-proteins
#10
Steffen Goerke, Johannes Breitling, Moritz Zaiss, Johannes Windschuh, Patrick Kunz, Patrick Schuenke, Daniel Paech, Dario L Longo, Karel D Klika, Mark E Ladd, Peter Bachert
A novel MRI contrast is proposed which enables the selective detection of endogenous bulk mobile proteins in vivo. Such a non-invasive imaging technique may be of particular interest for many diseases associated with pathological alterations of protein expression, such as cancer and neurodegenerative disorders. Specificity to mobile proteins was achieved by the selective measurement of intramolecular spin diffusion and the removal of semi-solid macromolecular signal components by a correction procedure. For this purpose, the approach of chemical exchange saturation transfer (CEST) was extended to a radiofrequency (RF) irradiation scheme at two different frequency offsets (dualCEST)...
April 19, 2018: NMR in Biomedicine
https://www.readbyqxmd.com/read/29672812/cartilage-imaging-techniques-and-developments
#11
Edwin H G Oei, Marius C Wick, Anja Müller-Lutz, Christoph Schleich, Falk R Miese
Cartilage degeneration is one of the most common chronic age-related joint disorders leading to pain and reduced joint motion. The increasing prevalence of osteoarthritis requires accurate cartilage imaging, both clinically and in research. Detailed cartilage imaging is also necessary for traumatic cartilage lesions and for pre- and postoperative assessment of cartilage repair procedures. Although still widely used, conventional radiography bears significant limitations because it assesses cartilage indirectly by joint space width...
April 2018: Seminars in Musculoskeletal Radiology
https://www.readbyqxmd.com/read/29663694/dramatic-decrease-in-cest-measurement-times-using-multi-site-excitation
#12
Tairan Yuwen, Lewis E Kay, Guillaume Bouvignies
Chemical exchange saturation transfer (CEST) has recently evolved into a powerful approach for studying sparsely populated, "invisible" protein states in slow exchange with a major, visible conformer. Central to the technique is the use of a weak, highly selective radio-frequency field that is applied at different frequency offsets in successive experiments, "searching" for minor state resonances. The recording of CEST profiles with enough points to ensure coverage of the entire spectrum at sufficient resolution can be time-consuming, especially for applications that require high static magnetic-fields or when small chemical shift differences between exchanging states must be quantified...
April 17, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29662912/relationship-between-quantitative-mri-biomarkers-and-patient-reported-outcome-measures-after-cartilage-repair-surgery-a-systematic-review
#13
REVIEW
Drew A Lansdown, Kevin Wang, Eric Cotter, Annabelle Davey, Brian J Cole
Background: Treatment of articular cartilage injuries remains a clinical challenge, and the optimal tools to monitor and predict clinical outcomes are unclear. Quantitative magnetic resonance imaging (qMRI) allows for a noninvasive biochemical evaluation of cartilage and may offer advantages in monitoring outcomes after cartilage repair surgery. Hypothesis: qMRI sequences will correlate with early pain and functional measures. Study Design: Systematic review; Level of evidence, 3...
April 2018: Orthopaedic Journal of Sports Medicine
https://www.readbyqxmd.com/read/29656880/fundamentals-of-functional-imaging-ii-emerging-mr-techniques-and-new-methods-of-analysis
#14
A Luna, T Martín Noguerol, L Alcalá Mata
Current multiparameter MRI protocols integrate structural, physiological, and metabolic information about cancer. Emerging techniques such as arterial spin-labeling (ASL), blood oxygen level dependent (BOLD), MR elastography, chemical exchange saturation transfer (CEST), and hyperpolarization provide new information and will likely be integrated into daily clinical practice in the near future. Furthermore, there is great interest in the study of tumor heterogeneity as a prognostic factor and in relation to resistance to treatment, and this interest is leading to the application of new methods of analysis of multiparametric protocols...
April 12, 2018: Radiología
https://www.readbyqxmd.com/read/29645309/hydrazo-cest-hydrazone-dependent-chemical-exchange-saturation-transfer-magnetic-resonance-imaging-contrast-agents
#15
Trina Dang, Mojmir Suchy, Yen Truong, Wendy Oakden, Wilfred Lam, Caitlin Lazurko, Glenn Facey, Greg Stanisz, Adam Shuhendler
The rapid formation of hydrazones under physiological conditions was exploited for the detection of aldehydes through chemical exchange saturation transfer magnetic resonance imaging (CEST-MRI). A metal-free, diamagnetic contrast agent derived from N-amino anthranilic acid was introduced, which selectively 'turned-on' upon hydrazone formation through an effect termed Hydrazo-CEST. While the hydrazine form of the probe produced no CEST-MRI signal enhancement, the formation of the aryl hydrazone resulted in >20% intensity decrease in the bulk water signal through the CEST effect, as measured by 300 MHz 1H NMR, 3T and 7T MRI...
