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Liu Y, Gauthier GC, Gendelman HE, Bade AN. Dual-Peak Lorentzian CEST MRI for antiretroviral drug brain distribution. NEUROIMMUNE PHARMACOLOGY AND THERAPEUTICS 2023; 2:63-69. [PMID: 37027345 PMCID: PMC10070014 DOI: 10.1515/nipt-2022-0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 08/24/2022] [Indexed: 11/15/2022]
Abstract
Objectives Spatial-temporal biodistribution of antiretroviral drugs (ARVs) can now be achieved using MRI by utilizing chemical exchange saturation transfer (CEST) contrasts. However, the presence of biomolecules in tissue limits the specificity of current CEST methods. To overcome this limitation, a Lorentzian line-shape fitting algorithm was developed that simultaneously fits CEST peaks of ARV protons on its Z-spectrum. Case presentation This algorithm was tested on the common first line ARV, lamivudine (3TC), that has two peaks resulting from amino (-NH2) and hydroxyl (-OH) protons in 3TC. The developed dual-peak Lorentzian function fitted these two peaks simultaneously, and used the ratio of -NH2 and -OH CEST contrasts as a constraint parameter to measure 3TC presence in brains of drug-treated mice. 3TC biodistribution calculated using the new algorithm was compared against actual drug levels measured using UPLC-MS/MS. In comparison to the method that employs the -NH2 CEST peak only, the dual-peak Lorentzian fitting algorithm showed stronger correlation with brain tissue 3TC levels, signifying estimation of actual drug levels. Conclusions We concluded that 3TC levels can be extracted from confounding CEST effects of tissue biomolecules resulting in improved specificity for drug mapping. This algorithm can be expanded to measure a variety of ARVs using CEST MRI.
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Affiliation(s)
- Yutong Liu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Radiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Gabriel C. Gauthier
- Department of Radiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Howard E. Gendelman
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Aditya N. Bade
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
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2
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Martinho RP, Jain MG, Frydman L. High-field ex vivo and in vivo two-dimensional nuclear magnetic resonance spectroscopy in murine brain: Resolving and exploring the molecular environment. NMR IN BIOMEDICINE 2023; 36:e4833. [PMID: 36114827 PMCID: PMC10077987 DOI: 10.1002/nbm.4833] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
The structural and chemical complexities within the brain pose a challenge that few noninvasive techniques can tackle with the dexterity of nuclear magnetic resonance (NMR) spectroscopy. Still, even with the advent of ultrahigh fields and of cryogenically cooled coils for in vivo research, the superposition of metabolic resonances arising from the brain remains a challenge. The present study explores the potential to tackle this milieu using a combination of two-dimensional (2D) NMR techniques, implemented on murine brains in vivo at 15.2 T and ex vivo at 14.1 T. While both experiments were affected by substantial inhomogeneous broadenings conveying distinct elongated lineshapes to the cross-peaks, the ability of increased fields to resolve off-diagonal resonances was clear. A comparison between the corresponding conventional and double quantum-filtered correlated spectroscopy traces enabled an improved assignment of in vivo resonances on the basis of more sensitive ex vivo 2D acquisitions, foremost on the basis of homonuclear cross-relaxation-driven correlations for peaks resonating downfield from water, and of heteronuclear correlations at natural abundance for the upfield protons. With the aid of such 2D correlations approximately 29 metabolites could be resolved and identified. This enhanced resolution was used to explore features related to the metabolites' diffusivities, their exposure to water, and their facility to undergo magnetization transfers to amide/amine/hydroxyl resonances. Cross-peaks from main murine brain biomolecules, including choline, creatine, γ-aminobutyric acid, N-acetyl aspartate, glutamine, and glutamate, showed enhancements in several of these various features, opening interesting vistas about metabolite compartmentalization as viewed by these 2D NMR experiments.
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Affiliation(s)
- Ricardo P. Martinho
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
| | - Mukul G. Jain
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
| | - Lucio Frydman
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
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3
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Martinho RP, Frydman L. Harnessing Water to Enhance Quadrupolar NMR Spectroscopy and Imaging. Chemistry 2022; 28:e202201490. [PMID: 36062375 PMCID: PMC9828088 DOI: 10.1002/chem.202201490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Indexed: 01/12/2023]
Abstract
17 O and 14 N are attractive targets for in vivo NMR spectroscopy and imaging, but low gyromagnetic ratios γ and fast spin relaxation complicate observations. This work explores indirect ways of detecting some of these sites with the help of proton-detected double resonance techniques. As standard coherence transfer methods are of limited use for such indirect detection, alternative routes for probing the quadrupolar spectra on 1 H were tested. These centered on modulating the broadening effects imparted onto protons adjacent to the low-γ species through J couplings through either continuous wave or spin-echo double-resonance decoupling/recoupling sequences. As in all cases, the changes imparted by these double-resonance strategies were small due to the fast relaxation undergone by the quadrupoles, the sensitivity of these approaches was amplified by transferring their effects onto the abundant water 1 H signal. These amplifications were mediated by the spontaneous exchanges that the labile 1 Hs bound to 17 O or 14 N undergo with the water protons. In experiments designed on the basis of double-resonance spin echoes, these enhancements were imparted by looping the transverse encodings together with multiple longitudinal storage periods, leading to decoupling-recoupling with exchange (D-REX) sequences. In experiments designed on the basis of continuous on/off quadrupolar decoupling, these solvent exchanges were incorporated into chemical-exchange saturation transfer schemes, leading to decoupling-recoupling with saturation transfer (D-REST) sequences. Both of these variants harnessed sizable proportions of the easily detectable water signals, in order to characterize the NMR spectra and/or to image with atomic-site specificity the 17 O and 14 N species.
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Affiliation(s)
- Ricardo P. Martinho
- Department of Chemical and Biological PhysicsWeizmann Institute of Science7610001RehovotIsrael
| | - Lucio Frydman
- Department of Chemical and Biological PhysicsWeizmann Institute of Science7610001RehovotIsrael
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4
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Wu ST, Chen PC, Tseng YH, Chen TH, Wang YJ, Tsai ZL, Lin EC. Assessment of cellular responses in three-dimensional cell cultures through chemical exchange saturation transfer and 1 H MRS. NMR IN BIOMEDICINE 2022; 35:e4757. [PMID: 35510307 DOI: 10.1002/nbm.4757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 04/21/2022] [Accepted: 05/02/2022] [Indexed: 06/14/2023]
Abstract
Metabolic responses to physiological changes have been detected using chemical exchange saturation transfer (CEST) imaging in clinical settings. Similarly to other MRI techniques, the CEST technique was based originally on phantoms from buffer solutions and was then further developed through animal experiments. However, CEST imaging can capture certain dynamics of metabolism that solution phantoms cannot model. Cell culture phantoms can fill the gap between buffer phantoms and animal models. In this study, we used 1 H NMR and CEST in a B0 field of 9.4 T to investigate HEK293T cells from two-dimensional (2D) cultures, three-dimensional (3D) cultures, and 3D cultures seeded with cell spheroids. Two CEST dips were observed: the magnitude of the amine dip at 2.8 ppm increased during the incubation period, whereas the hydroxyl dip at 1.2 ppm remained approximately the same or modestly increased. We also observed a CEST dip at 2.8 ppm from the 2D culture responding dramatically to doxorubicin treatment. By cross-validating with pH values and the concentrations of amine and hydroxyl protons extracted through 1 H NMR, we observed that they did not correspond to an increase in the amine pool. We believe that the denaturation or degradation of proteins from the fetal bovine serum increased the size of the amine pool. Although 3D culture conditions can be further improved, our study suggests that 3D cultures have the potential to bridge studies of solution phantoms and those on animals.
