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Lee SC, Hariharan H, Arias-Mendoza F, Mizsei G, Nath K, Chawla S, Elliott M, Reddy R, Glickson J. Coherence pathway analysis of J-coupled lipids and lactate and effective suppression of lipids upon the selective multiple quantum coherence lactate editing sequence. Biomed Phys Eng Express 2022; 8. [PMID: 35193126 DOI: 10.1088/2057-1976/ac57ad] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 02/21/2022] [Indexed: 11/11/2022]
Abstract
Objective:The selective multiple quantum coherence (Sel-MQC) sequence is a magnetic resonance spectroscopy (MRS) technique used to detect lactate and suppress co-resonant lipid signalsin vivo. The coherence pathways of J-coupled lipids upon the sequence, however, have not been studied, hindering a logical design of the sequence to fully attenuate lipid signals. The objective of this study is to elucidate the coherence pathways of J-coupled lipids upon the Sel-MQC sequence and find a strategy to effectively suppress lipid signals from these pathways while keeping the lactate signal.Approach:The product operator formalism was used to express the evolutions of the J-coupled spins of lipids and lactate. The transformations of the product operators by the spectrally selective pulses of the sequence were calculated by using the off-resonance rotation matrices. The coherence pathways and the conversion rates of the individual pathways were derived from them. Experiments were performed on phantoms and two human subjects at 3T.Main results:The coherence pathways contributing to the various lipid resonance signals by the Sel-MQC sequence depending on the gradient ratios and RF pulse lengths were identified. Theoretical calculations of the signals from the determined coherence pathways and signal attenuations by gradients matched the experimental data very well. Lipid signals from fatty tissues of the subjects were successfully suppressed to the noise level by using the gradient ratio -0.8:-1:2 or 1:0.8:2. The new gradient ratios kept the lactate signal the same as with the previously used gradient ratio 0:-1:2.Significance:The study has elucidated the coherence pathways of J-coupled lipids upon the Sel-MQC sequence and demonstrated how lipid signals can be effectively suppressed while keeping lactate signals by using information from the coherence pathway analysis. The findings enable applying the Sel-MQC sequence to lactate detection in an environment of high concentrations of lipids.
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Affiliation(s)
- Seung-Cheol Lee
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104-6243, UNITED STATES
| | - Hari Hariharan
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Fernando Arias-Mendoza
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Gabor Mizsei
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Kavindra Nath
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19014, UNITED STATES
| | - Sanjeev Chawla
- University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Mark Elliott
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Ravinder Reddy
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Jerry Glickson
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
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Hadar PN, Kini LG, Nanga RPR, Shinohara RT, Chen SH, Shah P, Wisse LEM, Elliott MA, Hariharan H, Reddy R, Detre JA, Stein JM, Das S, Davis KA. Volumetric glutamate imaging (GluCEST) using 7T MRI can lateralize nonlesional temporal lobe epilepsy: A preliminary study. Brain Behav 2021; 11:e02134. [PMID: 34255437 PMCID: PMC8413808 DOI: 10.1002/brb3.2134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
INTRODUCTION Drug-resistant epilepsy patients show worse outcomes after resection when standard neuroimaging is nonlesional, which occurs in one-third of patients. In prior work, we employed 2-D glutamate imaging, Glutamate Chemical Exchange Saturation Transfer (GluCEST), to lateralize seizure onset in nonlesional temporal lobe epilepsy (TLE) based on increased ipsilateral GluCEST signal in the total hippocampus and hippocampal head. We present a significant advancement to single-slice GluCEST imaging, allowing for three-dimensional analysis of brain glutamate networks. METHODS The study population consisted of four MRI-negative, nonlesional TLE patients (two male, two female) with electrographically identified left temporal onset seizures. Imaging was conducted on a Siemens 7T MRI scanner using the CEST method for glutamate, while the advanced normalization tools (ANTs) pipeline and the Automated Segmentation of the Hippocampal Subfields (ASHS) method were employed for image analysis. RESULTS Volumetric GluCEST imaging was validated in four nonlesional TLE patients showing increased glutamate lateralized to the hippocampus of seizure onset (p = .048, with a difference among ipsilateral to contralateral GluCEST signal percentage ranging from -0.05 to 1.37), as well as increased GluCEST signal in the ipsilateral subiculum (p = .034, with a difference among ipsilateral to contralateral GluCEST signal ranging from 0.13 to 1.57). CONCLUSIONS The ability of 3-D, volumetric GluCEST to localize seizure onset down to the hippocampal subfield in nonlesional TLE is an improvement upon our previous 2-D, single-slice GluCEST method. Eventually, we hope to expand volumetric GluCEST to whole-brain glutamate imaging, thus enabling noninvasive analysis of glutamate networks in epilepsy and potentially leading to improved clinical outcomes.
