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Zeng Q, Machado M, Bie C, van Zijl PCM, Malvar S, Li Y, D’souza V, Poon KA, Grimm A, Yadav NN. In vivo characterization of glycogen storage disease type III in a mouse model using glycoNOE MRI. Magn Reson Med 2024; 91:1115-1121. [PMID: 38009988 PMCID: PMC10842402 DOI: 10.1002/mrm.29923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/28/2023] [Accepted: 10/24/2023] [Indexed: 11/29/2023]
Abstract
PURPOSE Glycogen storage disease type III (GSD III) is a rare inherited metabolic disease characterized by excessive accumulation of glycogen in liver, skeletal muscle, and heart. Currently, there are no widely available noninvasive methods to assess tissue glycogen levels and disease load. Here, we use glycogen nuclear Overhauser effect (glycoNOE) MRI to quantify hepatic glycogen levels in a mouse model of GSD III. METHODS Agl knockout mice (n = 13) and wild-type controls (n = 10) were scanned for liver glycogen content using glycoNOE MRI. All mice were fasted for 12 to 16 h before MRI scans. GlycoNOE signal was quantified by fitting the Z-spectrum using a four-pool Voigt lineshape model. Next, the fitted direct water saturation pool was removed and glycoNOE signal was estimated from the integral of the residual Z spectrum within -0.6 to -1.4 ppm. Glycogen concentration was also measured ex vivo using a biochemical assay. RESULTS GlycoNOE MRI clearly distinguished Agl knockout mice from wild-type controls, showing a statistically significant difference in glycoNOE signals in the livers across genotypes. There was a linear correlation between glycoNOE signal and glycogen concentration determined by the biochemical assay. The obtained glycoNOE maps of mouse livers also showed higher glycogen levels in Agl knockout mice compared to wild-type mice. CONCLUSION GlycoNOE MRI was used successfully as a noninvasive method to detect liver glycogen levels in mice, suggesting the potential of this method to be applied to assess glycogen storage diseases.
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Affiliation(s)
- Qing Zeng
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | | | - Chongxue Bie
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Peter C. M. van Zijl
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Sofi Malvar
- Ultragenyx Pharmaceutical Inc., Novato, CA, United States
| | - Yuguo Li
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Valentina D’souza
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | | | - Andrew Grimm
- Ultragenyx Pharmaceutical Inc., Novato, CA, United States
| | - Nirbhay N. Yadav
- Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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Ali SM, Yadav NN, Wirestam R, Singh M, Heo HY, van Zijl PC, Knutsson L. Deep learning-based Lorentzian fitting of water saturation shift referencing spectra in MRI. Magn Reson Med 2023; 90:1610-1624. [PMID: 37279008 PMCID: PMC10524193 DOI: 10.1002/mrm.29718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/27/2023] [Accepted: 05/12/2023] [Indexed: 06/07/2023]
Abstract
PURPOSE Water saturation shift referencing (WASSR) Z-spectra are used commonly for field referencing in chemical exchange saturation transfer (CEST) MRI. However, their analysis using least-squares (LS) Lorentzian fitting is time-consuming and prone to errors because of the unavoidable noise in vivo. A deep learning-based single Lorentzian Fitting Network (sLoFNet) is proposed to overcome these shortcomings. METHODS A neural network architecture was constructed and its hyperparameters optimized. Training was conducted on a simulated and in vivo-paired data sets of discrete signal values and their corresponding Lorentzian shape parameters. The sLoFNet performance was compared with LS on several WASSR data sets (both simulated and in vivo 3T brain scans). Prediction errors, robustness against noise, effects of sampling density, and time consumption were compared. RESULTS LS and sLoFNet performed comparably in terms of RMS error and mean absolute error on all in vivo data with no statistically significant difference. Although the LS method fitted well on samples with low noise, its error increased rapidly when increasing sample noise up to 4.5%, whereas the error of sLoFNet increased only marginally. With the reduction of Z-spectral sampling density, prediction errors increased for both methods, but the increase occurred earlier (at 25 vs. 15 frequency points) and was more pronounced for LS. Furthermore, sLoFNet performed, on average, 70 times faster than the LS-method. CONCLUSION Comparisons between LS and sLoFNet on simulated and in vivo WASSR MRI Z-spectra in terms of robustness against noise and decreased sample resolution, as well as time consumption, showed significant advantages for sLoFNet.
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Affiliation(s)
| | - Nirbhay N. Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Ronnie Wirestam
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Munendra Singh
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Hye-Young Heo
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Peter C. van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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Zhou Y, Bie C, van Zijl PC, Yadav NN. The relayed nuclear Overhauser effect in magnetization transfer and chemical exchange saturation transfer MRI. NMR Biomed 2023; 36:e4778. [PMID: 35642102 PMCID: PMC9708952 DOI: 10.1002/nbm.4778] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/19/2022] [Accepted: 05/29/2022] [Indexed: 05/23/2023]
Abstract
Magnetic resonance (MR) is a powerful technique for noninvasively probing molecular species in vivo but suffers from low signal sensitivity. Saturation transfer (ST) MRI approaches, including chemical exchange saturation transfer (CEST) and conventional magnetization transfer contrast (MTC), allow imaging of low-concentration molecular components with enhanced sensitivity using indirect detection via the abundant water proton pool. Several recent studies have shown the utility of chemical exchange relayed nuclear Overhauser effect (rNOE) contrast originating from nonexchangeable carbon-bound protons in mobile macromolecules in solution. In this review, we describe the mechanisms leading to the occurrence of rNOE-based signals in the water saturation spectrum (Z-spectrum), including those from mobile and immobile molecular sources and from molecular binding. While it is becoming clear that MTC is mainly an rNOE-based signal, we continue to use the classical MTC nomenclature to separate it from the rNOE signals of mobile macromolecules, which we will refer to as rNOEs. Some emerging applications of the use of rNOEs for probing macromolecular solution components such as proteins and carbohydrates in vivo or studying the binding of small substrates are discussed.
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Affiliation(s)
- Yang Zhou
- Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen University Town, Shenzhen, Guangdong 518055 (China)
| | - Chongxue Bie
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
- Department of Information Science and Technology, Northwest University, No.1 Xuefu Avenue, Xi’an, Shanxi 710127 (China)
| | - Peter C.M. van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
| | - Nirbhay N. Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
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Bie C, van Zijl P, Xu J, Song X, Yadav NN. Radiofrequency labeling strategies in chemical exchange saturation transfer MRI. NMR Biomed 2023; 36:e4944. [PMID: 37002814 PMCID: PMC10312378 DOI: 10.1002/nbm.4944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/19/2023] [Accepted: 03/27/2023] [Indexed: 05/23/2023]
Abstract
Chemical exchange saturation transfer (CEST) MRI has generated great interest for molecular imaging applications because it can image low-concentration solute molecules in vivo with enhanced sensitivity. CEST effects are detected indirectly through a reduction in the bulk water signal after repeated perturbation of the solute proton magnetization using one or more radiofrequency (RF) irradiation pulses. The parameters used for these RF pulses-frequency offset, duration, shape, strength, phase, and interpulse spacing-determine molecular specificity and detection sensitivity, thus their judicious selection is critical for successful CEST MRI scans. This review article describes the effects of applying RF pulses on spin systems and compares conventional saturation-based RF labeling with more recent excitation-based approaches that provide spectral editing capabilities for selectively detecting molecules of interest and obtaining maximal contrast.
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Affiliation(s)
- Chongxue Bie
- Department of Information Science and Technology, Northwest University, No.1 Xuefu Avenue, Xi’an, Shaanxi 710127 (China)
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
| | - Peter van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
| | - Xiaolei Song
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)
| | - Nirbhay N. Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore MD 21205 (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205 (USA)
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Yadav NN, Xu J, Heo HY, van Zijl PCM. Special issue on chemical exchange saturation transfer MRI. NMR Biomed 2023; 36:e4960. [PMID: 37182903 DOI: 10.1002/nbm.4960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- Nirbhay N Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hye-Young Heo
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Lehmann PM, Seidemo A, Andersen M, Xu X, Li X, Yadav NN, Wirestam R, Liebig P, Testud F, Sundgren P, van Zijl PCM, Knutsson L. A numerical human brain phantom for dynamic glucose-enhanced (DGE) MRI: On the influence of head motion at 3T. Magn Reson Med 2023; 89:1871-1887. [PMID: 36579955 PMCID: PMC9992166 DOI: 10.1002/mrm.29563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 11/09/2022] [Accepted: 12/07/2022] [Indexed: 12/30/2022]
Abstract
PURPOSE Dynamic glucose-enhanced (DGE) MRI relates to a group of exchange-based MRI techniques where the uptake of glucose analogues is studied dynamically. However, motion artifacts can be mistaken for true DGE effects, while motion correction may alter true signal effects. The aim was to design a numerical human brain phantom to simulate a realistic DGE MRI protocol at 3T that can be used to assess the influence of head movement on the signal before and after retrospective motion correction. METHODS MPRAGE data from a tumor patient were used to simulate dynamic Z-spectra under the influence of motion. The DGE responses for different tissue types were simulated, creating a ground truth. Rigid head movement patterns were applied as well as physiological dilatation and pulsation of the lateral ventricles and head-motion-induced B0 -changes in presence of first-order shimming. The effect of retrospective motion correction was evaluated. RESULTS Motion artifacts similar to those previously reported for in vivo DGE data could be reproduced. Head movement of 1 mm translation and 1.5 degrees rotation led to a pseudo-DGE effect on the order of 1% signal change. B0 effects due to head motion altered DGE changes due to a shift in the water saturation spectrum. Pseudo DGE effects were partly reduced or enhanced by rigid motion correction depending on tissue location. CONCLUSION DGE MRI studies can be corrupted by motion artifacts. Designing post-processing methods using retrospective motion correction including B0 correction will be crucial for clinical implementation. The proposed phantom should be useful for evaluation and optimization of such techniques.