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Affiliation(s)
- Ssu-Ting Wu
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Pin-Chen Chen
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Yu-Hsien Tseng
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Ting-Hao Chen
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Yi-Jiun Wang
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Zong-Lin Tsai
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
| | - Eugene C Lin
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan
- Center for Nano Bio-detection, National Chung Cheng University, Chiayi, Taiwan
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5
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Wermter FC, Bock C, Dreher W. Characterization of amine proton exchange for analyzing the specificity and intensity of the CEST effect: from humans to fish. NMR IN BIOMEDICINE 2022; 35:e4622. [PMID: 34605080 DOI: 10.1002/nbm.4622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Chemical exchange saturation transfer (CEST) at about 2.8 ppm downfield from water is characterized besides other compounds by exchanging amine protons of relatively high concentration amino acids and is determined by several physiological (pH, T) and experimental (B0 , B1 , tsat ) parameters. Although the weighting of the CEST effect observed in vivo can be attributed mainly to one compound depending on the organism and organ, there are still several other amino acids, proteins and molecules that also contribute. These contributions in turn exhibit dependences and thus can lead to possible misinterpretation of the measured changes in the CEST effect. With this in mind, this work aimed to determine the exchange rates of six important amino acids as a function of pH and temperature, and thus to create multi-pool models that allow the accurate analysis of the CEST effect concerning different physiological and experimental parameters for a wide variety of organisms. The results show that small changes in the above parameters have a significant impact on the CEST effect at about 2.8 ppm for the chosen organisms, i.e. the human brain (37 °C) and the brain of polar cod (1.5 °C), furthermore, the specificity of the CEST effect observed in vivo can be significantly affected. Based on the exchange rates ksw (pH, T) determined for six metabolites in this study, it is possible to optimize the intensity and the specificity for the CEST effect of amino acids at about 2.8 ppm for different organisms with their specific physiological characteristics. By adjusting experimental parameters accordingly, this optimization will help to avoid possible misinterpretations of CEST measurements. Furthermore, the multi-pool models can be utilized to further optimize the saturation.
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Affiliation(s)
- Felizitas C Wermter
- Department of Chemistry, in-vivo-MR group, University Bremen, Bremen, Germany
| | - Christian Bock
- Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Wolfgang Dreher
- Department of Chemistry, in-vivo-MR group, University Bremen, Bremen, Germany
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6
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Saito S. [5. Advanced Imaging Technology-T1rho-CEST Imaging]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:95-100. [PMID: 35046227 DOI: 10.6009/jjrt.780111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shigeyoshi Saito
- Laboratory of Advanced Imaging Technology, Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine.,Department of Advanced Medical Technology, National Cardiovascular and Cerebral Research Center
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7
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Saturation transfer MRI is sensitive to neurochemical changes in the rat brain due to chronic unpredictable mild stress. Sci Rep 2021; 11:19040. [PMID: 34561488 PMCID: PMC8463565 DOI: 10.1038/s41598-021-97991-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/31/2021] [Indexed: 02/08/2023] Open
Abstract
Chemical exchange saturation transfer (CEST) MRI was performed for the evaluation of cerebral metabolic changes in a rat model of depressive-like disease induced by chronic unpredictable mild stress (CUMS). CEST Z-spectra were acquired on a 7 T MRI with two saturation B1 amplitudes (0.5 and 0.75 µT) to measure the magnetization transfer ratio (MTR), CEST and relayed nuclear Overhauser effect (rNOE). Cerebral cortex and hippocampus were examined in two groups of animals: healthy control (n = 10) and stressed (n = 14), the latter of which was exposed to eight weeks of the CUMS protocol. The stressed group Z-spectrum parameters, primarily MTRs, were significantly lower than in controls, at all selected frequency offsets (3.5, 3.0, 2.0, - 3.2, - 3.6 ppm) in the cortex (the largest difference of ~ 3.5% at - 3.6 ppm, p = 0.0005) and the hippocampus (MTRs measured with a B1 = 0.5 µT). The hippocampal rNOE contributions decreased significantly in the stressed brains. Glutamate concentration (assessed using ELISA) and MTR at 3 ppm correlated positively in both brain regions. GABA concentration also correlated positively with CEST contributions in both cerebral areas, while such correlation with MTR was positive in hippocampus, and nonsignificant in cortex. Results indicate that CEST is sensitive to neurometabolic changes following chronic stress exposure.
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8
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Schmitz-Abecassis B, Vinogradov E, Wijnen JP, van Harten T, Wiegers EC, Hoogduin H, van Osch MJP, Ercan E. The use of variable delay multipulse chemical exchange saturation transfer for separately assessing different CEST pools in the human brain at 7T. Magn Reson Med 2021; 87:872-883. [PMID: 34520077 PMCID: PMC9290048 DOI: 10.1002/mrm.29005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE Current challenges of in vivo CEST imaging include overlapping signals from different pools. The overlap arises from closely resonating pools and/or the broad magnetization transfer contrast (MTC) from macromolecules. This study aimed to evaluate the feasibility of variable delay multipulse (VDMP) CEST to separately assess solute pools with different chemical exchange rates in the human brain in vivo, while mitigating the MTC. METHODS VDMP saturation buildup curves were simulated for amines, amides, and relayed nuclear Overhauser effect. VDMP data were acquired from glutamate and bovine serum albumin phantoms, and from six healthy volunteers at 7T. For the in vivo data, MTC removal was performed via a three-pool Lorentzian fitting. Different B1 amplitudes and mixing times were used to evaluate CEST pools with different exchange rates. RESULTS The results show the importance of removing MTC when applying VDMP in vivo and the influence of B1 for distinguishing different pools. Finally, the optimal B1 and mixing times to effectively saturate slow- and fast-exchanging components are also reported. Slow-exchanging amides and rNOE components could be distinguished when using B1 = 1 μT and tmix = 10 ms and 40 ms, respectively. Fast-exchanging components reached the highest saturation when using a B1 = 2.8 μT and tmix = 0 ms. CONCLUSION VDMP is a powerful CEST-editing tool, exploiting chemical exchange-rate differences. After MTC removal, it allows separate assessment of slow- and fast-exchanging solute pools in in vivo human brain.
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Affiliation(s)
- Bárbara Schmitz-Abecassis
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Elena Vinogradov
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jannie P Wijnen
- Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Thijs van Harten
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Evita C Wiegers
- Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hans Hoogduin
- Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Matthias J P van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ece Ercan
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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9
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Oglesby RT, Lam WW, Stanisz GJ. A strategy to prevent a temperature-induced MRI artifact in warm liquid phantoms due to convection currents. NMR IN BIOMEDICINE 2021; 34:e4494. [PMID: 33586271 DOI: 10.1002/nbm.4494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/16/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
MRI phantom studies often fail to mimic the temperature of the human body, which can negatively impact accuracy. An artifact induced by increasing temperature in liquid phantoms was observed, presenting a significant challenge to temperature-controlled experiments. In this study we characterize and provide a solution to eliminate this temperature-induced MRI artifact. Low concentration (0.5-2.5 mM) agar phantoms were prepared. Utilizing a temperature-controlled phantom holder, T1 - and T2 -weighted structural images were acquired at 7 T along with quantitative B0 , B1 , T1 , T2 and ADC maps at both 25 and 37°C. Additionally, computer simulations were conducted to demonstrate the fluid flow and thermal flux patterns in water to provide an insight into the origins of the artifact. Evidence from computer simulation and quantitative MRI strongly suggest the artifact was caused by heat transfer in the form of natural convection leading to structured patterns of signal loss in MR images. The artifact was present up to agar concentrations of 1.5 mM (T1 = 3068 ± 16 ms, T2 = 1052 ± 20 ms, ADC = 2.29 ± 0.36 × 10-3 mm2 /s at 25°C; T1 = 3928 ± 44 ms, T2 = 1122 ± 24 ms, ADC = 2.64 ± 0.49 × 10-3 mm2 /s at 37°C), above which point increased sample viscosity no longer allows for convection currents, thereby eliminating the artifact. The methodology described in this work simplifies quantitative MR acquisition of liquid phantoms at physiological temperature by suppressing convection currents with relatively small changes to intrinsic MR parameters (T1 increased by 1.4% and T2 decreased by 17% for 1.5 mM agar at 25°C).