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Affiliation(s)
- Peter N Hadar
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Lohith G Kini
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Russell T Shinohara
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephanie H Chen
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Preya Shah
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Laura E M Wisse
- Penn Image Computing & Science Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark A Elliott
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Joel M Stein
- Department of Radiology, University of Pennsylvania, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Sandhitsu Das
- Penn Image Computing & Science Lab, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn A Davis
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
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Cember ATJ, Hariharan H, Kumar D, Nanga RPR, Reddy R. Improved method for post-processing correction of B 1 inhomogeneity in glutamate-weighted CEST images of the human brain. NMR Biomed 2021; 34:e4503. [PMID: 33749037 DOI: 10.1002/nbm.4503] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 11/03/2020] [Revised: 02/13/2021] [Accepted: 02/14/2021] [Indexed: 06/12/2023]
Abstract
Glutamate-weighted CEST (gluCEST) imaging is nearly unique in its ability to provide non-invasive, spatially resolved measurements of glutamate in vivo. In this article, we present an improved correction for B1 inhomogeneity of gluCEST images of the human brain. Images were obtained on a Siemens 7.0 T Terra outfitted with a single-volume transmit/32-channel receive phased array head coil. Numerical Bloch-McConnell simulations, fitting and data processing were performed using in-house code written in MATLAB and MEX (MATLAB executable). "Calibration" gluCEST data was acquired and fit with a phenomenological functional form first described here. The resulting surfaces were used to correct experimental data in accordance with a newly developed method. Healthy volunteers of varying ages were used for both fitted "calibration" data and corrected "experimental" data. Simulations allowed us to describe the dependence of CEST at 3.0 ppm (gluCEST) on saturation B1 using a new functional form, whose validity was confirmed by successful fitting to real human data. This functional form was used to parameterize surfaces over the space (B1 , T1 ), which could then be used to correct the signal from each pixel. The resulting images show less signal loss in areas of low B1 and greater contrast than those generated using the previously published method. We demonstrate that, using this method with appropriate nominal saturation B1 , the major limitation of correcting for B1 inhomogeneity becomes the effective flip angle of the acquisition module, rather than inability to correct for inhomogeneous saturation. The lower limit of our correction ability with respect to both saturation and acquisition B1 is about 40% of the nominal value. In summary, we demonstrate a more rigorous and successful approach to correcting gluCEST images for B1 inhomogeneity. Limitations of the method and further improvements to enable correction in regions with severe pathology are discussed.
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Affiliation(s)
- Abigail T J Cember
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dushyant Kumar
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravi P R Nanga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Kumar D, Nanga RPR, Thakuri D, Wilson N, Cember A, Martin ML, Zhu D, Shinohara RT, Qin Q, Hariharan H, Reddy R. Recovery kinetics of creatine in mild plantar flexion exercise using 3D creatine CEST imaging at 7 Tesla. Magn Reson Med 2020; 85:802-817. [PMID: 32820572 DOI: 10.1002/mrm.28463] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 10/25/2019] [Revised: 07/08/2020] [Accepted: 07/14/2020] [Indexed: 11/06/2022]
Abstract
PURPOSE Two-dimensional creatine CEST (2D-CrCEST), with a slice thickness of 10-20 mm and temporal resolution (τRes ) of about 30 seconds, has previously been shown to capture the creatine-recovery kinetics in healthy controls and in patients with abnormal creatine-kinase kinetics following the mild plantar flexion exercise. Since the distribution of disease burden may vary across the muscle length for many musculoskeletal disorders, there is a need to increase coverage in the slice-encoding direction. Here, we demonstrate the feasibility of 3D-CrCEST with τRes of about 30 seconds, and propose an improved voxel-wise B 1 + -calibration approach for CrCEST. METHODS The current 7T study with enrollment of 5 volunteers involved collecting the baseline CrCEST imaging for the first 2 minutes, followed by 2 minutes of plantar flexion exercise and then 8 minutes of postexercise CrCEST imaging, to detect the temporal evolution of creatine concentration following exercise. RESULTS Very good repeatability of 3D-CrCEST findings for activated muscle groups on an intraday and interday basis was established, with coefficient of variance of creatine recovery constants (τCr ) being 7%-15.7%, 7.5%, and 5.8% for lateral gastrocnemius, medial gastrocnemius, and peroneus longus, respectively. We also established a good intraday and interday scan repeatability for 3D-CrCEST and also showed good correspondence between τCr measurements using 2D-CrCEST and 3D-CrCEST acquisitions. CONCLUSION In this study, we demonstrated for the first time the feasibility and the repeatability of the 3D-CrCEST method in calf muscle with improved B 1 + correction to measure creatine-recovery kinetics within a large 3D volume of calf muscle.
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Affiliation(s)
- Dushyant Kumar
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Deepa Thakuri
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Siemens Medical Solutions USA Inc., Malvern, Pennsylvania, USA
| | - Abigail Cember
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Melissa Lynne Martin
- Penn Statistics in Imaging and Visualization Center, Department of Biostatistics and Epidemiology, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Dan Zhu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Russell T Shinohara
- Penn Statistics in Imaging and Visualization Center, Department of Biostatistics and Epidemiology, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Qin Qin
- The 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
| | - Hari Hariharan
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Li Y, Xie D, Cember A, Nanga RPR, Yang H, Kumar D, Hariharan H, Bai L, Detre JA, Reddy R, Wang Z. Accelerating GluCEST imaging using deep learning for B 0 correction. Magn Reson Med 2020; 84:1724-1733. [PMID: 32301185 DOI: 10.1002/mrm.28289] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [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: 08/27/2019] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Glutamate weighted Chemical Exchange Saturation Transfer (GluCEST) MRI is a noninvasive technique for mapping parenchymal glutamate in the brain. Because of the sensitivity to field (B0 ) inhomogeneity, the total acquisition time is prolonged due to the repeated image acquisitions at several saturation offset frequencies, which can cause practical issues such as increased sensitivity to patient motions. Because GluCEST signal is derived from the small z-spectrum difference, it often has a low signal-to-noise-ratio (SNR). We proposed a novel deep learning (DL)-based algorithm armed with wide activation neural network blocks to address both issues. METHODS B0 correction based on reduced saturation offset acquisitions was performed for the positive and negative sides of the z-spectrum separately. For each side, a separate deep residual network was trained to learn the nonlinear mapping from few CEST-weighted images acquired at different ppm values to the one at 3 ppm (where GluCEST peaks) in the same side of the z-spectrum. RESULTS All DL-based methods outperformed the "traditional" method visually and quantitatively. The wide activation blocks-based method showed the highest performance in terms of Structural Similarity Index (SSIM) and peak signal-to-noise ratio (PSNR), which were 0.84 and 25dB respectively. SNR increases in regions of interest were over 8dB. CONCLUSION We demonstrated that the new DL-based method can reduce the entire GluCEST imaging time by ˜50% and yield higher SNR than current state-of-the-art.