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Affiliation(s)
- Patrick M Lehmann
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Anina Seidemo
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Mads Andersen
- Philips Healthcare, Copenhagen, Denmark
- Lund University Bioimaging Centre, Lund University, Lund, Sweden
| | - Xiang Xu
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland, USA
| | - Xu Li
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Ronnie Wirestam
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | | | | | - Pia Sundgren
- Lund University Bioimaging Centre, Lund University, Lund, Sweden
- Department of Radiology, Lund University, Lund, Sweden
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins, University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
- Russell H. Morgan Department of Radiology and Radiological Science, 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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Bie C, van Zijl PCM, Mao D, Yadav NN. Ultrafast Z-spectroscopic imaging in vivo at 3T using through-slice spectral encoding (TS-UFZ). Magn Reson Med 2023; 89:1429-1440. [PMID: 36373181 PMCID: PMC9892239 DOI: 10.1002/mrm.29532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/02/2022] [Accepted: 10/31/2022] [Indexed: 11/15/2022]
Abstract
PURPOSE Acquisition of high-resolution Z-spectra for CEST or magnetization transfer contrast (MTC) MRI requires excessive scan times. Ultrafast Z-spectroscopy (UFZ) has been proposed to address this; however, the quality of in vivo UFZ spectra has been insufficient. Here, we present a simple approach to improve this. THEORY AND METHODS UFZ imaging acquires full Z-spectra by encoding the spectral dimension spatially via a gradient applied concurrently with the RF saturation pulse. Different from previous implementations, both this saturation gradient and its readout were applied in the slice direction, resulting in a relatively uniform voxel composition. Phase-encoding was applied in both in-plane directions, allowing additional under-sampling and acceleration. RESULTS In phantoms, UFZ imaging with through-slice Z-spectral encoding (TS-UFZ) provided Z-spectra of salicylic acid and egg white in excellent agreement with conventional acquisitions. In vivo brain Z-spectra were influenced by flow through the imaging slice which affected the Z-spectral baseline. Still, CEST signals could be quantified after baseline fitting and mapping the residual CEST signal. Amide proton transfer (APT) contrast intensities obtained by TS-UFZ were on the same order of magnitude as conventional CEST but with different contrast across slice which likely is a result of different tissue regions contributing. CONCLUSION TS-UFZ approach improves signal stability and spectral uniformity over previous implementations and allows high spectral-resolution imaging of saturation transfer effects in the human brain at 3T. This implementation allows for further acceleration by reducing phase encoding steps and thus opens up the possibility of mapping dynamic CEST signals in vivo with a practical temporal resolution.
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Affiliation(s)
- Chongxue Bie
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore MD (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- Department of Information Science and Technology, Northwest University, Xi’an, Shaanxi (China)
| | - Peter C. M. van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore MD (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Deng Mao
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore MD (USA)
- Philips Healthcare, Baltimore, MD (USA)
| | - Nirbhay N. Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore MD (USA)
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
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Zhou Y, Bie C, van Zijl PCM, Xu J, Zou C, Yadav NN. Detection of electrostatic molecular binding using the water proton signal. Magn Reson Med 2022; 88:901-915. [PMID: 35394084 PMCID: PMC9232913 DOI: 10.1002/mrm.29230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/07/2022] [Accepted: 02/22/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE Saturation transfer MRI has previously been used to probe molecular binding interactions with signal enhancement via the water signal. Here, we detail the relayed nuclear overhauser effect (rNOE) based mechanisms of this signal enhancement, develop a strategy of quantifying molecular binding affinity, i.e., the dissociation constant ( K D $$ {K}_D $$ ), and apply the method to detect electrostatic binding of several charged small biomolecules. Another goal was to estimate the detection limit for transient receptor-substrate binding. THEORY AND METHODS The signal enhancement mechanism was quantitatively described by a three-step magnetization transfer model, and numerical simulations were performed to verify this theory. The binding equilibria of arginine, choline, and acetyl-choline to anionic resin were studied as a function of ligand concentration, pH, and salt content. Equilibrium dissociation constants ( K D $$ {K}_D $$ ) were determined by fitting the multiple concentration data. RESULTS The numerical simulations indicate that the signal enhancement is sufficient to detect the molecular binding of sub-millimolar (∼100 μM) concentration ligands to low micromolar levels of molecular targets. The measured rNOE signals from arginine, choline, and acetyl-choline binding experiments show that several magnetization transfer pathways (intra-ligand rNOEs and intermolecular rNOEs) can contribute. The rNOEs that arise from molecular ionic binding were influenced by pH and salt concentration. The molecular binding strengths in terms of K D $$ {K}_{\mathrm{D}} $$ ranged from 70-160 mM for the three cations studied. CONCLUSION The capability to use MRI to detect the transient binding of small substrates paves a pathway towards the detection of micromolar level receptor-substrate binding in vivo.
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Affiliation(s)
- Yang Zhou
- F.M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMDUSA
- The Russell H. Morgan Department of RadiologyThe Johns Hopkins University School of MedicineBaltimoreMDUSA
- Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong ProvinceShenzhen Institute of Advanced Technology, Chinese Academy of SciencesShenzhenGuangdongChina
| | - Chongxue Bie
- F.M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMDUSA
- The Russell H. Morgan Department of RadiologyThe Johns Hopkins University School of MedicineBaltimoreMDUSA
- Department of Information Science and TechnologyNorthwest UniversityXi'anChina
| | - Peter C. M. van Zijl
- F.M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMDUSA
- The Russell H. Morgan Department of RadiologyThe Johns Hopkins University School of MedicineBaltimoreMDUSA
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMDUSA
- The Russell H. Morgan Department of RadiologyThe Johns Hopkins University School of MedicineBaltimoreMDUSA
| | - Chao Zou
- Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong ProvinceShenzhen Institute of Advanced Technology, Chinese Academy of SciencesShenzhenGuangdongChina
| | - Nirbhay N. Yadav
- F.M. Kirby Research Center for Functional Brain ImagingKennedy Krieger InstituteBaltimoreMDUSA
- The Russell H. Morgan Department of RadiologyThe Johns Hopkins University School of MedicineBaltimoreMDUSA
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Bie C, Li Y, Zhou Y, Bhujwalla ZM, Song X, Liu G, van Zijl PCM, Yadav NN. Deep learning-based classification of preclinical breast cancer tumor models using chemical exchange saturation transfer magnetic resonance imaging. NMR Biomed 2022; 35:e4626. [PMID: 34668251 PMCID: PMC8876537 DOI: 10.1002/nbm.4626] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/31/2021] [Accepted: 09/11/2021] [Indexed: 05/08/2023]
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging has shown promise for classifying tumors based on their aggressiveness, but CEST contrast is complicated by multiple signal sources and thus prolonged acquisition times are often required to extract the signal of interest. We investigated whether deep learning could help identify pertinent Z-spectral features for distinguishing tumor aggressiveness as well as the possibility of acquiring only the pertinent spectral regions for more efficient CEST acquisition. Human breast cancer cells, MDA-MB-231 and MCF-7, were used to establish bi-lateral tumor xenografts in mice to represent higher and lower aggressive tumors, respectively. A convolutional neural network (CNN)-based classification model, trained on simulated data, utilized Z-spectral features as input to predict labels of different tissue types, including MDA-MB-231, MCF-7, and muscle tissue. Saliency maps reported the influence of Z-spectral regions on classifying tissue types. The model was robust to noise with an accuracy of more than 91.5% for low and moderate noise levels in simulated testing data (SD of noise less than 2.0%). For in vivo CEST data acquired with a saturation pulse amplitude of 2.0 μT, the model had a superior ability to delineate tissue types compared with Lorentzian difference (LD) and magnetization transfer ratio asymmetry (MTRasym ) analysis, classifying tissues to the correct types with a mean accuracy of 85.7%, sensitivity of 81.1%, and specificity of 94.0%. The model's performance did not improve substantially when using data acquired at multiple saturation pulse amplitudes or when adding LD or MTRasym spectral features, and did not change when using saliency map-based partial or downsampled Z-spectra. This study demonstrates the potential of CNN-based classification to distinguish between different tumor types and muscle tissue, and speed up CEST acquisition protocols.