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Affiliation(s)
- Ryan T Oglesby
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
- Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Wilfred W Lam
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Greg J Stanisz
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
- Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Neurosurgery and Paediatric Neurosurgery, Medical University of Lublin, Lublin, Poland
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10
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Sydnor VJ, Roalf DR. A meta-analysis of ultra-high field glutamate, glutamine, GABA and glutathione 1HMRS in psychosis: Implications for studies of psychosis risk. Schizophr Res 2020; 226:61-69. [PMID: 32723493 PMCID: PMC7750272 DOI: 10.1016/j.schres.2020.06.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022]
Abstract
Ultra-high field proton magnetic resonance spectroscopy (1HMRS) offers a unique opportunity to measure the concentration of neurometabolites implicated in psychosis (PSY). The extant 7 T 1HMRS literature measuring glutamate-associated neurometabolites in the brain in PSY in vivo is small, but a comprehensive, quantitative summary of these data can offer insight and guidance to this emerging field. This meta-analysis examines proton spectroscopy (1HMRS) measures of glutamate (Glu), glutamine (Gln), glutamate+glutamine (Glx), gamma aminobutyric acid (GABA), and glutathione (GSH) across 255 individuals with PSY (121 first episode) and 293 healthy comparison participants (HC). While all five neurometabolites were lower in PSY as compared to HC, only Glu (Cohen's d = -0.18) and GSH (Cohen's d = -0.21) concentrations were significantly lower in PSY, whereas concentrations of Gln, Glx, and GABA did not significantly differ between groups. Notably, 1HMRS methodological choices and sample demographic characteristics did not impact study-specific effect sizes for PSY-related Glu or GSH differences. This review thus provides further evidence of neurometabolite dysfunction in first episode and chronic PSY, and thereby suggests that Glu and GSH abnormalities may additionally play a role in more incipient stages of the disorder: in clinical high risk stages. Additional 7 T neurochemical imaging studies in larger, longitudinal, and unmedicated samples and in youth at risk for developing psychosis are needed. Such studies will be critical for elucidating the neurodevelopmental and clinical time course of PSY-related neurometabolite alterations, and for assessing the potential for implicated metabolites to serve as druggable targets for decreasing PSY risk.
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Affiliation(s)
- Valerie J Sydnor
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - David R Roalf
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, United States of America; Lifespan Brain Institute at the Children's Hospital of Philadelphia & the University of Pennsylvania, Philadelphia, PA 19104, United States of America.
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11
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Guo C, Wu J, Rosenberg JT, Roussel T, Cai S, Cai C. Fast chemical exchange saturation transfer imaging based on PROPELLER acquisition and deep neural network reconstruction. Magn Reson Med 2020; 84:3192-3205. [PMID: 32602965 DOI: 10.1002/mrm.28376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To develop a method for fast chemical exchange saturation transfer (CEST) imaging. METHODS The periodically rotated overlapping parallel lines enhanced reconstruction (PROPELLER) sampling scheme was introduced to shorten the acquisition time. Deep neural network was employed to reconstruct CEST contrast images. Numerical simulation and experiments on a creatine phantom, hen egg, and in vivo tumor rat brain were performed to test the feasibility of this method. RESULTS The results from numerical simulation and experiments show that there is no significant difference between reference images and CEST-PROPELLER reconstructed images under an acceleration factor of 8. CONCLUSION Although the deep neural network is trained entirely on synthesized data, it works well on reconstructing experimental data. The proof of concept study demonstrates that the combination of the PROPELLER sampling scheme and the deep neural network enables considerable acceleration of saturated image acquisition and may find applications in CEST MRI.
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Affiliation(s)
- Chenlu Guo
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Jian Wu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Jens T Rosenberg
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Tangi Roussel
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Congbo Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
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12
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Joo CG, Yang SH, Choi Y, Son HY, Kim DH, Huh YM. L-glutamine as a T 2 exchange contrast agent. Magn Reson Med 2020; 84:2055-2062. [PMID: 32406063 DOI: 10.1002/mrm.28305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE The potential of L-glutamine as a T2 exchange contrast agent in MRI was investigated. METHODS The T2 relaxation rate of L-glutamine solutions prepared in various concentrations was measured at 9.4 T. A series of T2 -weighted images in a mouse cancer model was acquired with an L-glutamine solution infusion. RESULTS The T2 relaxivity caused by the exchange (R2ex ) at 37°C was 0.069 s-1 mM-1 and 0.102 s-1 mM-1 for glutamine and glutamate solutions at pH = 7.2, respectively. The R2ex of glutamine at pH = 6.1-6.7 was in the 0.097-0.1 s-1 mM-1 range. No significant dependence of T1 on the concentration of glutamine was observed. The dynamic measurement of T2 -weighted images in vivo showed that the glutamine uptake was primarily observed at the localized part of the tumor CONCLUSION: L-glutamine can be used as a T2 exchange contrast agent and images of glutamine uptake in vivo can be acquired.
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Affiliation(s)
- Chan Gyu Joo
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Seung-Hyun Yang
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Yuna Choi
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Hye-Young Son
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea.,Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong-Hyun Kim
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Yong-Min Huh
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea.,YUHS-KRIBB Medical Convergence Research Institute, Yonsei University, Seoul, Korea
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13
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Smith AK, Ray KJ, Larkin JR, Craig M, Smith SA, Chappell MA. Does the magnetization transfer effect bias chemical exchange saturation transfer effects? Quantifying chemical exchange saturation transfer in the presence of magnetization transfer. Magn Reson Med 2020; 84:1359-1375. [PMID: 32072677 PMCID: PMC7317383 DOI: 10.1002/mrm.28212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 12/13/2022]
Abstract
Purpose Chemical exchange saturation transfer (CEST) is an MRI technique sensitive to the presence of low‐concentration solute protons exchanging with water. However, magnetization transfer (MT) effects also arise when large semisolid molecules interact with water, which biases CEST parameter estimates if quantitative models do not account for macromolecular effects. This study establishes under what conditions this bias is significant and demonstrates how using an appropriate model provides more accurate quantitative CEST measurements. Methods CEST and MT data were acquired in phantoms containing bovine serum albumin and agarose. Several quantitative CEST and MT models were used with the phantom data to demonstrate how underfitting can influence estimates of the CEST effect. CEST and MT data were acquired in healthy volunteers, and a two‐pool model was fit in vivo and in vitro, whereas removing increasing amounts of CEST data to show biases in the CEST analysis also corrupts MT parameter estimates. Results When all significant CEST/MT effects were included, the derived parameter estimates for each CEST/MT pool significantly correlated (P < .05) with bovine serum albumin/agarose concentration; minimal or negative correlations were found with underfitted data. Additionally, a bootstrap analysis demonstrated that significant biases occur in MT parameter estimates (P < .001) when unmodeled CEST data are included in the analysis. Conclusions These results indicate that current practices of simultaneously fitting both CEST and MT effects in model‐based analyses can lead to significant bias in all parameter estimates unless a sufficiently detailed model is utilized. Therefore, care must be taken when quantifying CEST and MT effects in vivo by properly modeling data to minimize these biases.