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Affiliation(s)
- Yiran Li
- Department of Electrical and Computer Engineering, Temple University, Philadelphia, Pennsylvania, USA
| | - Danfeng Xie
- Department of Electrical and Computer Engineering, Temple University, Philadelphia, Pennsylvania, USA
| | - Abigail Cember
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ravi Prakash Reddy Nanga
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Hanlu Yang
- Department of Electrical and Computer Engineering, Temple University, Philadelphia, Pennsylvania, USA
| | - Dushyant Kumar
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Hari Hariharan
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Li Bai
- Department of Electrical and Computer Engineering, Temple University, Philadelphia, Pennsylvania, USA
| | - John A Detre
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ze Wang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Debnath A, Hariharan H, Nanga RPR, Reddy R, Singh A. Glutamate-Weighted CEST Contrast After Removal of Magnetization Transfer Effect in Human Brain and Rat Brain with Tumor. Mol Imaging Biol 2020; 22:1087-1101. [DOI: 10.1007/s11307-019-01465-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Singh A, Debnath A, Cai K, Bagga P, Haris M, Hariharan H, Reddy R. Evaluating the feasibility of creatine-weighted CEST MRI in human brain at 7 T using a Z-spectral fitting approach. NMR Biomed 2019; 32:e4176. [PMID: 31608510 DOI: 10.1002/nbm.4176] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [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: 06/28/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
The current study aims to evaluate the feasibility of creatine (Cr) chemical exchange saturation transfer (CEST)-weighted MRI at 7 T in the human brain by optimizing the saturation pulse parameters and computing contrast using a Z-spectral fitting approach. The Cr-weighted (Cr-w) CEST contrast was computed from phantoms data. Simulations were carried out to obtain the optimum saturation parameters for Cr-w CEST with lower contribution from other brain metabolites. CEST-w images were acquired from the brains of four human subjects at different saturation parameters. The Cr-w CEST contrast was computed using both asymmetry analysis and Z-spectra fitting approaches (models 1 and 2, respectively) based on Lorentzian functions. For broad magnetization transfer (MT) effect, Gaussian and Super-Lorentzian line shapes were also evaluated. In the phantom study, the Cr-w CEST contrast showed a linear dependence on concentration in physiological range and a nonlinear dependence on saturation parameters. The in vivo Cr-w CEST map generated using asymmetry analysis from the brain represents mixed contrast with contribution from other metabolites as well and relayed nuclear Overhauser effect (rNOE). Simulations provided an estimate for the optimum range of saturation parameters to be used for acquiring brain CEST data. The optimum saturation parameters for Cr-w CEST to be used for brain data were around B1rms = 1.45 μT and duration = 2 seconds. The Z-spectral fitting approach enabled computation of individual components. This also resulted in mitigating the contribution from MT and rNOE to Cr-w CEST contrast, which is a major source of underestimation in asymmetry analysis. The proposed modified z-spectra fitting approach (model 2) is more stable to noise compared with model 1. Cr-w CEST contrast obtained using fitting was 6.98 ± 0.31% in gray matter and 5.45 ± 0.16% in white matter. Optimal saturation parameters reduced the contribution from other CEST effects to Cr-w CEST contrast, and the proposed Z-spectral fitting approach enabled computation of individual components in Z-spectra of the brain. Therefore, it is feasible to compute Cr-w CEST contrast with a lower contribution from other CEST and rNOE.