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Affiliation(s)
- Chongxue Bie
- Department of Information Science and Technology, Northwest University, Xi'an, Shaanxi, China
- The Russell H. Morgan Department of Radiology, 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
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology, 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
| | - Yang Zhou
- The Russell H. Morgan Department of Radiology, 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
| | - Zaver M Bhujwalla
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xiaolei Song
- Department of Information Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology, 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
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology, 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
| | - Nirbhay N Yadav
- The Russell H. Morgan Department of Radiology, 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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10
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Seidemo A, Lehmann PM, Rydhög A, Wirestam R, Helms G, Zhang Y, Yadav NN, Sundgren PC, van Zijl PC, Knutsson L. Towards robust glucose chemical exchange saturation transfer imaging in humans at 3 T: Arterial input function measurements and the effects of infusion time. NMR Biomed 2022; 35:e4624. [PMID: 34585813 PMCID: PMC9128843 DOI: 10.1002/nbm.4624] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 07/24/2021] [Accepted: 09/01/2021] [Indexed: 05/27/2023]
Abstract
Dynamic glucose-enhanced (DGE) magnetic resonance imaging (MRI) has shown potential for tumor imaging using D-glucose as a biodegradable contrast agent. The DGE signal change is small at 3 T (around 1%) and accurate detection is hampered by motion. The intravenous D-glucose injection is associated with transient side effects that can indirectly generate subject movements. In this study, the aim was to study DGE arterial input functions (AIFs) in healthy volunteers at 3 T for different scanning protocols, as a step towards making the glucose chemical exchange saturation transfer (glucoCEST) protocol more robust. Two different infusion durations (1.5 and 4.0 min) and saturation frequency offsets (1.2 and 2.0 ppm) were used. The effect of subject motion on the DGE signal was studied by using motion estimates retrieved from standard retrospective motion correction to create pseudo-DGE maps, where the apparent DGE signal changes were entirely caused by motion. Furthermore, the DGE AIFs were compared with venous blood glucose levels. A significant difference (p = 0.03) between arterial baseline and postinfusion DGE signal was found after D-glucose infusion. The results indicate that the measured DGE AIF signal change depends on both motion and blood glucose concentration change, emphasizing the need for sufficient motion correction in glucoCEST imaging. Finally, we conclude that a longer infusion duration (e.g. 3-4 min) should preferably be used in glucoCEST experiments, because it can minimize the glucose infusion side effects without negatively affecting the DGE signal change.
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Affiliation(s)
- Anina Seidemo
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | | | - Anna Rydhög
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund and Malmö, Sweden
| | - Ronnie Wirestam
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Gunther Helms
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Nirbhay N. Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Pia C. Sundgren
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund and Malmö, Sweden
- Diagnostic Radiology, Department of Clinical Sciences, Lund University, Lund, Sweden
- Lund University Bioimaging Center, Lund University, Lund, Sweden
| | - Peter C.M. van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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11
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Zhou Y, van Zijl PCM, Xu J, Yadav NN. Mechanism and quantitative assessment of saturation transfer for water-based detection of the aliphatic protons in carbohydrate polymers. Magn Reson Med 2020; 85:1643-1654. [PMID: 32970889 DOI: 10.1002/mrm.28503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/20/2020] [Accepted: 08/10/2020] [Indexed: 12/23/2022]
Abstract
PURPOSE CEST MRI experiments of mobile macromolecules, for example, proteins, carbohydrates, and phospholipids, often show signals due to saturation transfer from aliphatic protons to water. Currently, the mechanism of this nuclear Overhauser effect (NOE)-based transfer pathway is not completely understood and could be due either to NOEs directly to bound water or NOEs relayed intramolecularly via exchangeable protons. We used glycogen as a model system to investigate this saturation transfer pathway in sugar polymer solution. METHODS To determine whether proton exchange affected saturation transfer, saturation spectra (Z-spectra) were measured for glycogen solutions of different pH, D2 O/H2 O ratio, and glycogen particle size. A theoretical model was derived to analytically describe the NOE-based signals in these spectra. Numerical simulations were performed to verify this theory, which was further tested by fitting experimental data for different exchange regimes. RESULTS Signal intensities of aliphatic NOEs in Z-spectra of glycogen in D2 O solution were influenced by hydroxyl proton exchange rates, whereas those in H2 O were not. This indicates that the primary transfer pathway is an exchange-relayed NOE from these aliphatic protons to neighboring hydroxyl protons, followed by the exchange to water protons. Experimental data for glycogen solutions in D2 O and H2 O could be analyzed successfully using an analytical theory derived for such relayed NOE transfer, which was further validated using numerical simulations with the Bloch equations. CONCLUSION The predominant mechanism underlying aliphatic signals in Z-spectra of mobile carbohydrate polymers is intramolecular relayed NOE transfer followed by proton exchange.
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Affiliation(s)
- Yang Zhou
- The Russell H. Morgan Department of Radiology, 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
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology, 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
| | - Jiadi Xu
- The Russell H. Morgan Department of Radiology, 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
| | - Nirbhay N Yadav
- The Russell H. Morgan Department of Radiology, 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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12
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Xu X, Sehgal AA, Yadav NN, Laterra J, Blair L, Blakeley J, Seidemo A, Coughlin JM, Pomper MG, Knutsson L, van Zijl PCM. d-glucose weighted chemical exchange saturation transfer (glucoCEST)-based dynamic glucose enhanced (DGE) MRI at 3T: early experience in healthy volunteers and brain tumor patients. Magn Reson Med 2020; 84:247-262. [PMID: 31872916 PMCID: PMC7083699 DOI: 10.1002/mrm.28124] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/30/2019] [Accepted: 11/19/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE Dynamic glucose enhanced (DGE) MRI has shown potential for imaging glucose delivery and blood-brain barrier permeability at fields of 7T and higher. Here, we evaluated issues involved with translating d-glucose weighted chemical exchange saturation transfer (glucoCEST) experiments to the clinical field strength of 3T. METHODS Exchange rates of the different hydroxyl proton pools and the field-dependent T2 relaxivity of water in d-glucose solution were used to simulate the water saturation spectra (Z-spectra) and DGE signal differences as a function of static field strength B0 , radiofrequency field strength B1 , and saturation time tsat . Multislice DGE experiments were performed at 3T on 5 healthy volunteers and 3 glioma patients. RESULTS Simulations showed that DGE signal decreases with B0 , because of decreased contributions of glucoCEST and transverse relaxivity, as well as coalescence of the hydroxyl and water proton signals in the Z-spectrum. At 3T, because of this coalescence and increased interference of direct water saturation and magnetization transfer contrast, the DGE effect can be assessed over a broad range of saturation frequencies. Multislice DGE experiments were performed in vivo using a B1 of 1.6 µT and a tsat of 1 second, leading to a small glucoCEST DGE effect at an offset frequency of 2 ppm from the water resonance. Motion correction was essential to detect DGE effects reliably. CONCLUSION Multislice glucoCEST-based DGE experiments can be performed at 3T with sufficient temporal resolution. However, the effects are small and prone to motion influence. Therefore, motion correction should be used when performing DGE experiments at clinical field strengths.
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Affiliation(s)
- 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
| | - Akansha Ashvani Sehgal
- 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
| | - John Laterra
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lindsay Blair
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jaishri Blakeley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anina Seidemo
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Jennifer M. Coughlin
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin G. Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Linda Knutsson
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - 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
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13
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Chen J, Yadav NN, Stait-Gardner T, Gupta A, Price WS, Zheng G. Thiol-water proton exchange of glutathione, cysteine, and N-acetylcysteine: Implications for CEST MRI. NMR Biomed 2020; 33:e4188. [PMID: 31793114 DOI: 10.1002/nbm.4188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 06/10/2023]
Abstract
Amide-, amine-, and hydroxyl-water proton exchange can generate MRI contrast through chemical exchange saturation transfer (CEST). In this study, we show that thiol-water proton exchange can also generate quantifiable CEST effects under near-physiological conditions (pH = 7.2 and 37°C) through the characterization of the pH dependence of thiol proton exchange in phosphate-buffered solutions of glutathione, cysteine, and N-acetylcysteine. The spontaneous, base-catalyzed, and buffer-catalyzed exchange contributions to the thiol exchange were analyzed. The thiol-water proton exchange of glutathione and cysteine was found to be too fast to generate a CEST effect around neutral pH due to significant base catalysis. The thiol-water proton exchange of N-acetylcysteine was found to be much slower, yet still in the fast-exchange regime with significant base and buffer catalysis, resulting in a 9.5% attenuation of the water signal at pH 7.2 in a slice-selective CEST NMR experiment. Furthermore, the N-acetylcysteine thiol CEST was also detectable in human serum albumin and agarose phantoms.