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Affiliation(s)
- Alex K Smith
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Kevin J Ray
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - James R Larkin
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Martin Craig
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michael A Chappell
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom.,Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
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14
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Liu T, Chen Y, Thomas AM, Song X. CEST MRI with distribution-based analysis for assessment of early stage disease activity in a mouse model of multiple sclerosis: An initial study. NMR IN BIOMEDICINE 2019; 32:e4139. [PMID: 31342587 DOI: 10.1002/nbm.4139] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 06/10/2023]
Abstract
Imaging biomarkers that can detect pathological changes at an early stage of multiple sclerosis (MS) may allow earlier therapeutic intervention with an improved outcome. Using a mouse model of MS, termed as experimental autoimmune encephalomyelitis (EAE), we performed chemical exchange saturation transfer (CEST) MRI at a very early stage before symptom onset (6 days post-induction) for assessment of changes in tissues that appear "normal" with conventional MRI. The collected CEST Z-spectra signals (Ssat /S0 ) were analyzed using a histogram-guided method to determine the contributions from various offset frequencies. Histogram analysis showed that EAE mice exhibit a more heterogeneous distribution with lower peak heights in the hindbrain compared with naïve mice at saturation offsets of 1 and 2 ppm. At these two offsets, both the mean Ssat /S0 and the mean MTRasym values in the cerebellum and brain stem are significantly different between EAE and naïve mice (P < 0.05). Immunofluorescent staining validated the presence of neuroinflammation, with IBA1-positive cells detected throughout the hindbrain including the cerebellum and brain stem. Follow-up MRI at the symptom onset (score = 1.5-2.5, 13 days post-induction) confirmed gadolinium-enhanced periventricular lesions. CEST Z-spectra signals also changed by this time. The proposed three-level histogram-oriented analysis is simple to execute and robust for detecting subtle changes in Z-spectra signals, which does not require a priori knowledge of damage locations or contributing offset components. CEST MRI signals at 1 and 2 ppm were sensitive to the subtle pathological changes at an early stage in EAE mice, and have potential as novel imaging biomarkers complementary to functional and physiological MRI measures.
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Affiliation(s)
- Tao Liu
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Dept. of Neurology, Hainan General Hospital, Haikou, Hainan, China
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yanrong Chen
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Dept. of Information Sciences and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Aline M Thomas
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Xiaolei Song
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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15
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Saito S, Tanoue M, Ohki A, Takahashi Y. [19. Application of Chemical Exchange Saturation Transfer Imaging Using Ultra-high Filed MRI]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2019; 75:1194-1199. [PMID: 31631114 DOI: 10.6009/jjrt.2019_jsrt_75.10.1194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shigeyoshi Saito
- Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine.,Department of Biomedical Imaging, National Cardiovascular and Cerebral Research Center
| | - Minori Tanoue
- Department of Clinical Radiology Service, Kyoto University Hospital
| | - Akiko Ohki
- Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine.,Department of Biomedical Imaging, National Cardiovascular and Cerebral Research Center
| | - Yusuke Takahashi
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
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16
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Sonkar K, Ayyappan V, Tressler CM, Adelaja O, Cai R, Cheng M, Glunde K. Focus on the glycerophosphocholine pathway in choline phospholipid metabolism of cancer. NMR IN BIOMEDICINE 2019; 32:e4112. [PMID: 31184789 PMCID: PMC6803034 DOI: 10.1002/nbm.4112] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/16/2019] [Accepted: 04/20/2019] [Indexed: 05/02/2023]
Abstract
Activated choline metabolism is a hallmark of carcinogenesis and tumor progression, which leads to elevated levels of phosphocholine and glycerophosphocholine in all types of cancer tested so far. Magnetic resonance spectroscopy applications have played a key role in detecting these elevated choline phospholipid metabolites. To date, the majority of cancer-related studies have focused on phosphocholine and the Kennedy pathway, which constitutes the biosynthesis pathway for membrane phosphatidylcholine. Fewer and more recent studies have reported on the importance of glycerophosphocholine in cancer. In this review article, we summarize the recent literature on glycerophosphocholine metabolism with respect to its cancer biology and its detection by magnetic resonance spectroscopy applications.
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Affiliation(s)
- Kanchan Sonkar
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vinay Ayyappan
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Caitlin M. Tressler
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Oluwatobi Adelaja
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ruoqing Cai
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Menglin Cheng
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kristine Glunde
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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17
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Stabinska J, Neudecker P, Ljimani A, Wittsack H, Lanzman RS, Müller‐Lutz A. Proton exchange in aqueous urea solutions measured by water‐exchange (WEX) NMR spectroscopy and chemical exchange saturation transfer (CEST) imaging in vitro. Magn Reson Med 2019; 82:935-947. [DOI: 10.1002/mrm.27778] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 03/06/2019] [Accepted: 03/28/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Julia Stabinska
- Department of Diagnostic and Interventional Radiology, Medical Faculty Heinrich Heine University Düsseldorf Dusseldorf Germany
| | - Philipp Neudecker
- Institute of Physical Biology Heinrich Heine University Düsseldorf Dusseldorf Germany
- Institute of Complex Systems: Structural Biochemistry (ICS‐6), Forschungszentrum Jülich Julich Germany
| | - Alexandra Ljimani
- Department of Diagnostic and Interventional Radiology, Medical Faculty Heinrich Heine University Düsseldorf Dusseldorf Germany
| | - Hans‐Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty Heinrich Heine University Düsseldorf Dusseldorf Germany
| | - Rotem Shlomo Lanzman
- Department of Diagnostic and Interventional Radiology, Medical Faculty Heinrich Heine University Düsseldorf Dusseldorf Germany
| | - Anja Müller‐Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty Heinrich Heine University Düsseldorf Dusseldorf Germany
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18
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Chemical exchange saturation transfer (CEST) as a new method of signal obtainment in magnetic resonance molecular imaging in clinical and research practice. Pol J Radiol 2019; 84:e147-e152. [PMID: 31019609 PMCID: PMC6479148 DOI: 10.5114/pjr.2019.84242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 02/14/2019] [Indexed: 01/04/2023] Open
Abstract
The work describes the physical basis of the chemical exchange saturation transfer (CEST) technique; it presents the beginnings of the implementation of the method and its possible applications. The principles of correct data acquisition and possible solutions used during the design of the CEST sequence are shown. The main problems related to data analysis are indicated, and an example Z-spectrum from in vivo study of the rat brain is introduced. Furthermore, the parameters related to spectrum analyses such as magnetisation transfer asymmetry (MTRasym) and amide proton transfer asymmetry (APTasym) are presented. In the following part, different types of the CEST method often mentioned in the literature are discussed. Subsequently, the possible applications of the CEST method in both clinical and experimental practice are described.