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Affiliation(s)
- Anup Singh
- CBME, Indian Institute of Technology Delhi, New Delhi, India
- Department of Biomedical Engineering, AIIMS, Delhi, India
| | - Ayan Debnath
- CBME, Indian Institute of Technology Delhi, New Delhi, India
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kejia Cai
- Radiology, University of Illinois at Chicago, Chicago, Illinois
| | - Puneet Bagga
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mohammad Haris
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
- Research Branch, Sidra Medical and Research Center, Doha, Qatar
| | - Hari Hariharan
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravinder Reddy
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
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Bagga P, Hariharan H, Wilson NE, Beer JC, Shinohara RT, Elliott MA, Baur JA, Marincola FM, Witschey WR, Haris M, Detre JA, Reddy R. Single-Voxel 1 H MR spectroscopy of cerebral nicotinamide adenine dinucleotide (NAD + ) in humans at 7T using a 32-channel volume coil. Magn Reson Med 2019; 83:806-814. [PMID: 31502710 DOI: 10.1002/mrm.27971] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/15/2019] [Accepted: 08/06/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE Reliable monitoring of tissue nicotinamide adenine dinucleotide (NAD+ ) concentration may provide insights on its roles in normal and pathological aging. In the present study, we report a 1 H MRS pulse sequence for the in vivo, localized 1 H MRS detection of NAD+ from the human brain. METHODS Studies were carried out on a 7T Siemens MRI scanner using a 32-channel product volume coil. The pulse sequence consisted of a spectrally selective low bandwidth E-BURP-1 90° pulse. PRESS localization was achieved using optimized Shinnar-Le Roux 180° pulses and overlapping gradients were used to minimize the TE. The reproducibility of NAD+ quantification was measured in 11 healthy volunteers. The association of cerebral NAD+ with age was assessed in 16 healthy subjects 26-78 years old. RESULTS Spectra acquired from a voxel placed in subjects' occipital lobe consisted of downfield peaks from the H2 , H4 , and H6 protons of the nicotinamide moiety of NAD+ between 8.9-9.35 ppm. The mean ± SD within-session and between-session coefficients of variation were found to be 6.14 ± 2.03% and 6.09 ± 3.20%, respectively. In healthy volunteers, an age-dependent decline of the NAD+ levels in the brain was also observed (β = -1.24 μM/y, SE = 0.21, P < 0.001). CONCLUSION We demonstrated the feasibility and robustness of a newly developed 1 H MRS technique to measure localized cerebral NAD+ at 7T MRI using a commercially available RF head coil. This technique may be further applied to detect and quantify NAD+ from different regions of the brain as well as from other tissues.
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Affiliation(s)
- Puneet Bagga
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hari Hariharan
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Neil E Wilson
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joanne C Beer
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Russell T Shinohara
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania.,Center for Biomedical Image Computing and Analytics, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mark A Elliott
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph A Baur
- Department of Physiology and Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Walter R Witschey
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mohammad Haris
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.,Research Branch, Sidra Medical and Research Center, Doha, Qatar.,Laboratory Animal Research Center, Qatar University, Doha, Qatar
| | - John A Detre
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravinder Reddy
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
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Neal A, Moffat BA, Stein JM, Nanga RPR, Desmond P, Shinohara RT, Hariharan H, Glarin R, Drummond K, Morokoff A, Kwan P, Reddy R, O'Brien TJ, Davis KA. Glutamate weighted imaging contrast in gliomas with 7 Tesla magnetic resonance imaging. Neuroimage Clin 2019; 22:101694. [PMID: 30822716 PMCID: PMC6396013 DOI: 10.1016/j.nicl.2019.101694] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 01/10/2019] [Accepted: 01/27/2019] [Indexed: 01/04/2023]
Abstract
Introduction Diffuse gliomas are incurable malignancies, which undergo inevitable progression and are associated with seizure in 50–90% of cases. Glutamate has the potential to be an important glioma biomarker of survival and local epileptogenicity if it can be accurately quantified noninvasively. Methods We applied the glutamate-weighted imaging method GluCEST (glutamate chemical exchange saturation transfer) and single voxel MRS (magnetic resonance spectroscopy) at 7 Telsa (7 T) to patients with gliomas. GluCEST contrast and MRS metabolite concentrations were quantified within the tumour region and peritumoural rim. Clinical variables of tumour aggressiveness (prior adjuvant therapy and previous radiological progression) and epilepsy (any prior seizures, seizure in last month and drug refractory epilepsy) were correlated with respective glutamate concentrations. Images were separated into post-hoc determined patterns and clinical variables were compared across patterns. Results Ten adult patients with a histo-molecular (n = 9) or radiological (n = 1) diagnosis of grade II-III diffuse glioma were recruited, 40.3 +/− 12.3 years. Increased tumour GluCEST contrast was associated with prior adjuvant therapy (p = .001), and increased peritumoural GluCEST contrast was associated with both recent seizures (p = .038) and drug refractory epilepsy (p = .029). We distinguished two unique GluCEST contrast patterns with distinct clinical and radiological features. MRS glutamate correlated with GluCEST contrast within the peritumoural voxel (R = 0.89, p = .003) and a positive trend existed in the tumour voxel (R = 0.65, p = .113). Conclusion This study supports the role of glutamate in diffuse glioma biology. It further implicates elevated peritumoural glutamate in epileptogenesis and altered tumour glutamate homeostasis in glioma aggressiveness. Given the ability to non-invasively visualise and quantify glutamate, our findings raise the prospect of 7 T GluCEST selecting patients for individualised therapies directed at the glutamate pathway. Larger studies with prospective follow-up are required. 7 T GluCEST glioma imaging is feasible, producing high quality quantifiable images. Increased peritumoural GluCEST contrast correlates with drug resistant epilepsy. Increased tumour GluCEST contrast is associated with prior adjuvant therapy. Two GluCEST patterns were identified with distinct clinico-radiological features. GluCEST contrast correlates with MRS glutamate in peritumoural regions.