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Affiliation(s)
- Johnny Chen
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Timothy Stait-Gardner
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Abhishek Gupta
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - William S Price
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Gang Zheng
- Nanoscale Organisation and Dynamics Group, School of Science and Health, Western Sydney University, Penrith, NSW, Australia
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14
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Chen H, Liu D, Li Y, Xu X, Xu J, Yadav NN, Zhou S, van Zijl PCM, Liu G. CEST MRI monitoring of tumor response to vascular disrupting therapy using high molecular weight dextrans. Magn Reson Med 2019; 82:1471-1479. [PMID: 31106918 DOI: 10.1002/mrm.27818] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE Vascular disrupting therapy of cancer has become a promising approach not only to regress tumor growth directly but also to boost the delivery of chemotherapeutics in the tumor. An imaging approach to monitor the changes in tumor vascular permeability, therefore, has important applications for monitoring of vascular disrupting therapies. METHODS Mice bearing CT26 subcutaneous colon tumors were injected intravenously with 150 kD dextran (Dex150, diameter, d~ 20 nm, 375 mg/kg), tumor necrosis factor-alpha (TNF-α; 1 µg per mouse), or both (n = 3 in each group). The Z-spectra were acquired before and 2 h after the injection, and the chemical exchange saturation transfer (CEST) signals in the tumors as quantified by asymmetric magnetization transfer ratio (MTRasym ) at 1 ppm were compared. RESULTS The results showed a significantly stronger CEST contrast enhancement at 1 ppm (∆MTRasym = 0.042 ± 0.002) in the TNF-α-treated tumors than those by Dex150 alone (∆MTRasym = 0.000 ± 0.005, P = 0.0229) or TNF-α alone (∆MTRasym = 0.002 ± 0.004, P = 0.0264), indicating that the TNF-α treatment strongly augmented the tumor uptake of 150 kD dextran. The MRI findings were verified by fluorescence imaging and immunofluorescence microscopy. CONCLUSIONS High molecular weight dextrans can be used as safe and sensitive CEST MRI contrast agents for monitoring tumor response to vascular disrupting therapy and, potentially, for developing dextran-based theranostic drug delivery systems.
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Affiliation(s)
- Hanwei Chen
- Department of Radiology, Guangzhou Panyu Central Hospital, Guangzhou, Guangdong, China.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Dexiang Liu
- Department of Radiology, Guangzhou Panyu Central Hospital, Guangzhou, Guangdong, China.,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - 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
| | - 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
| | - Nirbhay N Yadav
- 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
| | - Shibin Zhou
- Ludwig Center, Howard Hughes Medical Institute and Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, 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
| | - 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
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15
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Sehgal AA, Li Y, Lal B, Yadav NN, Xu X, Xu J, Laterra J, van Zijl PCM. CEST MRI of 3-O-methyl-D-glucose uptake and accumulation in brain tumors. Magn Reson Med 2018; 81:1993-2000. [PMID: 30206994 DOI: 10.1002/mrm.27489] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/11/2018] [Accepted: 07/17/2018] [Indexed: 01/02/2023]
Abstract
PURPOSE 3-O-Methyl-D-glucose (3-OMG) is a nonmetabolizable structural analog of glucose that offers potential to be used as a CEST-contrast agent for tumor detection. Here, we explore it for CEST-detection of malignant brain tumors and compare it with D-glucose. METHODS Glioma xenografts of a U87-MG cell line were implanted in five mice. Dynamic 3-OMG weighted images were collected using CEST-MRI at 11.7 T at a single offset of 1.2 ppm, showing the effect of accumulation of the contrast agent in the tumor, following an intravenous injection of 3-OMG (3 g/kg). RESULTS Tumor regions showed higher enhancement as compared to contralateral brain. The CEST contrast enhancement in the tumor region ranged from 2.5-5.0%, while it was 1.5-3.5% in contralateral brain. Previous D-glucose studies of the same tumor model showed an enhancement of 1.5-3.0% and 0.5-1.5% in tumor and contralateral brain, respectively. The signal gradually stabilized to a value that persisted for the length of the scan. CONCLUSIONS 3-OMG shows a CEST contrast enhancement that is approximately twice as much as that of D-glucose for a similar tumor line. In view of its suggested low toxicity and transport properties across the BBB, 3-OMG provides an option to be used as a nonmetallic contrast agent for evaluating brain tumors.
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Affiliation(s)
- Akansha Ashvani Sehgal
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Bachchu Lal
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The 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, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - John Laterra
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The 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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16
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Zhang J, Li Y, Slania S, Yadav NN, Liu J, Wang R, Zhang J, Pomper MG, van Zijl PC, Yang X, Liu G. Phenols as Diamagnetic T 2 -Exchange Magnetic Resonance Imaging Contrast Agents. Chemistry 2018; 24:1259-1263. [PMID: 29266443 PMCID: PMC5786484 DOI: 10.1002/chem.201705772] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Indexed: 01/03/2023]
Abstract
Although T2 -exchange (T2ex ) NMR phenomena have been known for decades, there has been a resurgence of interest to develop T2ex MRI contrast agents. One indispensable advantage of T2ex MR agents is the possibility of using non-toxic and/or bio-compatible diamagnetic compounds with intermediate exchangeable protons. Herein a library of phenol-based compounds is screened and their T2ex contrast (exchange relaxivity, r2ex ) at 9.4 T determined. The T2ex contrast of phenol protons allows direct detection by MRI at a millimolar concentration level. The effect of chemical modification of the phenol on the T2ex MRI contrast through modulation of exchange rate and chemical shift was also studied and provides a guideline for use of endogenous and exogenous phenols for T2ex MRI contrast. As a proof-of-principle application, phenol T2ex contrast can be used to detect enzyme activity in a tyrosinase-catalyzed catechol oxidation reaction.
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Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stephanie Slania
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- The Russell H. Morgan Department of Radiology, 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
| | - Jing Liu
- Graduate College, Southern Medical University, Guangzhou, Guangdong, P. R. China
| | - Rongfu Wang
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Jianhua Zhang
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Martin G Pomper
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C van Zijl
- The Russell H. Morgan Department of Radiology, 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
| | - Xing Yang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Nuclear Medicine, Peking University First Hospital Beijing, P. R. China
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology, 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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17
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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 Biomed 2017; 30:10.1002/nbm.3834. [PMID: 28961344 PMCID: PMC5685917 DOI: 10.1002/nbm.3834] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Abstract
Magnetic Resonance Imaging (MRI) is rarely used for molecular binding studies and never without synthetic metallic labels. We designed an MRI approach that can specifically detect the binding of natural substrates (i.e. no chemical labels). To accomplish such detection of substrate-target interaction only, we exploit (i) the narrow resonance of aliphatic protons in free substrate for selective radio-frequency (RF) labeling and, (ii) the process of immobilisation upon binding to a solid-like target for fast magnetic transfer of this label over protons in the target backbone. This cascade of events is ultimately detected with MRI using magnetic interaction between target and water protons. We prove this principle using caffeine as a substrate in vitro and then apply it in vivo in the mouse brain. The combined effects of continuous labeling (label pumping), dynamic reversible binding, and water detection was found to enhance the detection sensitivity by about two to three orders of magnitude.
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Affiliation(s)
- Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Xing Yang
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Nuclear Medicine, Peking University First Hospital, Beijing, P.R. China
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Wenbo Li
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
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Kentrup D, Bovenkamp P, Busch A, Schuette-Nuetgen K, Pawelski H, Pavenstädt H, Schlatter E, Herrmann KH, Reichenbach JR, Löffler B, Heitplatz B, Van Marck V, Yadav NN, Liu G, van Zijl PCM, Reuter S, Hoerr V. GlucoCEST magnetic resonance imaging in vivo may be diagnostic of acute renal allograft rejection. Kidney Int 2017; 92:757-764. [PMID: 28709641 DOI: 10.1016/j.kint.2017.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 03/20/2017] [Accepted: 04/06/2017] [Indexed: 11/29/2022]
Abstract
Acute cellular renal allograft rejection (AR) frequently occurs after kidney transplantations. It is a sterile T-cell mediated inflammation leading to increased local glucose metabolism. Here we demonstrate in an allogeneic model of Brown Norway rat kidneys transplanted into uninephrectomized Lewis rats the successful implementation of the recently developed glucose chemical exchange saturation transfer (glucoCEST) magnetic resonance imaging. This technique is a novel method to assess and differentiate AR. Renal allografts undergoing AR showed significantly increased glucoCEST contrast ratios of cortex to medulla of 1.61 compared to healthy controls (1.02), syngeneic Lewis kidney to Lewis rat transplants without rejection (0.92), kidneys with ischemia reperfusion injury (0.99) and kidneys affected by cyclosporine A toxicity (1.10). Receiver operating characteristic curve analysis showed an area under the curve value of 0.92, and the glucoCEST contrast ratio predicted AR with a sensitivity of 100% and a specificity of 69% at a threshold level over 1.08. In defined animal models of kidney injuries, the glucoCEST contrast ratios of cortex to medulla correlated positively with mRNA expression levels of T-cell markers (CD3, CD4, CD8a/b), but did not correlate to impaired renal perfusion. Thus, the glucoCEST parameter may be valuable for the assessment and follow up treatment of AR.
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Affiliation(s)
- Dominik Kentrup
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Philipp Bovenkamp
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Annika Busch
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | | | - Helga Pawelski
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Hermann Pavenstädt
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Eberhard Schlatter
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Karl-Heinz Herrmann
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany
| | - Jürgen R Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany
| | - Barbara Heitplatz
- Department of Pathology, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Veerle Van Marck
- Department of Pathology, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany
| | - Nirbhay N Yadav
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Guanshu Liu
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Peter C M van Zijl
- Russel H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, Maryland 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, 707 N. Broadway, Baltimore, Maryland 21205, USA
| | - Stefan Reuter
- Medical Clinic D, University of Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany.
| | - Verena Hoerr
- Department of Clinical Radiology, University Hospital Muenster, Albert-Schweitzer Campus 1, 48149 Muenster, Germany; Institute of Medical Microbiology, Jena University Hospital, Erlanger Allee 101, 07747 Jena, Germany.