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19
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Zöllner HJ, Butz M, Jördens M, Füllenbach ND, Häussinger D, Schmitt B, Wittsack HJ, Schnitzler A. Chemical exchange saturation transfer imaging in hepatic encephalopathy. NEUROIMAGE-CLINICAL 2019; 22:101743. [PMID: 30856541 PMCID: PMC6411782 DOI: 10.1016/j.nicl.2019.101743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/04/2019] [Accepted: 03/02/2019] [Indexed: 01/08/2023]
Abstract
Hepatic encephalopathy (HE) is a common complication in liver cirrhosis and associated with an invasion of ammonia into the brain through the blood-brain barrier. Resulting higher ammonia concentrations in the brain are suggested to lead to a dose-dependent gradual increase of HE severity and an associated impairment of brain function. Amide proton transfer-weighted (APTw) chemical exchange saturation transfer (CEST) imaging has been found to be sensitive to ammonia concentration. The aim of this work was to study APTw CEST imaging in patients with HE and to investigate the relationship between disease severity, critical flicker frequency (CFF), psychometric test scores, blood ammonia, and APTw signals in different brain regions. Whole-brain APTw CEST images were acquired in 34 participants (14 controls, 20 patients (10 minimal HE, 10 manifest HE)) on a 3 T clinical MRI system accompanied by T1 mapping and structural images. T1 normalized magnetization transfer ratio asymmetry analysis was performed around 3 ppm after B0 and B1 correction to create APTw images. All APTw images were spatially normalized into a cohort space to allow direct comparison. APTw images in 6 brain regions (cerebellum, occipital cortex, putamen, thalamus, caudate, white matter) were tested for group differences as well as the link to CFF, psychometric test scores, and blood ammonia. A decrease in APTw intensities was found in the cerebellum and the occipital cortex of manifest HE patients. In addition, APTw intensities in the cerebellum correlated positively with several psychometric scores, such as the fine motor performance scores MLS1 for hand steadiness / tremor (r = 0.466; p = .044) and WRT2 for motor reaction time (r = 0.523; p = .022). Moreover, a negative correlation between APTw intensities and blood ammonia was found for the cerebellum (r = −0.615; p = .007) and the occipital cortex (r = −0.478; p = .045). An increase of APTw intensities was observed in the putamen of patients with minimal HE and correlated negatively with the CFF (r = −0.423; p = .013). Our findings demonstrate that HE is associated with regional differential alterations in APTw signals. These variations are most likely a consequence of hyperammonemia or hepatocerebral degeneration processes, and develop in parallel with disease severity. Ammonia is suggested to play a key role in the emergence of HE. Increase of ammonia in HE patients might be studied with APTw CEST. HE leads to regionally decreasing APTw CEST signal. APTw CEST correlates with blood ammonia levels and psychometric test scores. APTw CEST is possibly linked to hyperammonemia or hepatocerebral degeneration.
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Affiliation(s)
- Helge Jörn Zöllner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany; Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany.
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Markus Jördens
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Nur-Deniz Füllenbach
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Benjamin Schmitt
- Siemens Ltd. Australia, Healthcare Sector, 160 Herring Road, Macquarie Park, NSW 2113,Australia
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
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20
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Yanez Lopez M, Pardon MC, Baiker K, Prior M, Yuchun D, Agostini A, Bai L, Auer DP, Faas HM. Myoinositol CEST signal in animals with increased Iba-1 levels in response to an inflammatory challenge-Preliminary findings. PLoS One 2019; 14:e0212002. [PMID: 30789943 PMCID: PMC6383890 DOI: 10.1371/journal.pone.0212002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/08/2018] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation plays an important role in the pathogenesis of a range of brain disorders. Non-invasive imaging of neuroinflammation is critical to help improve our understanding of the underlying disease mechanisms, monitor therapies and guide drug development. Generally, MRI lacks specificity to molecular imaging biomarkers, but molecular MR imaging based on chemical exchange saturation transfer (CEST) can potentially detect changes of myoinositol, a putative glial marker that may index neuroinflammation. In this pilot study we aimed to investigate, through validation with immunohistochemistry and in vivo magnetic resonance spectroscopy (MRS), whether CEST imaging can reflect the microglial response to a mild inflammatory challenge with lipopolysaccharide (LPS), in the APPSwe/ PS1 mouse model of Alzheimer’s disease and wild type controls. The response to the immune challenge was variable and did not align with genotype. Animals with a strong response to LPS (Iba1+, n = 6) showed an increase in CEST contrast compared with those who did not (Iba1-, n = 6). Changes of myoinositol levels after LPS were not significant. We discuss the difficulties of this mild inflammatory model, the role of myoinositol as a glial biomarker, and the technical challenges of CEST imaging at 0.6ppm.
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Affiliation(s)
- Maria Yanez Lopez
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | | | - Kerstin Baiker
- School of Veterinary Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Malcolm Prior
- Medical Imaging Unit, University of Nottingham, Nottingham, United Kingdom
| | - Ding Yuchun
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alessandra Agostini
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Li Bai
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Dorothee P. Auer
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | - Henryk M. Faas
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
- * E-mail:
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21
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Khlebnikov V, van der Kemp WJM, Hoogduin H, Klomp DWJ, Prompers JJ. Analysis of chemical exchange saturation transfer contributions from brain metabolites to the Z-spectra at various field strengths and pH. Sci Rep 2019; 9:1089. [PMID: 30705355 PMCID: PMC6355971 DOI: 10.1038/s41598-018-37295-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 11/19/2018] [Indexed: 11/18/2022] Open
Abstract
Chemical exchange saturation transfer (CEST) exploits the chemical exchange of labile protons of an endogenous or exogenous compound with water to image the former indirectly through the water signal. Z-spectra of the brain have traditionally been analyzed for two most common saturation phenomena: downfield amide proton transfer (APT) and upfield nuclear Overhauser enhancement (NOE). However, a great body of brain metabolites, many of interest in neurology and oncology, contributes to the downfield saturation in Z-spectra. The extraction of these “hidden” metabolites from Z-spectra requires careful design of CEST sequences and data processing models, which is only possible by first obtaining CEST signatures of the brain metabolites possessing labile protons. In this work, we measured exchange rates of all major-for-CEST brain metabolites in the physiological pH range at 37 °C. Analysis of their contributions to Z-spectra revealed that regardless of the main magnetic field strength and pH, five main contributors, i.e. myo-inositol, creatine, phosphocreatine, glutamate, and mobile (poly)peptides, account for ca. 90% of downfield CEST effect. The fundamental CEST parameters presented in this study can be exploited in the design of novel CEST sequences and Z-spectra processing models, which will enable simultaneous and quantitative CEST imaging of multiple metabolites: multicolor CEST.
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Affiliation(s)
- Vitaliy Khlebnikov
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Wybe J M van der Kemp
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hans Hoogduin
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Department of Radiology, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
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22
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Han Z, Liu G. Sugar-based biopolymers as novel imaging agents for molecular magnetic resonance imaging. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2019; 11:e1551. [PMID: 30666829 DOI: 10.1002/wnan.1551] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/21/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022]
Abstract
Sugar-based biopolymers have been recognized as attractive materials to develop macromolecule- and nanoparticle-based cancer imaging and therapy. However, traditional biopolymer-based imaging approaches rely on the use of synthetic or isotopic labeling, and because of it, clinical translation often is hindered. Recently, a novel magnetic resonance imaging (MRI) technology, chemical exchange saturation transfer (CEST), has emerged, which allows the exploitation of sugar-based biopolymers as MRI agents by their hydroxyl protons-rich nature. In the study, we reviewed recent studies on the topic of CEST MRI detection of sugar-based biopolymers. The CEST MRI property of each biopolymer was briefly introduced, followed by the pre-clinical and clinical applications. The findings of these preliminary studies imply the enormous potential of CEST detectable sugar-based biopolymers in developing highly sensitive and translatable molecular imaging agents and constructing image-guided biopolymer-based drug delivery systems. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Emerging Technologies.
