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Chemical exchange saturation transfer

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https://www.readbyqxmd.com/read/27911361/spin-saturation-transfer-difference-nmr-sstd-nmr-a-new-tool-to-obtain-kinetic-parameters-of-chemical-exchange-processes
#1
María Teresa Quirós, Colin Macdonald, Jesús Angulo, María Paz Muñoz
This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our group to study processes of mutual-site chemical exchange that are difficult to analyze by traditional methods. As the name suggests, this method combines the Spin Saturation Transfer method used for small molecules, with the Saturation Transfer Difference (STD) NMR method employed for the study of protein-ligand interactions, by measuring transient spin saturation transfer along increasing saturation times (build-up curves) in small organic and organometallic molecules undergoing chemical exchange...
November 12, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27898185/perfusion-has-no-effect-on-the-in-vivo-cest-effect-from-cr-crcest-in-skeletal-muscle
#2
Feliks Kogan, Randall B Stafford, Erin K Englund, Garry E Gold, Hari Hariharan, John A Detre, Ravinder Reddy
Creatine, a key component of muscle energy metabolism, exhibits a chemical exchange saturation transfer (CEST) effect between its amine group and bulk water, which has been exploited to spatially and temporally map creatine changes in skeletal muscle before and after exercise. In addition, exercise leads to an increase in muscle perfusion. In this work, we determined the effects of perfused blood on the CEST effects from creatine in skeletal muscle. Experiments were performed on healthy human subjects (n = 5) on a whole-body Siemens 7T magnetic resonance imaging (MRI) scanner with a 28-channel radiofrequency (RF) coil...
November 29, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27896628/clinical-translation-of-tumor-acidosis-measurements-with-acidocest-mri
#3
Kyle M Jones, Edward A Randtke, Eriko S Yoshimaru, Christine M Howison, Pavani Chalasani, Robert R Klein, Setsuko K Chambers, Phillip H Kuo, Mark D Pagel
PURPOSE: We optimized acido-chemical exchange saturation transfer (acidoCEST) magnetic resonance imaging (MRI), a method that measures extracellular pH (pHe), and translated this method to the radiology clinic to evaluate tumor acidosis. PROCEDURES: A CEST-FISP MRI protocol was used to image a flank SKOV3 tumor model. Bloch fitting modified to include the direct estimation of pH was developed to generate parametric maps of tumor pHe in the SKOV3 tumor model, a patient with high-grade invasive ductal carcinoma, and a patient with metastatic ovarian cancer...
November 28, 2016: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://www.readbyqxmd.com/read/27888530/perturbation-of-longitudinal-relaxation-rate-in-rotating-frame-plrf-analysis-for-quantification-of-chemical-exchange-saturation-transfer-signal-in-a-transient-state
#4
Yi Wang, Yaoyu Zhang, Xuna Zhao, Bing Wu, Jia-Hong Gao
PURPOSE: To develop a novel analytical method for quantification of chemical exchange saturation transfer (CEST) in the transient state. The proposed method aims to reduce the effects of non-chemical-exchange (non-CE) parameters on the CEST signal, emphasizing the effect of chemical exchange. METHODS: The difference in the longitudinal relaxation rate in the rotating frame ( ΔR1ρ) was calculated based on perturbation of the Z-value by R1ρ, and a saturation-pulse-amplitude-compensated exchange-dependent relaxation rate (SPACER) was determined with a high-exchange-rate approximation...
November 25, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27859838/aggregation-induced-changes-in-the-chemical-exchange-saturation-transfer-cest-signals-of-proteins
#5
Steffen Goerke, Katharina S Milde, Raul Bukowiecki, Patrick Kunz, Karel D Klika, Thomas Wiglenda, Axel Mogk, Erich E Wanker, Bernd Bukau, Mark E Ladd, Peter Bachert, Moritz Zaiss
Chemical exchange saturation transfer (CEST) is an MRI technique that allows mapping of biomolecules (small metabolites, proteins) with nearly the sensitivity of conventional water proton MRI. In living organisms, several tissue-specific CEST effects have been observed and successfully applied to diagnostic imaging. In these studies, particularly the signals of proteins showed a distinct correlation with pathological changes. However, as CEST effects depend on various properties that determine and affect the chemical exchange processes, the origins of the observed signal changes remain to be understood...