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20
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Bar-Shir A, Alon L, Korrer MJ, Lim HS, Yadav NN, Kato Y, Pathak AP, Bulte JWM, Gilad AA. Quantification and tracking of genetically engineered dendritic cells for studying immunotherapy. Magn Reson Med 2017; 79:1010-1019. [PMID: 28480589 DOI: 10.1002/mrm.26708] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/15/2017] [Accepted: 03/18/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE Genetically encoded reporters can assist in visualizing biological processes in live organisms and have been proposed for longitudinal and noninvasive tracking of therapeutic cells in deep tissue. Cells can be labeled in situ or ex vivo and followed in live subjects over time. Nevertheless, a major challenge for reporter systems is to identify the cell population that actually expresses an active reporter. METHODS We have used a nucleoside analog, pyrrolo-2'-deoxycytidine, as an imaging probe for the putative reporter gene, Drosophila melanogaster 2'-deoxynucleoside kinase. Bioengineered cells were imaged in vivo in animal models of brain tumor and immunotherapy using chemical exchange saturation transfer MRI. The number of transduced cells was quantified by flow cytometry based on the optical properties of the probe. RESULTS We performed a comparative analysis of six different cell lines and demonstrate utility in a mouse model of immunotherapy. The proposed technology can be used to quantify the number of labeled cells in a given region, and moreover is sensitive enough to detect less than 10,000 cells. CONCLUSION This unique technology that enables efficient selection of labeled cells followed by in vivo monitoring with both optical and MRI. Magn Reson Med 79:1010-1019, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Amnon Bar-Shir
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lina Alon
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael J Korrer
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Hong Seo Lim
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Yoshinori Kato
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Arvind P Pathak
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jeff W M Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, 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.,Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Assaf A Gilad
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, 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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21
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Li Y, Chen H, Xu J, Yadav NN, Chan KWY, Luo L, McMahon MT, Vogelstein B, van Zijl PCM, Zhou S, Liu G. CEST theranostics: label-free MR imaging of anticancer drugs. Oncotarget 2016; 7:6369-78. [PMID: 26837220 PMCID: PMC4872720 DOI: 10.18632/oncotarget.7141] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 01/28/2016] [Indexed: 11/25/2022] Open
Abstract
Image-guided drug delivery is of great clinical interest. Here, we explored a direct way, namely CEST theranostics, to detect diamagnetic anticancer drugs simply through their inherent Chemical Exchange Saturation Transfer (CEST) MRI signal, and demonstrated its application in image-guided drug delivery of nanoparticulate chemotherapeutics. We first screened 22 chemotherapeutic agents and characterized the CEST properties of representative agents and natural analogs in three major categories, i.e., pyrimidine analogs, purine analogs, and antifolates, with respect to chemical structures. Utilizing the inherent CEST MRI signal of gemcitabine, a widely used anticancer drug, the tumor uptake of the i.v.-injected, drug-loaded liposomes was successfully detected in CT26 mouse tumors. Such label-free CEST MRI theranostics provides a new imaging means, potentially with an immediate clinical impact, to monitor the drug delivery in cancer.
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Affiliation(s)
- Yuguo Li
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanwei Chen
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Radiology, Panyu Central Hospital, Guangzhou, China.,Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kannie W Y Chan
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Liangping Luo
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bert Vogelstein
- Ludwig Center, Howard Hughes Medical Institute and Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shibin Zhou
- Ludwig Center, Howard Hughes Medical Institute and Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guanshu Liu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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22
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Zeng H, Xu J, Yadav NN, McMahon MT, Harden B, Frueh D, van Zijl PCM. (15)N Heteronuclear Chemical Exchange Saturation Transfer MRI. J Am Chem Soc 2016; 138:11136-9. [PMID: 27548755 DOI: 10.1021/jacs.6b06421] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A two-step heteronuclear enhancement approach was combined with chemical exchange saturation transfer (CEST) to magnify (15)N MRI signal of molecules through indirect detection via water protons. Previous CEST studies have been limited to radiofrequency (rf) saturation transfer or excitation transfer employing protons. Here, the signal of (15)N is detected indirectly through the water signal by first inverting selectively protons that are scalar-coupled to (15)N in the urea molecule, followed by chemical exchange of the amide proton to bulk water. In addition to providing a small sensitivity enhancement, this approach can be used to monitor the exchange rates and thus the pH sensitivity of the participating (15)N-bound protons.
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Affiliation(s)
- Haifeng Zeng
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Jiadi Xu
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Nirbhay N Yadav
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | - Michael T McMahon
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
| | | | | | - Peter C M van Zijl
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute , Baltimore, Maryland 21205, United States
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23
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Xu X, Yadav NN, Song X, McMahon MT, Jerschow A, van Zijl PCM, Xu J. Screening CEST contrast agents using ultrafast CEST imaging. J Magn Reson 2016; 265:224-229. [PMID: 26969814 PMCID: PMC4818714 DOI: 10.1016/j.jmr.2016.02.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/09/2016] [Accepted: 02/23/2016] [Indexed: 05/30/2023]
Abstract
A chemical exchange saturation transfer (CEST) experiment can be performed in an ultrafast fashion if a gradient field is applied simultaneously with the saturation pulse. This approach has been demonstrated for studying dia- and para-magnetic CEST agents, hyperpolarized Xe gas and in vivo spectroscopy. In this study we present a simple method for the simultaneous screening of multiple samples. Furthermore, by interleaving a number of saturation and readout periods within the TR, a series of images with different saturation times can be acquired, allowing for the quantification of exchange rates using the variable saturation time (QUEST) approach in a much accelerated fashion, thus enabling high throughput screening of CEST contrast agents.
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Affiliation(s)
- Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States.
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Alexej Jerschow
- Department of Chemistry, New York University, NY, United States
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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24
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Alon L, Kraitchman D, Schär M, Cortez A, Yadav NN, Cook J, Johnston PV, Krimins R, McMahon MT, Zijl PV, Bulte JW, Gilad AA. Cardiac CEST-MRI for tracking stem cell survival and determining the role of CXCL2. J Cardiovasc Magn Reson 2016. [PMCID: PMC5032804 DOI: 10.1186/1532-429x-18-s1-p262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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25
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Xu X, Yadav NN, Knutsson L, Hua J, Kalyani R, Hall E, Laterra J, Blakeley J, Strowd R, Pomper M, Barker P, Chan K, Liu G, McMahon MT, Stevens RD, van Zijl PCM. Dynamic Glucose-Enhanced (DGE) MRI: Translation to Human Scanning and First Results in Glioma Patients. ACTA ACUST UNITED AC 2015; 1:105-114. [PMID: 26779568 PMCID: PMC4710854 DOI: 10.18383/j.tom.2015.00175] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Recent animal studies have shown that d-glucose is a potential biodegradable magnetic resonance imaging (MRI) contrast agent for imaging glucose uptake in tumors. We show herein the first translation of that use of d-glucose to human studies. Chemical exchange saturation transfer (CEST) MRI at a single frequency offset optimized for detecting hydroxyl protons in d-glucose was used to image dynamic signal changes in the human brain at 7 T during and after d-glucose infusion. Dynamic glucose enhanced (DGE) image data from 4 normal volunteers and 3 glioma patients showed a strong signal enhancement in blood vessels, while a spatially varying enhancement was found in tumors. Areas of enhancement differed spatially between DGE and conventional gadolinium-enhanced imaging, suggesting complementary image information content for these 2 types of agents. In addition, different tumor areas enhanced with d-glucose at different times after infusion, suggesting a sensitivity to perfusion-related properties such as substrate delivery and blood-brain barrier (BBB) permeability. These preliminary results suggest that DGE MRI is feasible for studying glucose uptake in humans, providing a time-dependent set of data that contains information regarding arterial input function, tissue perfusion, glucose transport across the BBB and cell membrane, and glucose metabolism.
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Affiliation(s)
- Xiang Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Jun Hua
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Rita Kalyani
- Division of Endocrinology, Diabetes & Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Erica Hall
- Division of Endocrinology, Diabetes & Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - John Laterra
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Jaishri Blakeley
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Roy Strowd
- Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States
| | - Martin Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Peter Barker
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Kannie Chan
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Robert D Stevens
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; Department of Neurology, Oncology, and Neuroscience, The Johns Hopkins Medicine, and The Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD, United States; Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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26
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Xu X, Yadav NN, Zeng H, Jones CK, Zhou J, van Zijl PCM, Xu J. Magnetization transfer contrast-suppressed imaging of amide proton transfer and relayed nuclear overhauser enhancement chemical exchange saturation transfer effects in the human brain at 7T. Magn Reson Med 2015; 75:88-96. [PMID: 26445350 DOI: 10.1002/mrm.25990] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 01/15/2023]
Abstract
PURPOSE To use the variable delay multipulse (VDMP) chemical exchange saturation transfer (CEST) approach to obtain clean amide proton transfer (APT) and relayed Nuclear Overhauser enhancement (rNOE) CEST images in the human brain by suppressing the conventional magnetization transfer contrast (MTC) and reducing the direct water saturation contribution. METHODS The VDMP CEST scheme consists of a train of RF pulses with a specific mixing time. The CEST signal with respect to the mixing time shows distinguishable characteristics for protons with different exchange rates. Exchange rate filtered CEST images are generated by subtracting images acquired at two mixing times at which the MTC signals are equal, while the APT and rNOE-CEST signals differ. Because the subtraction is performed at the same frequency offset for each voxel and the CEST signals are broad, no B0 correction is needed. RESULTS MTC-suppressed APT and rNOE-CEST images of human brain were obtained using the VDMP method. The APT-CEST data show hyperintensity in gray matter versus white matter, whereas the rNOE-CEST images show negligible contrast between gray and white matter. CONCLUSION The VDMP approach provides a simple and rapid way of recording MTC-suppressed APT-CEST and rNOE-CEST images without the need for B0 field correction.