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Affiliation(s)
- Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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23
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Wermter FC, Maus B, Pörtner HO, Dreher W, Bock C. CO 2 induced pH i changes in the brain of polar fish: a TauCEST application. NMR IN BIOMEDICINE 2018; 31:e3955. [PMID: 29932479 DOI: 10.1002/nbm.3955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
Chemical exchange saturation transfer (CEST) from taurine to water (TauCEST) can be used for in vivo mapping of taurine concentrations as well as for measurements of relative changes in intracellular pH (pHi ) at temperatures below 37°C. Therefore, TauCEST offers the opportunity to investigate acid-base regulation and neurological disturbances of ectothermic animals living at low temperatures, and in particular to study the impact of ocean acidification (OA) on neurophysiological changes of fish. Here, we report the first in vivo application of TauCEST imaging. Thus, the study aimed to investigate the TauCEST effect in a broad range of temperatures (1-37°C) and pH (5.5-8.0), motivated by the high taurine concentration measured in the brains of polar fish. The in vitro data show that the TauCEST effect is especially detectable in the low temperature range and strictly monotonic for the relevant pH range (6.8-7.5). To investigate the specificity of TauCEST imaging for the brain of polar cod (Boreogadus saida) at 1.5°C simulations were carried out, indicating a taurine contribution of about 65% to the in vivo expected CEST effect, if experimental parameters are optimized. B. saida was acutely exposed to three different CO2 concentrations in the sea water (control normocapnia; comparatively moderate hypercapnia OAm = 3300 μatm; high hypercapnia OAh = 4900 μatm). TauCEST imaging of the brain showed a significant increase in the TauCEST effect under the different CO2 concentrations of about 1.5-3% in comparison with control measurements, indicative of changes in pHi or metabolite concentration. Consecutive recordings of 1 H MR spectra gave no support for a concentration induced change of the in vivo observed TauCEST effect. Thus, the in vivo application of TauCEST offers the possibility of mapping relative changes in pHi in the brain of polar cod during exposure to CO2 .
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Affiliation(s)
- Felizitas C Wermter
- University of Bremen, Department of Chemistry, in-vivo-MR Group, Bremen, Germany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - Bastian Maus
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - Hans-O Pörtner
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - Wolfgang Dreher
- University of Bremen, Department of Chemistry, in-vivo-MR Group, Bremen, Germany
| | - Christian Bock
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
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24
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Liu J, Bai R, Li Y, Staedtke V, Zhang S, van Zijl PC, Liu G. MRI detection of bacterial brain abscesses and monitoring of antibiotic treatment using bacCEST. Magn Reson Med 2018; 80:662-671. [PMID: 29577382 PMCID: PMC5910221 DOI: 10.1002/mrm.27180] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/20/2018] [Accepted: 02/24/2018] [Indexed: 12/24/2022]
Abstract
PURPOSE To develop a new MRI method to detect and characterize brain abscesses using the CEST contrast inherently carried by bacterial cells, namely bacCEST. METHODS Bacteria S. aureus (ATCC #49775) and F98 and 9L glioma cells were injected stereotactically in the brains of F344 rats to form abscesses and tumors. The CEST signals of brain abscesses (n = 4) and tumors (n = 7) were acquired using 2 B1 values (i.e., 1 and 3 µT) and compared. The bacCEST signal of the brain abscesses in the rats (n = 3) receiving ampicillin (intraperitoneal injection 40 mg/kg twice daily) was acquired before, 4 and 10 days after the treatment. RESULTS The bacCEST signal of S. aureus was characterized in vitro as a strong and broad signal in the range of 1 to 4 ppm, with the maximum contrast occurring at 2.6 ppm. The CEST signal in S. aureus-induced brain abscesses was significantly higher than that of contralateral parenchyma (p = .003). Moreover, thanks to their different B1 independence, brain abscesses and tumors could be effectively differentiated (p = .005) using ΔCEST(2.6 ppm, 3 µT-1 µT), defined by the difference between the CEST signal (offset = 2.6 ppm) acquired using B1 = 3 µT and that of 1 µT. In treated rats, bacCEST MRI could detect the response of bacteria as early as 4 days after the antibiotic treatment (p = .035). CONCLUSION BacCEST MRI provides a new imaging method to detect, discriminate, and monitor bacterial infection in deep-seated organs. Because no contrast agent is needed, such an approach has a great translational potential for detecting and monitoring bacterial infection in deep-seated organs.
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Affiliation(s)
- Jing Liu
- Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, Guangzhou, Guangdong, China
- Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Graduate College, Southern Medical University, Guangzhou, Guangdong, China
| | - Renyuan Bai
- Department of Neurology and Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Verena Staedtke
- Department of Neurology and Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shuixing Zhang
- The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
| | - Peter C.M. van Zijl
- Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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25
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Xu X, Xu J, Chan KWY, Liu J, Liu H, Li Y, Chen L, Liu G, van Zijl PCM. GlucoCEST imaging with on-resonance variable delay multiple pulse (onVDMP) MRI. Magn Reson Med 2018; 81:47-56. [PMID: 30058240 DOI: 10.1002/mrm.27364] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/16/2022]
Abstract
PURPOSE To examine the detection sensitivity for the rapidly exchanging hydroxyl protons of D-glucose using the recently developed on-resonance variable delay multi-pulse (onVDMP) chemical exchange saturation transfer (CEST) technique. METHODS The onVDMP method was applied for the detection of water signal changes upon venous D-glucose infusion in mice with 9L glioma xenografts. The effect size of onVDMP MRI during infusion was compared with that of conventional continuous wave (CW) CEST MRI. RESULTS Both methods highlighted the tumor and the blood vessels on D-glucose infusion. In interleaved studies, the mean signal changes detected by onVDMP were found to be 1.8 times higher than those by CW-CEST, attributed to its high labeling efficiency for fast exchanging protons and the labeling of the OH protons over a larger frequency range. CONCLUSIONS The onVDMP method is a more sensitive technique for the detection of exogenous CEST agents with fast-exchanging protons compared to CW-CEST MRI.
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Affiliation(s)
- Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Kannie W Y Chan
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland.,Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jing Liu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Radiology Department, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Huanling Liu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Ultrasound, Guangzhou Panyu Central Hospital, Guangzhou, China
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Lin Chen
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland.,Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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26
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Chen L, Xu X, Zeng H, Chan KWY, Yadav N, Cai S, Schunke KJ, Faraday N, van Zijl PCM, Xu J. Separating fast and slow exchange transfer and magnetization transfer using off-resonance variable-delay multiple-pulse (VDMP) MRI. Magn Reson Med 2018; 80:1568-1576. [PMID: 29405374 DOI: 10.1002/mrm.27111] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 01/03/2018] [Accepted: 01/08/2018] [Indexed: 12/12/2022]
Abstract
PURPOSE To develop a method that can separate and quantify the fast (>1 kHz) and slow exchange transfer and magnetization transfer components in Z-spectra. METHODS Z-spectra were recorded as a function of mixing time using a train of selective pulses providing variable-delay multipulse build-up curves. Fast and slow transfer components in the Z-spectra were separated and quantified on a voxel-by-voxel basis by fitting the mixing time-dependent CEST signal using a 3-pool model. RESULTS Phantom studies of glutamate solution, bovine serum albumin solution, and hair conditioner showed the capability of the proposed method to separate fast and slow transfer components. In vivo mouse brain studies showed a strong contrast between white matter and gray matter in the slow-transferring map, corresponding to an asymmetric component of the conventional semisolid magnetization transfer contrast. In addition, a fast-transferring proton map was found that was homogeneous across the brain and attributed to the total contributions of the fast-exchanging protons from proteins, metabolites, and a symmetric magnetization transfer contrast component. CONCLUSIONS This new method provides a simple way to extract fast and slow transfer components from the Z-spectrum, leading to novel MRI contrasts, and providing insight into the different magnetization transfer contrast contributions.