November 11, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27816001/diamagnetic-chemical-exchange-saturation-transfer-diacest-affords-magnetic-resonance-imaging-of-extracellular-matrix-hydrogel-implantation-in-a-rat-model-of-stroke
#6
Tao Jin, Francesca J Nicholls, William R Crum, Harmanvir Ghuman, Stephen F Badylak, Michel Modo
Extracellular matrix (ECM) is widely used as an inductive biological scaffold to repair soft tissue after injury by promoting functional site-appropriate remodeling of the implanted material. However, there is a lack of non-invasive analysis methods to monitor the remodeling characteristics of the ECM material after implantation and its biodegradation over time. We describe the use of diamagnetic chemical exchange saturation transfer (CEST) magnetic resonance imaging to monitor the distribution of an ECM hydrogel after intracerebral implantation into a stroke cavity...
October 29, 2016: Biomaterials
https://www.readbyqxmd.com/read/27812541/muscle-oxidative-phosphorylation-quantitation-using-creatine-chemical-exchange-saturation-transfer-crcest-mri-in-mitochondrial-disorders
#7
Catherine DeBrosse, Ravi Prakash Reddy Nanga, Neil Wilson, Kevin D'Aquilla, Mark Elliott, Hari Hariharan, Felicia Yan, Kristin Wade, Sara Nguyen, Diana Worsley, Chevonne Parris-Skeete, Elizabeth McCormick, Rui Xiao, Zuela Zolkipli Cunningham, Lauren Fishbein, Katherine L Nathanson, David R Lynch, Virginia A Stallings, Marc Yudkoff, Marni J Falk, Ravinder Reddy, Shana E McCormack
Systemic mitochondrial energy deficiency is implicated in the pathophysiology of many age-related human diseases. Currently available tools to estimate mitochondrial oxidative phosphorylation (OXPHOS) capacity in skeletal muscle in vivo lack high anatomic resolution. Muscle groups vary with respect to their contractile and metabolic properties. Therefore, muscle group-specific estimates of OXPHOS would be advantageous. To address this need, a noninvasive creatine chemical exchange saturation transfer (CrCEST) MRI technique has recently been developed, which provides a measure of free creatine...
November 3, 2016: JCI Insight
https://www.readbyqxmd.com/read/27805423/the-potential-of-multiparametric-mri-of-the-breast
#8
Katja Pinker, Thomas H Helbich, Elizabeth A Morris
Magnetic resonance imaging (MRI) is an essential tool in breast imaging, with multiple established indications. Dynamic contrast-enhanced MRI (DCE-MRI) is the backbone of any breast MRI protocol and has an excellent sensitivity and good specificity for breast cancer diagnosis. DCE-MRI provides high-resolution morphological information, as well as some functional information about neo-angiogenesis as a tumour-specific feature. To overcome limitations in specificity, several other functional MRI parameters have been investigated and the application of these combined parameters is defined as multiparametric MRI (mpMRI) of the breast...
November 2, 2016: British Journal of Radiology
https://www.readbyqxmd.com/read/27748713/cellular-and-molecular-imaging-using-chemical-exchange-saturation-transfer
#9
Michael T McMahon, Assaf A Gilad
Chemical exchange saturation transfer (CEST) is a powerful new tool well suited for molecular imaging. This technology enables the detection of low concentration probes through selective labeling of rapidly exchanging protons or other spins on the probes. In this review, we will highlight the unique features of CEST imaging technology and describe the different types of CEST agents that are suited for molecular imaging studies, including CEST theranostic agents, CEST reporter genes, and CEST environmental sensors...
October 2016: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/27747879/invited-commentary-mapping-the-alteration-in-glutamate-with-glucest-mri-in-a-mouse-model-of-dopamine-deficiency-an-editorial-highlight-for-mapping-the-alterations-in-glutamate-with-glucest-mri-in-a-mouse-model-of-dopamine-deficiency
#10
Paul Cumming, Jürgen Gallinat
Read the highlighted article 'Mapping the alterations in glutamate with GluCEST MRI in a mouse model of dopamine deficiency' on page 432.