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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, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, 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, 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
| | - Craig K Jones
- Russell H. Morgan Department of Radiology and Radiological Science, 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
| | - Jinyuan Zhou
- Russell H. Morgan Department of Radiology and Radiological Science, 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
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, 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, 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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Bar-Shir A, Yadav NN, Gilad AA, van Zijl PCM, McMahon MT, Bulte JWM. Single (19)F probe for simultaneous detection of multiple metal ions using miCEST MRI. J Am Chem Soc 2014; 137:78-81. [PMID: 25523816 PMCID: PMC4304440 DOI: 10.1021/ja511313k] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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The local presence and concentration
of metal ions in biological
systems has been extensively studied ex vivo using
fluorescent dyes. However, the detection of multiple metal ions in vivo remains a major challenge. We present a magnetic
resonance imaging (MRI)-based method for noninvasive detection of
specific ions that may be coexisting, using the tetrafluorinated derivative
of the BAPTA (TF-BAPTA) chelate as a 19F chelate analogue
of existing optical dyes. Taking advantage of the difference in the
ion-specific 19F nuclear magnetic resonance (NMR) chemical
shift offset (Δω) values between the ion-bound and free
TF-BAPTA, we exploited the dynamic exchange between ion-bound and
free TF-BAPTA to obtain MRI contrast with multi-ion chemical exchange
saturation transfer (miCEST). We demonstrate that TF-BAPTA as a prototype
single 19F probe can be used to separately visualize mixed
Zn2+ and Fe2+ ions in a specific and simultaneous
fashion, without interference from potential competitive ions.
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Affiliation(s)
- Amnon Bar-Shir
- Russell H. Morgan Department of Radiology and Radiological Science, ‡Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, §Department of Biomedical Engineering, ∥Department of Chemical & Biomolecular Engineering, and ⊥Department of Oncology, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
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Song X, Xu J, Xia S, Yadav NN, Lal B, Laterra J, Bulte JWM, van Zijl PCM, McMahon MT. Multi-echo length and offset VARied saturation (MeLOVARS) method for improved CEST imaging. Magn Reson Med 2014; 73:488-96. [PMID: 25516490 DOI: 10.1002/mrm.25567] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/14/2014] [Accepted: 11/14/2014] [Indexed: 12/15/2022]
Abstract
PURPOSE The aim of this study was to develop a technique for rapid collection of chemical exchange saturation transfer images with the saturation varied to modulate signal loss transfer and enhance contrast. METHODS Multi-echo Length and Offset VARied Saturation (MeLOVARS) divides the saturation pulse of length Tsat into N = 3-8 submodules, each consisting of a saturation pulse with length of Tsat /N (∼0.3-1 s), one or more low flip-angle gradient-echo readout(s) and a flip back pulse. This results in N readouts with increasing saturation time from Tsat /N to Tsat without extra scan time. RESULTS For phantoms, eight images with Tsat incremented every 0.5 s from 0.5-4 s were collected simultaneously using MeLOVARS, which allows rapid determination of exchange rates for agent protons. For live mice bearing glioblastomas, the Z-spectra for five different Tsat values from 0.5 to 2.5 s were acquired in a time normally used for one Tsat . With the additional Tsat -dependence information, LOVARS phase maps were produced with a more clearly defined tumor boundary and an estimated 4.3-fold enhanced contrast-to-noise ratio (CNR). We also show that enhancing CNR is achievable by simply averaging the collected images or transforming them using the principal component analysis. CONCLUSIONS MeLOVARS enables collection of multiple saturation-time-weighted images without extra time, producing a LOVARS phase map with increased CNR.
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Affiliation(s)
- Xiaolei Song
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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Yang X, Yadav NN, Song X, Banerjee SR, Edelman H, Minn I, van Zijl PCM, Pomper MG, McMahon MT. Tuning phenols with Intra-Molecular bond Shifted HYdrogens (IM-SHY) as diaCEST MRI contrast agents. Chemistry 2014; 20:15824-32. [PMID: 25302635 PMCID: PMC4309366 DOI: 10.1002/chem.201403943] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Indexed: 01/31/2023]
Abstract
The optimal exchange properties for chemical exchange saturation transfer (CEST) contrast agents on 3 T clinical scanners were characterized using continuous wave saturation transfer, and it was demonstrated that the exchangeable protons in phenols can be tuned to reach these criteria through proper ring substitution. Systematic modification allows the chemical shift of the exchangeable protons to be positioned between 4.8 to 12 ppm from water and enables adjustment of the proton exchange rate to maximize CEST contrast at these shifts. In particular, 44 hydrogen-bonded phenols are investigated for their potential as CEST MRI contrast agents and the stereoelectronic effects on their CEST properties are summarized. Furthermore, a pair of compounds, 2,5-dihydroxyterephthalic acid and 4,6-dihydroxyisophthalic acid, were identified which produce the highest sensitivity through incorporating two exchangeable protons per ring.
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Affiliation(s)
- Xing Yang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Nirbhay N. Yadav
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Xiaolei Song
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Sangeeta Ray Banerjee
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Hannah Edelman
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Il Minn
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Peter C. M. van Zijl
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
| | - Michael T. McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, MD 21287 (USA)
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave. Baltimore, MD 21287 (USA)
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Yadav NN, Xu J, Bar-Shir A, Qin Q, Chan KWY, Grgac K, Li W, McMahon MT, van Zijl PCM. Natural D-glucose as a biodegradable MRI relaxation agent. Magn Reson Med 2014; 72:823-8. [PMID: 24975029 DOI: 10.1002/mrm.25329] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/31/2014] [Accepted: 06/02/2014] [Indexed: 11/06/2022]
Abstract
PURPOSE Demonstrate applicability of natural D-glucose as a T2 MRI contrast agent. METHODS D-glucose solutions were prepared at multiple concentrations and variable pH. The relaxation rate (R2 = 1/T2 ) was measured at 3, 7, and 11.7 T. Additional experiments were performed on blood at 11.7 T. Also, a mouse was infused with D-glucose (3.0 mmol/kg) and dynamic T2 weighted images of the abdomen acquired. RESULTS The transverse relaxation rate depended strongly on glucose concentration and solution pH. A maximum change in R2 was observed around physiological pH (pH 6.8-7.8). The transverse relaxivities at 22°C (pH 7.3) were 0.021, 0.060, and 0.077 s(-1) mM(-1) at 3.0, 7.0, and 11.7 T, respectively. These values showed good agreement with expected values from the Swift-Connick equation. There was no significant dependence on glucose concentration or pH for T1 and the diffusion coefficient for these solutions. The transverse relaxivity in blood at 11.7 T was 0.09 s(-1) mM(-1) . The dynamic in vivo experiment showed a 10% drop in signal intensity after glucose infusion followed by recovery of the signal intensity after about 50-100 s. CONCLUSION Glucose can be used as a T2 contrast agent for MRI at concentrations that are already approved for human use.
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Affiliation(s)
- Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, 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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Bar-Shir A, Liu G, Chan KW, Oskolkov N, Song X, Yadav NN, Walczak P, McMahon MT, van Zijl PCM, Bulte JWM, Gilad AA. Human protamine-1 as an MRI reporter gene based on chemical exchange. ACS Chem Biol 2014; 9:134-8. [PMID: 24138139 DOI: 10.1021/cb400617q] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Genetically engineered reporters have revolutionized the understanding of many biological processes. MRI-based reporter genes can dramatically improve our ability to monitor dynamic gene expression and allow coregistration of subcellular genetic information with high-resolution anatomical images. We have developed a biocompatible MRI reporter gene based on a human gene, the human protamine-1 (hPRM1). The arginine-rich hPRM1 (47% arginine residues) generates high MRI contrast based on the chemical exchange saturation transfer (CEST) contrast mechanism. The 51 amino acid-long hPRM1 protein was fully synthesized using microwave-assisted technology, and the CEST characteristics of this protein were compared to other CEST-based contrast agents. Both bacterial and human cells were engineered to express an optimized hPRM1 gene and showed higher CEST contrast compared to controls. Live cells expressing the hPRM1 reporter gene, and embedded in three-dimensional culture, also generated higher CEST contrast compared to wild-type live cells.