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Affiliation(s)
- Andrew Neal
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Australia; Department of Neurology, Royal Melbourne Hospital, Australia.
| | - Bradford A Moffat
- Melbourne Node of the National Imaging Facility, Department of Radiology, University of Melbourne, Australia
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, United States
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Patricia Desmond
- Department of Radiology, Royal Melbourne Hospital, Australia; Department of Radiology and Medicine, University of Melbourne, Australia
| | - Russell T Shinohara
- Department of Biostatistics, Epidemiology, and Informatics, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, PA, United States
| | - Hari Hariharan
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Rebecca Glarin
- Department of Radiology, Royal Melbourne Hospital, Australia; Department of Radiology and Medicine, University of Melbourne, Australia
| | - Katharine Drummond
- Department of Neurosurgery, Royal Melbourne Hospital, Australia; Department of Surgery, University of Melbourne, Australia; Melbourne Brain Centre, The Royal Melbourne Hospital, Australia
| | - Andrew Morokoff
- Department of Neurosurgery, Royal Melbourne Hospital, Australia; Department of Surgery, University of Melbourne, Australia
| | - Patrick Kwan
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Australia; Department of Neurology, Royal Melbourne Hospital, Australia; Department of Neuroscience, Central Clinical School, Monash University, Australia; Department of Neurology, The Alfred Hospital Monash University, Australia
| | - Ravinder Reddy
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Terence J O'Brien
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Australia; Department of Neurology, Royal Melbourne Hospital, Australia; Department of Neuroscience, Central Clinical School, Monash University, Australia; Department of Neurology, The Alfred Hospital Monash University, Australia
| | - Kathryn A Davis
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, United States
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Nanga RPR, DeBrosse C, Kumar D, Roalf D, McGeehan B, D'Aquilla K, Borthakur A, Hariharan H, Reddy D, Elliott M, Detre JA, Epperson CN, Reddy R. Reproducibility of 2D GluCEST in healthy human volunteers at 7 T. Magn Reson Med 2018; 80:2033-2039. [PMID: 29802635 PMCID: PMC6107408 DOI: 10.1002/mrm.27362] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [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: 01/11/2018] [Revised: 04/11/2018] [Accepted: 04/24/2018] [Indexed: 01/06/2023]
Abstract
PURPOSE To investigate the reproducibility of gray and white matter glutamate contrast of a brain slice among a small group of healthy volunteers by using the 2D single-slice glutamate CEST (GluCEST) imaging technique. METHODS Six healthy volunteers were scanned multiple times for within-day and between-day reproducibility. One more volunteer was scanned for within-day reproducibility at 7T MRI. Glutamate CEST contrast measurements were calculated for within subjects and among the subjects and the coefficient of variations are reported. RESULTS The GluCEST measurements were highly reproducible in the gray and white matter area of the brain slice, whether it was within-day or between-day with a coefficient of variation of less than 5%. CONCLUSION This preliminary study in a small group of healthy volunteers shows a high degree of reproducibility of GluCEST MRI in brain and holds promise for implementation in studying age-dependent changes in the brain.
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Affiliation(s)
- Ravi Prakash Reddy Nanga
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Catherine DeBrosse
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Dushyant Kumar
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - David Roalf
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Brendan McGeehan
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Kevin D'Aquilla
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Arijitt Borthakur
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Hari Hariharan
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Damodara Reddy
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Mark Elliott
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - John A. Detre
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Cynthia Neill Epperson
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Ravinder Reddy
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
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11
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Zhou R, Bagga P, Nath K, Hariharan H, Mankoff DA, Reddy R. Glutamate-Weighted Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Detects Glutaminase Inhibition in a Mouse Model of Triple-Negative Breast Cancer. Cancer Res 2018; 78:5521-5526. [PMID: 30072394 DOI: 10.1158/0008-5472.can-17-3988] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/25/2018] [Accepted: 07/30/2018] [Indexed: 11/16/2022]
Abstract
Glutamate is an important metabolite of glutaminolysis, a metabolic pathway used by many aggressive cancers, including triple-negative breast cancer (TNBC). With the exception of the brain, in vivo detection of glutamate in tissues using 1H magnetic resonance spectroscopy (MRS) is challenging. Compared with MRS, glutamate-weighted chemical exchange saturation transfer MR imaging (GluCEST MRI) offers a more sensitive detection mechanism that is free of glutamine interference. Here, we developed a robust, highly repeatable GluCEST MRI protocol in mice bearing human TNBC xenografts and treated with a potent glutaminase inhibitor, CB-839. In paired studies, treatment with CB-839 for 2 days reduced the GluCEST asymmetry value compared with baseline (P < 0.05, n = 10). The absolute change of the GluCEST asymmetry value was -2.5 percent points after CB-839 treatment versus +0.3 after vehicle (P < 0.01). Correspondingly, treatment with CB-839 reduced tumor glutamate concentrations by 1.5 mmol/L, consistent with prior calibration between changes of the GluCEST value versus tissue glutamate concentration; CB-839, however, did not change tumor intracellular pH. These results demonstrate in a mouse model of breast cancer the utility of GluCEST MRI to detect the early response to glutaminase inhibition.Significance: A sensitive method enables noninvasive detection of tumor response to inhibitors of glutamine metabolism. Cancer Res; 78(19); 5521-6. ©2018 AACR.