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Affiliation(s)
- Lin Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Haifeng Zeng
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Kannie W Y Chan
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Nirbhay Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Kathryn J Schunke
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nauder Faraday
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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27
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Chen L, Zeng H, Xu X, Yadav NN, Cai S, Puts NA, Barker PB, Li T, Weiss RG, van Zijl PCM, Xu J. Investigation of the contribution of total creatine to the CEST Z-spectrum of brain using a knockout mouse model. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3834. [PMID: 28961344 PMCID: PMC5685917 DOI: 10.1002/nbm.3834] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/25/2017] [Accepted: 08/26/2017] [Indexed: 05/08/2023]
Abstract
The current study aims to assign and estimate the total creatine (tCr) signal contribution to the Z-spectrum in mouse brain at 11.7 T. Creatine (Cr), phosphocreatine (PCr) and protein phantoms were used to confirm the presence of a guanidinium resonance at this field strength. Wild-type (WT) and knockout mice with guanidinoacetate N-methyltransferase deficiency (GAMT-/-), which have low Cr and PCr concentrations in the brain, were used to assign the tCr contribution to the Z-spectrum. To estimate the total guanidinium concentrations, two pools for the Z-spectrum around 2 ppm were assumed: (i) a Lorentzian function representing the guanidinium chemical exchange saturation transfer (CEST) at 1.95 ppm in the 11.7-T Z-spectrum; and (ii) a background signal that can be fitted by a polynomial function. Comparison between the WT and GAMT-/- mice provided strong evidence for three types of contribution to the peak in the Z-spectrum at 1.95 ppm, namely proteins, Cr and PCr, the latter fitted as tCr. A ratio of 20 ± 7% (protein) and 80 ± 7% tCr was found in brain at 2 μT and 2 s saturation. Based on phantom experiments, the tCr peak was estimated to consist of about 83 ± 5% Cr and 17 ± 5% PCr. Maps for tCr of mouse brain were generated based on the peak at 1.95 ppm after concentration calibration with in vivo magnetic resonance spectroscopy.
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Affiliation(s)
- Lin Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Haifeng Zeng
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Nirbhay N. Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Nicolaas A. Puts
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Peter B. Barker
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Tong Li
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Robert G. Weiss
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C. M. van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
- Corresponding Author: Jiadi Xu, Ph.D. Kennedy Krieger Institute, Johns Hopkins University School of Medicine, 707 N. Broadway, Baltimore, MD, 21205, , Tel: 443-923-9572, Fax: 443-923-9505
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28
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Affiliation(s)
- KowsalyaDevi Pavuluri
- Russell H. Morgan Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine; Baltimore, Maryland 21205 United States
| | - Michael T. McMahon
- Russell H. Morgan Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine; Baltimore, Maryland 21205 United States
- F. M. Kirby Research Center for Functional Brain Imaging; Kennedy Krieger Research Institute; Baltimore, Maryland 21205 United States
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29
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Zhang S, Liu Z, Grant A, Keupp J, Lenkinski RE, Vinogradov E. Balanced Steady-State Free Precession (bSSFP) from an effective field perspective: Application to the detection of chemical exchange (bSSFPX). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 275:55-67. [PMID: 28012297 PMCID: PMC5810596 DOI: 10.1016/j.jmr.2016.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/02/2016] [Accepted: 12/03/2016] [Indexed: 05/08/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a novel contrast mechanism and it is gaining increasing popularity as many promising applications have been proposed and investigated. Fast and quantitative CEST imaging techniques are further needed in order to increase the applicability of CEST for clinical use as well as to derive quantitative physiological and biological information. Steady-state methods for fast CEST imaging have been reported recently. Here, we observe that an extreme case of these methods is a balanced steady-state free precession (bSSFP) sequence. The bSSFP in itself is sensitive to the exchange processes; hence, no additional saturation or preparation is needed for CEST-like data acquisition. The bSSFP experiment can be regarded as observation during saturation, without separate saturation and acquisition modules as used in standard CEST and similar experiments. One of the differences from standard CEST methods is that the bSSFP spectrum is an XY-spectrum not a Z-spectrum. As the first proof-of-principle step, we have implemented the steady-state bSSFP sequence for chemical exchange detection (bSSFPX) and verified its feasibility in phantom studies. These studies have shown that bSSFPX can achieve exchange-mediated contrast comparable to the standard CEST experiment. Therefore, the bSSFPX method has a potential for fast and quantitative CEST data acquisition.
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Affiliation(s)
- Shu Zhang
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zheng Liu
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Aaron Grant
- Division of MR Research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Robert E Lenkinski
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Elena Vinogradov
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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30
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Jin T, Nicholls FJ, Crum WR, Ghuman H, Badylak SF, Modo M. Diamagnetic chemical exchange saturation transfer (diaCEST) affords magnetic resonance imaging of extracellular matrix hydrogel implantation in a rat model of stroke. Biomaterials 2016; 113:176-190. [PMID: 27816001 DOI: 10.1016/j.biomaterials.2016.10.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/15/2016] [Accepted: 10/27/2016] [Indexed: 12/18/2022]
Abstract
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. In vitro imaging indicated a robust concentration-dependent detection of the ECM precursor and hydrogel at 1.8 and 3.6 ppm, which broadly corresponded to chondroitin sulfate and fibronectin. This detection was robust to changes in pH and improved at 37 °C. In vivo implantation of ECM hydrogel into the stroke cavity in a rat model corresponded macroscopically to the distribution of biomaterial as indicated by histology, but mismatches were also evident. Indeed, CEST imaging detected an endogenous "increased deposition". To account for this endogenous activity, pre-implantation images were subtracted from post-implantation images to yield a selective visualization of hydrogel distribution in the stroke cavity and its evolution over 7 days. The CEST detection of ECM returned to baseline within 3 days due to a decrease in fibronectin and chondroitin sulfate in the hydrogel. The distribution of ECM hydrogel within the stroke cavity is hence feasible in vivo, but further advances are required to warrant a selective long-term monitoring in the context of biodegradation.