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Affiliation(s)
- Amnon Bar-Shir
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Guanshu Liu
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Kannie W.Y. Chan
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Nikita Oskolkov
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Xiaolei Song
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Nirbhay N. Yadav
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Piotr Walczak
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Michael T. McMahon
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Peter C. M. van Zijl
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Jeff W. M. Bulte
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
- Department
of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Assaf A. Gilad
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
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Moroney BF, Stait-Gardner T, Ghadirian B, Yadav NN, Price WS. Numerical analysis of NMR diffusion measurements in the short gradient pulse limit. J Magn Reson 2013; 234:165-175. [PMID: 23887027 DOI: 10.1016/j.jmr.2013.06.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 06/02/2023]
Abstract
Pulsed gradient spin-echo (PGSE) NMR diffusion measurements provide a powerful technique for probing porous media. The derivation of analytical mathematical models for analysing such experiments is only straightforward for ideal restricting geometries and rapidly becomes intractable as the geometrical complexity increases. Consequently, in general, numerical methods must be employed. Here, a highly flexible method for calculating the results of PGSE NMR experiments in porous systems in the short gradient pulse limit based on the finite element method is presented. The efficiency and accuracy of the method is verified by comparison with the known solutions to simple pore geometries (parallel planes, a cylindrical pore, and a spherical pore) and also to Monte Carlo simulations. The approach is then applied to modelling the more complicated cases of parallel semipermeable planes and a pore hopping model. Finally, the results of a PGSE measurement on a toroidal pore, a geometry for which there is presently no current analytical solution, are presented. This study shows that this approach has great potential for modelling the results of PGSE experiments on real (3D) porous systems. Importantly, the FEM approach provides far greater accuracy in simulating PGSE diffraction data.
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Affiliation(s)
- Benjamin F Moroney
- Nanoscale Organisation and Dynamics Group, University of Western Sydney, Penrith, NSW 2751, Australia
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Yadav NN, Chan KWY, Jones CK, McMahon MT, van Zijl PCM. Time domain removal of irrelevant magnetization in chemical exchange saturation transfer Z-spectra. Magn Reson Med 2013; 70:547-55. [PMID: 23798323 PMCID: PMC3742390 DOI: 10.1002/mrm.24812] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/02/2013] [Accepted: 04/26/2013] [Indexed: 12/27/2022]
Abstract
PURPOSE To evaluate the possibility of processing Z-spectra using time domain analysis. METHODS An inverse Fourier transform (IFT) is applied on Z-spectra, thus transforming the chemical exchange saturation transfer (CEST) data into the time domain. Here, large interfering signals from solvent and semisolid magnetization transfer can be fit and filtered out. The method is demonstrated on a range of phantoms (creatine, a para-CEST agent, and hen egg white) and also in vivo on a mouse brain. RESULTS Using time domain analysis, signal components in Z-spectra could be fit very well, thus enabling irreverent or nuisance components to be removed. The method worked equally well for samples in a solution or a gel where the large contribution from conventional magnetization transfer contrast (MTC) was easily separated out. Results from egg white and mouse brain in vivo data showed that the large water resonance could easily be removed thus allowing the remaining signal to be analyzed without interference from direct water saturation. CONCLUSIONS This method successfully filtered out the large nuisance signals from bulk water and MTC in Z-spectra in a large variety of phantom types and also in vivo. It is expected to be a potentially powerful tool for CEST studies without needing asymmetry analysis.
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Affiliation(s)
- 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
| | - Kannie W. Y. Chan
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Craig K. Jones
- 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
| | - Michael T. McMahon
- 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 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
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Xu J, Yadav NN, Bar-Shir A, Jones CK, Chan KWY, Zhang J, Walczak P, McMahon MT, van Zijl PCM. Variable delay multi-pulse train for fast chemical exchange saturation transfer and relayed-nuclear overhauser enhancement MRI. Magn Reson Med 2013; 71:1798-812. [PMID: 23813483 DOI: 10.1002/mrm.24850] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/25/2013] [Accepted: 05/27/2013] [Indexed: 12/14/2022]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) imaging is a new MRI technology allowing the detection of low concentration endogenous cellular proteins and metabolites indirectly through their exchangeable protons. A new technique, variable delay multi-pulse CEST (VDMP-CEST), is proposed to eliminate the need for recording full Z-spectra and performing asymmetry analysis to obtain CEST contrast. METHODS The VDMP-CEST scheme involves acquiring images with two (or more) delays between radiofrequency saturation pulses in pulsed CEST, producing a series of CEST images sensitive to the speed of saturation transfer. Subtracting two images or fitting a time series produces CEST and relayed-nuclear Overhauser enhancement CEST maps without effects of direct water saturation and, when using low radiofrequency power, minimal magnetization transfer contrast interference. RESULTS When applied to several model systems (bovine serum albumin, crosslinked bovine serum albumin, l-glutamic acid) and in vivo on healthy rat brain, VDMP-CEST showed sensitivity to slow to intermediate range magnetization transfer processes (rate < 100-150 Hz), such as amide proton transfer and relayed nuclear Overhauser enhancement-CEST. Images for these contrasts could be acquired in short scan times by using a single radiofrequency frequency. CONCLUSIONS VDMP-CEST provides an approach to detect CEST effect by sensitizing saturation experiments to slower exchange processes without interference of direct water saturation and without need to acquire Z-spectra and perform asymmetry analysis.
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Affiliation(s)
- Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, 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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Lin CY, Yadav NN, Ratnakar J, Sherry AD, van Zijl PCM. In vivo imaging of paraCEST agents using frequency labeled exchange transfer MRI. Magn Reson Med 2013; 71:286-93. [PMID: 23468384 DOI: 10.1002/mrm.24603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/28/2012] [Indexed: 12/27/2022]
Abstract
PURPOSE A main obstacle to in vivo applications of paramagnetic chemical exchange saturation transfer (paraCEST) is interference from endogenous tissue magnetization transfer contrast (MTC). The suitability of excitation-based frequency labeled exchange transfer (FLEX) to separate out such MTC effects in vivo was tested. METHODS The FLEX sequence measures modulation of the water signal based on the chemical shift evolution of solute proton magnetization as a function of evolution time. Time-domain analysis of this water signal allows identification of different solute components and provides a mechanism to separate out the rapidly decaying MTC components with short effective transverse relaxation time ( T2*) values. RESULTS FLEX imaging of paraCEST agents was possible in vitro in phantoms and in vivo in mouse kidneys and bladder. The results demonstrated that FLEX is capable of separating out the MTC signal from tissues in vivo while providing a quantitative exchange rate for the rapidly exchanging paraCEST water protons by fitting the FLEX time-domain signal to FLEX theory. CONCLUSIONS The first in vivo FLEX images of a paraCEST agent were acquired, which allowed separation of the tissue MTC components. These results show that FLEX imaging has potential for imaging the distribution of functional paraCEST agents in biological tissues.
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Affiliation(s)
- Chien-Yuan Lin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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Yadav NN, Jones CK, Hua J, Xu J, van Zijl PCM. Imaging of endogenous exchangeable proton signals in the human brain using frequency labeled exchange transfer imaging. Magn Reson Med 2013; 69:966-73. [PMID: 23400954 DOI: 10.1002/mrm.24655] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/28/2012] [Accepted: 12/31/2012] [Indexed: 01/01/2023]
Abstract
PURPOSE To image endogenous exchangeable proton signals in the human brain using a recently reported method called frequency labeled exchange transfer (FLEX) MRI. METHODS As opposed to labeling exchangeable protons using saturation (i.e., chemical exchange saturation transfer, or CEST), FLEX labels exchangeable protons with their chemical shift evolution. The use of short high-power frequency pulses allows more efficient labeling of rapidly exchanging protons, while time domain acquisition allows removal of contamination from semi-solid magnetization transfer effects. RESULTS FLEX-based exchangeable proton signals were detected in human brain over the 1-5 ppm frequency range from water. Conventional magnetization transfer contrast and the bulk water signal did not interfere in the FLEX spectrum. The information content of these signals differed from in vivo CEST data in that the average exchange rate of these signals was 350-400 s(-1) , much faster than the amide signal usually detected using direct saturation (∼30 s(-1) ). Similarly, fast exchanging protons could be detected in egg white in the same frequency range where amide and amine protons of mobile proteins and peptides are known to resonate. CONCLUSIONS FLEX MRI in the human brain preferentially detects more rapidly exchanging amide/amine protons compared to traditional CEST experiments, thereby changing the information content of the exchangeable proton spectrum. This has the potential to open up different types of endogenous applications as well as more easy detection of rapidly exchanging protons in diaCEST agents or fast exchanging units such as water molecules in paracest agents without interference of conventional magnetization transfer contrast.
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Affiliation(s)
- Nirbhay N Yadav
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Bar-Shir A, Liu G, Liang Y, Yadav NN, McMahon MT, Walczak P, Nimmagadda S, Pomper MG, Tallman KA, Greenberg MM, van Zijl PCM, Bulte JWM, Gilad AA. Transforming thymidine into a magnetic resonance imaging probe for monitoring gene expression. J Am Chem Soc 2013; 135:1617-24. [PMID: 23289583 DOI: 10.1021/ja312353e] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Synthetic chemistry has revolutionized the understanding of many biological systems. Small compounds that act as agonists and antagonists of proteins, and occasionally as imaging probes, have contributed tremendously to the elucidation of many biological pathways. Nevertheless, the function of thousands of proteins is still elusive, and designing new imaging probes remains a challenge. Through screening and characterization, we identified a thymidine analogue as a probe for imaging the expression of herpes simplex virus type-1 thymidine kinase (HSV1-TK). To detect the probe, we used chemical exchange saturation transfer magnetic resonance imaging (CEST-MRI), in which a dynamic exchange process between an exchangeable proton and the surrounding water protons is used to amplify the desired contrast. Initially, five pyrimidine-based molecules were recognized as putative imaging agents, since their exchangeable imino protons resonate at 5-6 ppm from the water proton frequency and their detection is therefore less affected by endogenous CEST contrast or confounded by direct water saturation. Increasing the pK(a) value of the imino proton by reduction of its 5,6-double bond results in a significant reduction of the exchange rate (k(ex)) between this proton and the water protons. This reduced k(ex) of the dihydropyrimidine nucleosides fulfills the "slow to intermediate regime" condition for generating high CEST-MRI contrast. Consequently, we identified 5-methyl-5,6-dihydrothymidine as the optimal probe and demonstrated its feasibility for in vivo imaging of HSV1-TK. In light of these findings, this new approach can be generalized for designing specific probes for the in vivo imaging of a variety of proteins and enzymes.