November 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27742110/interrogating-metabolism-in-brain-cancer
#11
REVIEW
Travis C Salzillo, Jingzhe Hu, Linda Nguyen, Nicholas Whiting, Jaehyuk Lee, Joseph Weygand, Prasanta Dutta, Shivanand Pudakalakatti, Niki Zacharias Millward, Seth T Gammon, Frederick F Lang, Amy B Heimberger, Pratip K Bhattacharya
This article reviews existing and emerging techniques of interrogating metabolism in brain cancer from well-established proton magnetic resonance spectroscopy to the promising hyperpolarized metabolic imaging and chemical exchange saturation transfer and emerging techniques of imaging inflammation. Some of these techniques are at an early stage of development and clinical trials are in progress in patients to establish the clinical efficacy. It is likely that in vivo metabolomics and metabolic imaging is the next frontier in brain cancer diagnosis and assessing therapeutic efficacy; with the combined knowledge of genomics and proteomics a complete understanding of tumorigenesis in brain might be achieved...
November 2016: Magnetic Resonance Imaging Clinics of North America
https://www.readbyqxmd.com/read/27717216/simulation-phantom-validation-and-clinical-evaluation-of-fast-ph-weighted-molecular-imaging-using-amine-chemical-exchange-saturation-transfer-echo-planar-imaging-cest-epi-in-glioma-at-3%C3%A2-t
#12
Robert J Harris, Timothy F Cloughesy, Linda M Liau, Phioanh L Nghiemphu, Albert Lai, Whitney B Pope, Benjamin M Ellingson
Acidity within the extracellular milieu is a hallmark of cancer. There is a current need for fast, high spatial resolution pH imaging techniques for clinical evaluation of cancers, including gliomas. Chemical exchange saturation transfer (CEST) MRI targeting fast-exchanging amine protons can be used to obtain high-resolution pH-weighted images, but conventional CEST acquisition strategies are slow. There is also a need for more accurate MR simulations to better understand the effects of amine CEST pulse sequence parameters on pH-weighted image contrast...
November 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27711138/a-potential-magnetic-resonance-imaging-technique-based-on-chemical-exchange-saturation-transfer-for-in-vivo-%C3%AE-aminobutyric-acid-imaging
#13
Gen Yan, Tao Zhang, Zhuozhi Dai, Meizhi Yi, Yanlong Jia, Tingting Nie, Handi Zhang, Gang Xiao, Renhua Wu
PURPOSE: We developed a novel magnetic resonance imaging (MRI) technique based on chemical exchange saturation transfer (CEST) for GABA imaging and investigated the concentration-dependent CEST effect ofGABA in a rat model of brain tumor with blood-brain barrier (BBB) disruption. MATERIALS AND METHODS: All MRI studies were performed using a 7.0-T Agilent MRI scanner. Z-spectra for GABA were acquired at 7.0 T, 37°C, and a pH of 7.0 using varying B1 amplitudes. CEST images of phantoms with different concentrations of GABA solutions (pH, 7...
2016: PloS One
https://www.readbyqxmd.com/read/27709896/fast-tissue-characterization-with-quantitative-high-resolution-magic-angle-spinning-hrmas-cest-z-spectroscopy
#14
Iris Yuwen Zhou, Taylor L Fuss, Takahiro Igarashi, Weiping Jiang, Xin Zhou, Leo L Cheng, Phillip Zhe Sun
Chemical exchange saturation transfer (CEST) provides sensitive MR contrast for probing dilute compounds via exchangeable protons, serving as an emerging molecular imaging methodology. CEST Z-spectrum is often acquired by sweeping radiofrequency saturation around bulk water resonance, offset by offset, to detect CEST effects at characteristic chemical shift offsets, which requires prolonged acquisition time. Herein, combining high-resolution magic angle spinning (HRMAS) with concurrent application of gradient and RF saturation to achieve fast Z-spectral acquisition, we demonstrated the feasibility of fast quantitative HRMAS CEST Z-spectroscopy...
October 6, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27690156/chemical-exchange-saturation-transfer-for-predicting-response-to-stereotactic-radiosurgery-in-human-brain-metastasis
#15
Kimberly L Desmond, Hatef Mehrabian, Sofia Chavez, Arjun Sahgal, Hany Soliman, Radoslaw Rola, Greg J Stanisz
PURPOSE: The purpose of this work was to determine the predictive value of chemical exchange saturation transfer (CEST) metrics in brain metastases treated with stereotactic radiosurgery (SRS). METHODS: CEST spectra at a radiofrequency power of 0.52 µT were collected on a 3 Tesla (T) magnetic resonance imaging from 25 patients at three time points: pretreatment, 1 week, and 1 month post-treatment. Amide proton transfer-weighted images and maps of the amplitude and width of Lorentzian-shaped CEST peaks and the relaxation-compensated AREX metric were constructed at the offset frequencies of amide, amine, and relayed nuclear Overhauser effect (NOE) from aliphatic groups as well as the broad magnetization transfer effect...