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Affiliation(s)
- Rong Zhou
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Puneet Bagga
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kavindra Nath
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hari Hariharan
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David A Mankoff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravinder Reddy
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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12
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Bagga P, Pickup S, Crescenzi R, Martinez D, Borthakur A, D'Aquilla K, Singh A, Verma G, Detre JA, Greenberg J, Hariharan H, Reddy R. In vivo GluCEST MRI: Reproducibility, background contribution and source of glutamate changes in the MPTP model of Parkinson's disease. Sci Rep 2018; 8:2883. [PMID: 29440753 PMCID: PMC5811435 DOI: 10.1038/s41598-018-21035-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023] Open
Abstract
Glutamate Chemical Exchange Saturation Transfer (GluCEST) MRI is a recently developed technique to image glutamate. In the present study, we evaluated the reproducibility and background contamination to the GluCEST and source of the GluCEST changes in a mouse model of Parkinson's disease. Repeated measurements in five mice demonstrated an intra-animal coefficient of variation (CV) of GluCEST signal to be 2.3 ± 1.3% and inter-animal CV of GluCEST to be 3.3 ± 0.3%. Mice were treated with MPTP to create a localized striatal elevation of glutamate. We found an elevation in the GluCEST contrast of the striatum following MPTP treatment (Control: 23.3 ± 0.8%, n = 16; MPTP: 26.2 ± 0.8%, n = 19; p ≤ 0.001). Additionally, the positive association between glutamate concentration measured via 1H MRS and GluCEST signal was used to estimate background contribution to the measured GluCEST. The contribution of signal from non-glutamate sources was found to be ~28% of the total GluCEST. Immunohistochemical analysis of the brain showed co-localization of glutamate with GFAP in the striatum. This suggests that the elevated glutamate present in the striatum in this mouse model reflects astroglial proliferation or reactivity due to the action of MPTP. The potential of GluCEST as a biomarker for imaging inflammation mediated gliosis is discussed.
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Affiliation(s)
- Puneet Bagga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States.
| | - Stephen Pickup
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Rachelle Crescenzi
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Daniel Martinez
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Arijitt Borthakur
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Anup Singh
- Centre for Biomedical Engineering, Indian institute of Technology, New Delhi, India
| | - Gaurav Verma
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - John A Detre
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Joel Greenberg
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States.
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13
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Roalf DR, Nanga RPR, Rupert PE, Hariharan H, Quarmley M, Calkins ME, Dress E, Prabhakaran K, Elliott MA, Moberg PJ, Gur RC, Gur RE, Reddy R, Turetsky BI. Glutamate imaging (GluCEST) reveals lower brain GluCEST contrast in patients on the psychosis spectrum. Mol Psychiatry 2017; 22:1298-1305. [PMID: 28115738 PMCID: PMC5822706 DOI: 10.1038/mp.2016.258] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 10/19/2016] [Accepted: 12/06/2016] [Indexed: 01/05/2023]
Abstract
Psychosis commonly develops in adolescence or early adulthood. Youths at clinical high risk (CHR) for psychosis exhibit similar, subtle symptoms to those with schizophrenia (SZ). Malfunctioning neurotransmitter systems, such as glutamate, are implicated in the disease progression of psychosis. Yet, in vivo imaging techniques for measuring glutamate across the cortex are limited. Here, we use a novel 7 Tesla MRI glutamate imaging technique (GluCEST) to estimate changes in glutamate levels across cortical and subcortical regions in young healthy individuals and ones on the psychosis spectrum. Individuals on the psychosis spectrum (PS; n=19) and healthy young individuals (HC; n=17) underwent MRI imaging at 3 and 7 T. At 7 T, a single slice GluCEST technique was used to estimate in vivo glutamate. GluCEST contrast was compared within and across the subcortex, frontal, parietal and occipital lobes. Subcortical (χ2 (1)=4.65, P=0.031) and lobular (χ2 (1)=5.17, P=0.023) GluCEST contrast levels were lower in PS compared with HC. Abnormal GluCEST contrast levels were evident in both CHR (n=14) and SZ (n=5) subjects, and correlated differentially, across regions, with clinical symptoms. Our findings describe a pattern of abnormal brain neurochemistry early in the course of psychosis. Specifically, CHR and young SZ exhibit diffuse abnormalities in GluCEST contrast attributable to a major contribution from glutamate. We suggest that neurochemical profiles of GluCEST contrast across cortex and subcortex may be considered markers of early psychosis. GluCEST methodology thus shows promise to further elucidate the progression of the psychosis disease state.