April 12, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29626359/simultaneous-ph-sensitive-and-oxygen-sensitive-mri-of-human-gliomas-at-3-t-using-multi-echo-amine-proton-chemical-exchange-saturation-transfer-spin-and-gradient-echo-echo-planar-imaging-cest-sage-epi
#16
Robert J Harris, Jingwen Yao, Ararat Chakhoyan, Catalina Raymond, Kevin Leu, Linda M Liau, Phioanh L Nghiemphu, Albert Lai, Noriko Salamon, Whitney B Pope, Timothy F Cloughesy, Benjamin M Ellingson
PURPOSE: To introduce a new pH-sensitive and oxygen-sensitive MRI technique using amine proton CEST echo spin-and-gradient echo (SAGE) EPI (CEST-SAGE-EPI). METHODS: pH-weighting was obtained using CEST estimations of magnetization transfer ratio asymmetry (MTRasym ) at 3 ppm, and oxygen-weighting was obtained using R2' measurements. Glutamine concentration, pH, and relaxation rates were varied in phantoms to validate simulations and estimate relaxation rates. The values of MTRasym and R2' in normal-appearing white matter, T2 hyperintensity, contrast enhancement, and macroscopic necrosis were measured in 47 gliomas...
April 6, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29594656/glioblastoma-gbm-effects-on-quantitative-mri-of-contralateral-normal-appearing-white-matter
#17
Hatef Mehrabian, Wilfred W Lam, Sten Myrehaug, Arjun Sahgal, Greg J Stanisz
PURPOSE: The objective was to investigate (with quantitative MRI) whether the normal appearing white matter (NAWM) of glioblastoma (GBM) patients on the contralateral side (cNAWM) was different from NAWM of healthy controls. METHODS: Thirteen patients with newly diagnosed GBM and nine healthy age-matched controls were MRI-scanned with quantitative magnetization transfer (qMT), chemical exchange saturation transfer (CEST), and transverse relaxation time (T2 )-mapping...
March 28, 2018: Journal of Neuro-oncology
https://www.readbyqxmd.com/read/29573050/mri-for-solitary-pulmonary-nodule-and-mass-assessment-current-state-of-the-art
#18
Yoshiharu Ohno, Hans-Ulrich Kauczor, Hiroto Hatabu, Joon Beom Seo, Edwin J R van Beek
Since the clinical introduction of magnetic resonance imaging (MRI), the chest has been one of its most challenging applications, and many physicists and radiologists have tried since the 1980s to use MR for assessment of different lung diseases as well as mediastinal and pleural diseases. Since then, however, technical advances in sequencing, scanners, and coils, adaptation of parallel imaging techniques, utilization of contrast media, and development of postprocessing tools have been reported by many basic and clinical researchers...
March 23, 2018: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29545551/non-invasive-detection-of-adeno-associated-viral-gene-transfer-using-a-genetically-encoded-cest-mri-reporter-gene-in-the-murine-heart
#19
Shelby Meier, Assaf A Gilad, J Anthony Brandon, Chenghao Qian, Erhe Gao, Jose F Abisambra, Moriel Vandsburger
Research into gene therapy for heart failure has gained renewed interest as a result of improved safety and availability of adeno-associated viral vectors (AAV). While magnetic resonance imaging (MRI) is standard for functional assessment of gene therapy outcomes, quantitation of gene transfer/expression relies upon tissue biopsy, fluorescence or nuclear imaging. Imaging of gene expression through the use of genetically encoded chemical exchange saturation transfer (CEST)-MRI reporter genes could be combined with clinical cardiac MRI methods to comprehensively probe therapeutic gene expression and subsequent outcomes...
March 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29511438/multi-parameter-evaluation-of-lumbar-intervertebral-disc-degeneration-using-quantitative-magnetic-resonance-imaging-techniques
#20
Xuanqi Xiong, Zhengwei Zhou, Matteo Figini, Junjie Shangguan, Zhuoli Zhang, Wei Chen
Objective: To quantitatively evaluate lumbar disc degeneration with recently-developed quantitative magnetic resonance imaging (MRI) techniques. A series of MRI parameters, including T2*, T1rho relaxation time, apparent diffusion coefficient and gagCEST, were compared and correlated with the Pfirrmann semi-quantitative classification of lumbar intervertebral disc degeneration; the most accurate and relevant MRI parameters of lumbar disc degeneration were identified. Materials and Methods: Thirty-seven subjects (age range, 18-74 years) with non-specific low back pain (LBP) for more than 6 months were enrolled...
2018: American Journal of Translational Research
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