September 30, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27686882/determination-of-an-optimally-sensitive-and-specific-chemical-exchange-saturation-transfer-mri-quantification-metric-in-relevant-biological-phantoms
#16
Kevin J Ray, James R Larkin, Yee K Tee, Alexandre A Khrapitchev, Gogulan Karunanithy, Michael Barber, Andrew J Baldwin, Michael A Chappell, Nicola R Sibson
The purpose of this study was to develop realistic phantom models of the intracellular environment of metastatic breast tumour and naïve brain, and using these models determine an analysis metric for quantification of CEST MRI data that is sensitive to only labile proton exchange rate and concentration. The ability of the optimal metric to quantify pH differences in the phantoms was also evaluated. Novel phantom models were produced, by adding perchloric acid extracts of either metastatic mouse breast carcinoma cells or healthy mouse brain to bovine serum albumin...
November 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27677899/coexistence-of-multiple-minor-states-of-fatty-acid-binding-protein-and-their-functional-relevance
#17
Binhan Yu, Daiwen Yang
Proteins are dynamic over a wide range of timescales, but determining the number of distinct dynamic processes and identifying functionally relevant dynamics are still challenging. Here we present the study on human intestinal fatty acid binding protein (hIFABP) using a novel analysis of (15)N relaxation dispersion (RD) and chemical shift saturation transfer (CEST) experiments. Through combined analysis of the two types of experiments, we found that hIFABP exists in a four-state equilibrium in which three minor states interconvert directly with the major state...
September 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27670140/quantitative-chemical-exchange-saturation-transfer-mri-of-intervertebral-disc-in-a-porcine-model
#18
Zhengwei Zhou, Maxim Bez, Wafa Tawackoli, Joseph Giaconi, Dmitriy Sheyn, Sandra de Mel, Marcel M Maya, Barry D Pressman, Zulma Gazit, Gadi Pelled, Dan Gazit, Debiao Li
PURPOSE: Previous studies have associated low pH in intervertebral discs (IVDs) with discogenic back pain. The purpose of this study was to determine whether quantitative CEST (qCEST) MRI can be used to detect pH changes in IVDs in vivo. METHODS: The exchange rate ksw between glycosaminoglycan (GAG) protons and water protons was determined from qCEST analysis. Its dependence on pH value was investigated in GAG phantoms with varying pH and concentrations. The relationship between ksw and pH was studied further in vivo in a porcine model on a 3T MR scanner and validated using a pH meter...
December 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27662404/is-there-any-difference-in-amide-and-noe-cest-effects-between-white-and-gray-matter-at-7t
#19
Vitaliy Khlebnikov, Jeroen C W Siero, Jannie Wijnen, Fredy Visser, Peter R Luijten, Dennis W J Klomp, Hans Hoogduin
Measurement of Chemical Exchange Saturation Transfer (CEST) is providing tissue physiology dependent contrast, e.g. by looking at Amide and NOE (Nuclear Overhauser Enhancement) effects. CEST is unique in providing quantitative metabolite information at high imaging resolution. However, direct comparison of Amide and NOE effects between different tissues may result in wrong conclusions on the metabolite concentration due to the additional contributors to the observed CEST contrast, such as water content (WC) and water T1 relaxation (T1w)...
November 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/27651313/in-vivo-imaging-of-tumor-metabolism-and-acidosis-by-combining-pet-and-mri-cest-ph-imaging
#20
Dario L Longo, Antonietta Bartoli, Lorena Consolino, Paola Bardini, Francesca Arena, Markus Schwaiger, Silvio Aime
The vast majority of cancers exhibit increased glucose uptake and glycolysis regardless of oxygen availability. This metabolic shift leads to an enhanced production of lactic acid that decreases extracellular pH (pHe), a hallmark of the tumor microenvironment. In this way, dysregulated tumor pHe and upregulated glucose metabolism are linked tightly and their relative assessment may be useful to gain understanding of the underlying biology. Here we investigated noninvasively the in vivo correlation between tumor (18)F-FDG uptake and extracellular pH values in a murine model of HER2(+) breast cancer...
September 20, 2016: Cancer Research
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