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Affiliation(s)
- David R. Roalf
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Ravi Prakash Reddy Nanga
- Department of Radiology & Center for Magnetic and Optical Imaging, University of Pennsylvania Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Petra E. Rupert
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Hari Hariharan
- Department of Radiology & Center for Magnetic and Optical Imaging, University of Pennsylvania Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Megan Quarmley
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Monica E. Calkins
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Erich Dress
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Karthik Prabhakaran
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Mark A. Elliott
- Department of Radiology & Center for Magnetic and Optical Imaging, University of Pennsylvania Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Paul J. Moberg
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Ruben C. Gur
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Raquel E. Gur
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Ravinder Reddy
- Department of Radiology & Center for Magnetic and Optical Imaging, University of Pennsylvania Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Bruce I. Turetsky
- Neuropsychiatry Section, Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
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14
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Bagga P, Haris M, D'Aquilla K, Wilson NE, Marincola FM, Schnall MD, Hariharan H, Reddy R. Non-caloric sweetener provides magnetic resonance imaging contrast for cancer detection. J Transl Med 2017; 15:119. [PMID: 28558795 PMCID: PMC5450413 DOI: 10.1186/s12967-017-1221-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 03/26/2017] [Accepted: 05/19/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Image contrast enhanced by exogenous contrast agents plays a crucial role in the early detection, characterization, and determination of the precise location of cancers. Here, we investigate the feasibility of using a non-nutritive sweetener, sucralose (commercial name, Splenda), as magnetic resonance imaging (MRI) contrast agent for cancer studies. METHODS High-resolution nuclear-magnetic-resonance spectroscopy and MR studies on sucralose solution phantom were performed to detect the chemical exchange saturation transfer (CEST) property of sucralose hydroxyl protons with bulk water (sucCEST). For the animal experiments, female Fisher rats (F344/NCR) were used to generate 9L-gliosarcoma model. MRI with CEST experiments were performed on anesthetized rats at 9.4 T MR scanner. Following the baseline CEST scans, sucralose solution was intravenously administered in control and tumor bearing rats. CEST acquisitions were continued during and following the administration of sucralose. Following the sucCEST, Gadolinium-diethylenetriamine pentaacetic acid was injected to perform Gd-enhanced imaging for visualizing the tumor. RESULTS The sucCEST contrast in vitro was found to correlate positively with the sucralose concentration and negatively with the pH, indicating the potential of this technique in cancer imaging. In a control animal, the CEST contrast from the brain was found to be unaffected following the administration of sucralose, demonstrating its blood-brain barrier impermeability. In a 9L glioma model, enhanced localized sucCEST contrast in the tumor region was detected while the unaffected brain region showed unaltered CEST effect implying the specificity of sucralose toward the tumorous tissue. The CEST asymmetry plots acquired from the tumor region before and after the sucralose infusion showed elevation of asymmetry at 1 ppm, pointing towards the role of sucralose in increased contrast. CONCLUSIONS We show the feasibility of using sucralose and sucCEST in study of preclinical models of cancer. This study paves the way for the potential development of sucralose and other sucrose derivatives as contrast agents for clinical MRI applications.
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Affiliation(s)
- Puneet Bagga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA
| | - Mohammad Haris
- Research Branch, Sidra Medical and Research Center, Doha, Qatar
| | - Kevin D'Aquilla
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA
| | - Neil E Wilson
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA
| | | | - Mitchell D Schnall
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, Perelman School of Medicine, University of Pennsylvania, 422 Curie Blvd, B1-Stellar-Chance Laboratories, Philadelphia, PA, USA.
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15
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Cai K, Tain RW, Zhou XJ, Damen FC, Scotti AM, Hariharan H, Poptani H, Reddy R. Creatine CEST MRI for Differentiating Gliomas with Different Degrees of Aggressiveness. Mol Imaging Biol 2017; 19:225-232. [PMID: 27541025 PMCID: PMC5824619 DOI: 10.1007/s11307-016-0995-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [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] [Indexed: 10/21/2022]
Abstract
PURPOSE Creatine (Cr) is a major metabolite in the bioenergetic system. Measurement of Cr using conventional MR spectroscopy (MRS) suffers from low spatial resolution and relatively long acquisition times. Creatine chemical exchange saturation transfer (CrCEST) magnetic resonance imaging (MRI) is an emerging molecular imaging method for tissue Cr measurements. Our previous study showed that the CrCEST contrast, obtained through multicomponent Z-spectral fitting, was lower in tumors compared to normal brain, which further reduced with tumor progression. The current study was aimed to investigate if CrCEST MRI can also be useful for differentiating gliomas with different degrees of aggressiveness. PROCEDURES Intracranial 9L gliosarcoma and F98 glioma bearing rats with matched tumor size were scanned with a 9.4 T MRI scanner at two time points. CEST Z-spectra were collected using a customized sequence with a frequency-selective rectangular saturation pulse (B1 = 50 Hz, duration = 3 s) followed by a single-shot readout. Z spectral data were fitted pixel-wise with five Lorentzian functions, and maps of CrCEST peak amplitude, linewidth, and integral were produced. For comparison, single-voxel proton MR spectroscopy (1H-MRS) was performed to quantify and compare the total Cr concentration in the tumor. RESULTS CrCEST contrasts decreased with tumor progression from weeks 3 to 4 in both 9L and F98 phenotypes. More importantly, F98 tumors had significantly lower CrCEST integral compared to 9L tumors. On the other hand, integrals of other Z-spectral components were unable to differentiate both tumor progression and phenotype with limited sample size. CONCLUSIONS Given that F98 is a more aggressive tumor than 9L, this study suggests that CrCEST MRI may help differentiate gliomas with different aggressiveness.