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Affiliation(s)
- Tao Jin
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Francesca J Nicholls
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - William R Crum
- Department of Neuroimaging, King's College London, London, UK
| | - Harmanvir Ghuman
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen F Badylak
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michel Modo
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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31
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Zhou Z, Bez M, Tawackoli W, Giaconi J, Sheyn D, de Mel S, Maya MM, Pressman BD, Gazit Z, Pelled G, Gazit D, Li D. Quantitative chemical exchange saturation transfer MRI of intervertebral disc in a porcine model. Magn Reson Med 2016; 76:1677-1683. [PMID: 27670140 DOI: 10.1002/mrm.26457] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/05/2016] [Accepted: 08/16/2016] [Indexed: 01/25/2023]
Abstract
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. Sodium lactate was injected into the IVDs to induce various pH values within the discs ranging from 5 to 7. RESULTS Phantom and animal results revealed that ksw measured using qCEST MRI is highly correlated with pH level. In the animal studies, the relationship can be described as ksw =9.2 × 106 × 10-pH + 196.9, R2 = 0.7883. CONCLUSION The exchange rate between GAG and water protons determined from qCEST MRI is closely correlated with pH value. This technique has the potential to noninvasively measure pH in the IVDs of patients with discogenic pain. Magn Reson Med 76:1677-1683, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zhengwei Zhou
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
| | - Maxim Bez
- Skeletal Biotech Laboratory, The Hebrew University-Hadassah Faculty of Dental Medicine, Ein Kerem, Jerusalem, Israel
| | - Wafa Tawackoli
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Joseph Giaconi
- Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Dmitriy Sheyn
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Sandra de Mel
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Marcel M Maya
- Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Barry D Pressman
- Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Zulma Gazit
- Skeletal Biotech Laboratory, The Hebrew University-Hadassah Faculty of Dental Medicine, Ein Kerem, Jerusalem, Israel.,Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Gadi Pelled
- Skeletal Biotech Laboratory, The Hebrew University-Hadassah Faculty of Dental Medicine, Ein Kerem, Jerusalem, Israel.,Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Dan Gazit
- Skeletal Biotech Laboratory, The Hebrew University-Hadassah Faculty of Dental Medicine, Ein Kerem, Jerusalem, Israel.,Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA.,Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, California, USA
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32
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Jiang W, Zhou IY, Wen L, Zhou X, Sun PZ. A theoretical analysis of chemical exchange saturation transfer echo planar imaging (CEST-EPI) steady state solution and the CEST sensitivity efficiency-based optimization approach. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:415-423. [PMID: 27312932 DOI: 10.1002/cmmi.1699] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 11/11/2022]
Abstract
Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute labile protons and microenvironmental properties, augmenting routine relaxation-based MRI. Recent developments of quantitative CEST (qCEST) analysis such as omega plots and RF-power based ratiometric calculation have extended our ability to elucidate the underlying CEST system beyond the simplistic apparent CEST measurement. CEST MRI strongly varies with experimental factors, including the RF irradiation level and duration as well as repetition time and flip angle. In addition, the CEST MRI effect is typically small, and experimental optimization strategies have to be carefully evaluated in order to enhance the CEST imaging sensitivity. Although routine CEST MRI has been optimized largely based on maximizing the magnitude of the CEST effect, the CEST signal-to-noise (SNR) efficiency provides a more suitable optimization index, particularly when the scan time is constrained. Herein, we derive an analytical solution of the CEST effect that takes into account key experimental parameters including repetition time, imaging flip angle and RF irradiation level, and solve its SNR efficiency. The solution expedites CEST imaging sensitivity calculation, substantially faster than the Bloch-McConnell equation-based numerical simulation approach. In addition, the analytical solution-based SNR formula enables the exhaustive optimization of CEST MRI, which simultaneously predicts multiple optimal parameters such as repetition time, flip angle and RF saturation level based on the chemical shift and exchange rate. The sensitivity efficiency-based optimization approach could simplify and guide imaging of CEST agents, including glycogen, glucose, creatine, gamma-aminobutyric acid and glutamate. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Weiping Jiang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.,State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Iris Yuwen Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Lingyi Wen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China.
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA. .,Department of Radiology, University of Illinois at Chicago, IL, USA.
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33
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Lee JS, Regatte RR, Jerschow A. Bloch Equations for Proton Exchange Reactions in an Aqueous Solution. CONCEPTS IN MAGNETIC RESONANCE. PART A, BRIDGING EDUCATION AND RESEARCH 2016; 45A:e21397. [PMID: 29270098 PMCID: PMC5736163 DOI: 10.1002/cmr.a.21397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The extension of the Bloch equations for acid-base reactions in an aqueous solution is revisited. The acid-base reactions are second-order, and several reactions catalyzed by distinct catalysts may happen simultaneously. By constructing pseudo first-order reactions and assuming fast dissemination of protons from catalysts to solvent water, this extension converges to the well-known Bloch-McConnell equations for a two-site first-order exchange. Thus, explicit relationships between the parameters appearing in the reactions and the Bloch-McConnell equations are established. The dependencies of exchange rates and chemical exchange saturation transfer effects on pH were numerically and experimentally investigated for representative examples.
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Affiliation(s)
- Jae-Seung Lee
- Department of Radiology, New York University, New York, NY 10016, USA
- Department of Chemistry, New York University, New York, NY 10003, USA
| | | | - Alexej Jerschow
- Department of Chemistry, New York University, New York, NY 10003, USA
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34
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Fernández-Cuervo G, Sinharay S, Pagel MD. A CatalyCEST MRI Contrast Agent that Can Simultaneously Detect Two Enzyme Activities. Chembiochem 2016; 17:383-7. [PMID: 26693680 PMCID: PMC4814164 DOI: 10.1002/cbic.201500586] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 12/28/2022]
Abstract
The simultaneous detection of multiple enzyme activities can improve the specificity of disease diagnoses. We therefore synthesized and characterized a diamagnetic chemical exchange saturation transfer (CEST) MRI contrast agent that can simultaneously detect two enzyme activities. Sulfatase and esterase enzymes cleave the ligands of the CEST agent, releasing salicylic acid that can be detected with CEST MRI. Importantly, both enzymes are required to activate the agent to produce a CEST MRI contrast, and the CEST agent was stable without enzyme treatment. These results established that this diamagnetic CEST MRI contrast agent is a platform technology with a modular design that can be potentially exploited to detect other combinations of enzyme activities, which can expand the armamentarium of contrast agents for molecular imaging.
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Affiliation(s)
- Gabriela Fernández-Cuervo
- Department of Pharmaceutical Sciences, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA.
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35
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Wermter FC, Bock C, Dreher W. Investigating GluCEST and its specificity for pH mapping at low temperatures. NMR IN BIOMEDICINE 2015; 28:1507-17. [PMID: 26412088 DOI: 10.1002/nbm.3416] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/19/2015] [Accepted: 08/24/2015] [Indexed: 05/17/2023]
Abstract
Chemical exchange saturation transfer (CEST) from glutamate to water (GluCEST) is a powerful tool for mapping glutamate concentration and intracellular pH. GluCEST could also be helpful to understand the physiology of lower aquatic vertebrates and invertebrates. Therefore, this study aimed to investigate the GluCEST effect and the exchange rate ksw from amine protons of glutamate to water in a broad range of temperatures (1-37°C) and pH (5.5-8.0). Z-spectra were measured from glutamate solutions at different pH values and temperatures and analysed by numerically solving the Bloch-McConnell equation. As expected, a strong dependence of the GluCEST effect and the determined ksw values on pH and temperature was observed. In addition, a strong dependence of the GluCEST effect on phosphate buffer concentration was confirmed. The in vitro data show that GluCEST is detectable in the whole temperature range, even at 1°C. An interpolation function for the exchange rate ksw was determined for the considered range of temperatures and pH values, showing a bijective relation between the exchange rate and pH at a given temperature. To investigate the specificity of GluCEST imaging at low temperatures, the CEST effect was investigated for several metabolites relevant for CEST imaging of the brain. As an example, the contribution of GluCEST to the total CEST effect at 3 ppm was estimated for zebrafish (Danio rerio). It is shown that also at lower temperatures glutamate is the major contributor to the total CEST effect, particularly if the experimental parameters are optimized.
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Affiliation(s)
- Felizitas C Wermter
- University of Bremen, Department of Chemistry, in-vivo-MR Group, Bremen, Germany
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Department of Integrative Ecophysiology, Bremerhaven, Germany
| | - Christian Bock
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Department of Integrative Ecophysiology, Bremerhaven, Germany
| | - Wolfgang Dreher
- University of Bremen, Department of Chemistry, in-vivo-MR Group, Bremen, Germany
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