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Affiliation(s)
- Amnon Bar-Shir
- Division of MR Research, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Yadav NN, Jones CK, Xu J, Bar-Shir A, Gilad AA, McMahon MT, van Zijl PCM. Detection of rapidly exchanging compounds using on-resonance frequency-labeled exchange (FLEX) transfer. Magn Reson Med 2012; 68:1048-55. [PMID: 22837066 DOI: 10.1002/mrm.24420] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/23/2012] [Accepted: 06/25/2012] [Indexed: 11/06/2022]
Abstract
Frequency-labeled exchange transfer is a promising MRI technique for labeling and detecting exchanging protons of low-concentration solutes through the water signal. Early frequency-labeled exchange studies have used off-resonance excitation-based labeling schemes that are well suited to study rapidly exchanging protons or molecules far from the water resonance (e.g., water in paramagnetic contrast agents) or slowly exchanging protons close to the water resonance (e.g., some amide protons). However, off-resonance labeling is not efficient for rapidly exchanging protons close to water. Here, we show that a new frequency-labeled exchange labeling scheme with excitation pulses applied on the water resonance gives much higher exchange contrast for rapidly exchanging protons resonating close to the water resonance frequency. This labeling scheme is particularly suited for studying rapidly exchanging hydroxyl, amine, and imino protons in diamagnetic chemical exchange saturation transfer agents.
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Affiliation(s)
- Nirbhay N Yadav
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Lin CY, Yadav NN, Friedman JI, Ratnakar J, Sherry AD, van Zijl PCM. Using frequency-labeled exchange transfer to separate out conventional magnetization transfer effects from exchange transfer effects when detecting ParaCEST agents. Magn Reson Med 2012; 67:906-11. [PMID: 22287162 DOI: 10.1002/mrm.24161] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 12/18/2011] [Accepted: 12/20/2011] [Indexed: 12/30/2022]
Abstract
Paramagnetic chemical exchange saturation transfer agents combine the benefits of a large chemical shift difference and a fast exchange rate for sensitive MRI detection. However, the in vivo detection of these agents is hampered by the need for high B(1) fields to allow sufficiently fast saturation before exchange occurs, thus causing interference of large magnetization transfer effects from semisolid macromolecules. A recently developed approach named frequency-labeled exchange transfer utilizes excitation pulses instead of saturation pulses for detecting the exchanging protons. Using solutions and gel phantoms containing the europium (III) complex of DOTA tetraglycinate (EuDOTA-(gly)(-) (4) ), it is shown that frequency-labeled exchange transfer allows the separation of chemical exchange effects and magnetization transfer (MT) effects in the time domain, therefore allowing the study of the individual resonance of rapidly exchanging water molecules (k(ex) >10(4) s(-1) ) without interference from conventional broad-band MT.
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Affiliation(s)
- Chien-Yuan Lin
- University of Texas Southwestern Medical Center, Dallas, TX, USA
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Liu G, Liang Y, Bar-Shir A, Chan KWY, Galpoththawela CS, Bernard SM, Tse T, Yadav NN, Walczak P, McMahon MT, Bulte JWM, van Zijl PCM, Gilad AA. Monitoring enzyme activity using a diamagnetic chemical exchange saturation transfer magnetic resonance imaging contrast agent. J Am Chem Soc 2011; 133:16326-9. [PMID: 21919523 DOI: 10.1021/ja204701x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical exchange saturation transfer (CEST) is a new approach for generating magnetic resonance imaging (MRI) contrast that allows monitoring of protein properties in vivo. In this method, a radiofrequency pulse is used to saturate the magnetization of specific protons on a target molecule, which is then transferred to water protons via chemical exchange and detected using MRI. One advantage of CEST imaging is that the magnetizations of different protons can be specifically saturated at different resonance frequencies. This enables the detection of multiple targets simultaneously in living tissue. We present here a CEST MRI approach for detecting the activity of cytosine deaminase (CDase), an enzyme that catalyzes the deamination of cytosine to uracil. Our findings suggest that metabolism of two substrates of the enzyme, cytosine and 5-fluorocytosine (5FC), can be detected using saturation pulses targeted specifically to protons at +2 ppm and +2.4 ppm (with respect to water), respectively. Indeed, after deamination by recombinant CDase, the CEST contrast disappears. In addition, expression of the enzyme in three different cell lines exhibiting different expression levels of CDase shows good agreement with the CDase activity measured with CEST MRI. Consequently, CDase activity was imaged with high-resolution CEST MRI. These data demonstrate the ability to detect enzyme activity based on proton exchange. Consequently, CEST MRI has the potential to follow the kinetics of multiple enzymes in real time in living tissue.
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Affiliation(s)
- Guanshu Liu
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland 21205, USA
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van Zijl PCM, Yadav NN. Chemical exchange saturation transfer (CEST): what is in a name and what isn't? Magn Reson Med 2011; 65:927-48. [PMID: 21337419 PMCID: PMC3148076 DOI: 10.1002/mrm.22761] [Citation(s) in RCA: 792] [Impact Index Per Article: 60.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/01/2010] [Accepted: 11/24/2010] [Indexed: 12/24/2022]
Abstract
Chemical exchange saturation transfer (CEST) imaging is a relatively new magnetic resonance imaging contrast approach in which exogenous or endogenous compounds containing either exchangeable protons or exchangeable molecules are selectively saturated and after transfer of this saturation, detected indirectly through the water signal with enhanced sensitivity. The focus of this review is on basic magnetic resonance principles underlying CEST and similarities to and differences with conventional magnetization transfer contrast. In CEST magnetic resonance imaging, transfer of magnetization is studied in mobile compounds instead of semisolids. Similar to magnetization transfer contrast, CEST has contributions of both chemical exchange and dipolar cross-relaxation, but the latter can often be neglected if exchange is fast. Contrary to magnetization transfer contrast, CEST imaging requires sufficiently slow exchange on the magnetic resonance time scale to allow selective irradiation of the protons of interest. As a consequence, magnetic labeling is not limited to radio-frequency saturation but can be expanded with slower frequency-selective approaches such as inversion, gradient dephasing and frequency labeling. The basic theory, design criteria, and experimental issues for exchange transfer imaging are discussed. A new classification for CEST agents based on exchange type is proposed. The potential of this young field is discussed, especially with respect to in vivo application and translation to humans.
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Affiliation(s)
- Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Yadav NN, Torres AM, Price WS. NMR q-space imaging of macroscopic pores using singlet spin states. J Magn Reson 2010; 204:346-348. [PMID: 20371196 DOI: 10.1016/j.jmr.2010.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 03/01/2010] [Accepted: 03/16/2010] [Indexed: 05/29/2023]
Abstract
NMR q-space imaging is a powerful non-invasive technique used to determine structural characteristics of pores in applications ranging from medical to material science. To date, the application of q-space imaging has primarily been limited to microscopic pores in part because of limitations of the effective observation time due to relaxation. Here we report on the use of singlet spin states for NMR q-space imaging, which allow significantly greater observation times. This opens the way for studying larger pores in materials such as biological tissue, emulsions, and rocks.
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Affiliation(s)
- Nirbhay N Yadav
- Nanoscale Organisation and Dynamics Group, College of Health and Science, University of Western Sydney, Campbelltown Campus, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
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Yadav NN, Price WS. Impediments to the accurate structural characterisation of a highly concentrated emulsion studied using NMR diffusion diffraction. J Colloid Interface Sci 2009; 338:163-8. [DOI: 10.1016/j.jcis.2009.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 06/04/2009] [Accepted: 06/05/2009] [Indexed: 11/24/2022]
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Yadav NN, Torres AM, Price WS. An improved approach to calibrating high magnetic field gradients for pulsed field gradient experiments. J Magn Reson 2008; 194:25-28. [PMID: 18550401 DOI: 10.1016/j.jmr.2008.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 05/21/2008] [Accepted: 05/21/2008] [Indexed: 05/26/2023]
Abstract
Probes capable of generating short high intensity pulsed magnetic field gradients are commonly used in diffusion studies of systems with very short T(2). Traditional methods of calibrating magnetic field gradients present unique challenges at ultrahigh field strengths and are often inapplicable. Currently the most accurate method of determining magnetic gradient strength is to use the known diffusion coefficient of a standard sample and determine gradient strength from the echo attenuation plot of a diffusion experiment, however, there are problems with finding suitable standards for high intensity gradients. Here, we show that molecules containing at least two receptive nuclei (i.e. one with high and one with low gyromagnetic ratios) are excellent systems for calibrating high intensity gradients.
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Affiliation(s)
- Nirbhay N Yadav
- Nanoscale Organisation and Dynamics Group, College of Health and Science, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
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