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Affiliation(s)
- Kejia Cai
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
| | - Rong-Wen Tain
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Xiaohong Joe Zhou
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Frederick C Damen
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Alessandro M Scotti
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Hari Hariharan
- The Center for Magnetic Resonance and Optical Imaging, Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harish Poptani
- Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK
| | - Ravinder Reddy
- The Center for Magnetic Resonance and Optical Imaging, Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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16
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Crescenzi R, DeBrosse C, Nanga RPR, Byrne MD, Krishnamoorthy G, D'Aquilla K, Nath H, Morales KH, Iba M, Hariharan H, Lee VMY, Detre JA, Reddy R. Cover Image, Volume 27, Issue 3. Hippocampus 2017. [DOI: 10.1002/hipo.22629] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rachelle Crescenzi
- Department of Biochemistry and Molecular Biophysics (BMB); University of Pennsylvania; Philadelphia Pennsylvania
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Catherine DeBrosse
- Department of Biochemistry and Molecular Biophysics (BMB); University of Pennsylvania; Philadelphia Pennsylvania
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Ravi P. R. Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Matthew D. Byrne
- Center for Neurodegenerative Disease Research (CNDR); University of Pennsylvania; Philadelphia Pennsylvania
| | - Guruprasad Krishnamoorthy
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Hari Nath
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Knashawn H. Morales
- Department of Biostatistics and Epidemiology; University of Pennsylvania; Philadelphia Pennsylvania
| | - Michiyo Iba
- Center for Neurodegenerative Disease Research (CNDR); University of Pennsylvania; Philadelphia Pennsylvania
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
| | - Virginia M. Y. Lee
- Center for Neurodegenerative Disease Research (CNDR); University of Pennsylvania; Philadelphia Pennsylvania
| | - John A. Detre
- Center for Functional Neuroimaging (CfN); University of Pennsylvania; Philadelphia Pennsylvania
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI); University of Pennsylvania; Philadelphia Pennsylvania
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Crescenzi R, DeBrosse C, Nanga RP, Byrne MD, Krishnamoorthy G, D’Aquilla K, Nath H, Morales KH, Iba M, Hariharan H, Lee VM, Detre JA, Reddy R. Longitudinal imaging reveals subhippocampal dynamics in glutamate levels associated with histopathologic events in a mouse model of tauopathy and healthy mice. Hippocampus 2017; 27:285-302. [PMID: 27997993 PMCID: PMC5396955 DOI: 10.1002/hipo.22693] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [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: 03/09/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 11/08/2022]
Abstract
Tauopathies are neurodegenerative disorders characterized by abnormal intracellular aggregates of tau protein, and include Alzheimer's disease, corticobasal degeneration, frontotemporal dementia, and traumatic brain injury. Glutamate metabolism is altered in neurodegenerative disorders manifesting in higher or lower concentrations of glutamate, its transporters or receptors. Previously, glutamate chemical exchange saturation transfer (GluCEST) magnetic resonance imaging (MRI) demonstrated that glutamate levels are reduced in regions of synapse loss in the hippocampus of a mouse model of late-stage tauopathy. We performed a longitudinal GluCEST imaging experiment paired with a cross-sectional study of histologic markers of tauopathy to determine whether (1) early GluCEST changes are associated with synapse loss before volume loss occurs in the hippocampus, and whether (2) subhippocampal dynamics in GluCEST are associated with histopathologic events related to glutamate alterations in tauopathy. Live imaging of the hippocampus in three serial slices was performed without exogenous contrast agents, and subregions were segmented based on a k-means cluster model. Subregions of the hippocampus were analyzed (cornu ammonis CA1, CA3, dentate gyrus DG, and ventricle) in order to associate local MRI-observable changes in glutamate with histological measures of glial cell proliferation (GFAP), synapse density (synaptophysin, VGlut1) and glutamate receptor (NMDA-NR1) levels. Early differences in GluCEST between healthy and tauopathy mice were measured in the CA1 and DG subregions (30% reduction, P ≤ 0.001). Synapse density was also significantly reduced in every subregion of the hippocampus in tauopathy mice by 6 months. Volume was not significantly reduced in any subregion until 13 months. Further, a gradient in glutamate levels was observed in vivo along hippocampal axes that became polarized as tauopathy progressed. Dynamics in hippocampal glutamate levels throughout lifetime were most closely correlated with combined changes in synaptophysin and GFAP, indicating that GluCEST imaging may be a surrogate marker of glutamate concentration in glial cells and at the synaptic level. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Rachelle Crescenzi
- Department of Biochemistry & Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Catherine DeBrosse
- Department of Biochemistry & Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi P.R. Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew D. Byrne
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - Guruprasad Krishnamoorthy
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Kevin D’Aquilla
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Nath
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Knashawn H. Morales
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michiyo Iba
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
| | - Virginia M.Y Lee
- Center for Neurodegenerative Disease Research (CNDR), University of Pennsylvania, Philadelphia, PA, USA
| | - John A. Detre
- Center for Functional Neuroimaging (CfN), University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), University of Pennsylvania, Philadelphia, PA, USA
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Kogan F, Stafford RB, Englund EK, Gold GE, Hariharan H, Detre JA, Reddy R. Perfusion has no effect on the in vivo CEST effect from Cr (CrCEST) in skeletal muscle. NMR Biomed 2017; 30:10.1002/nbm.3673. [PMID: 27898185 PMCID: PMC5518925 DOI: 10.1002/nbm.3673] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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: 09/07/2016] [Revised: 10/13/2016] [Accepted: 10/25/2016] [Indexed: 05/08/2023]
Abstract
Creatine, a key component of muscle energy metabolism, exhibits a chemical exchange saturation transfer (CEST) effect between its amine group and bulk water, which has been exploited to spatially and temporally map creatine changes in skeletal muscle before and after exercise. In addition, exercise leads to an increase in muscle perfusion. In this work, we determined the effects of perfused blood on the CEST effects from creatine in skeletal muscle. Experiments were performed on healthy human subjects (n = 5) on a whole-body Siemens 7T magnetic resonance imaging (MRI) scanner with a 28-channel radiofrequency (RF) coil. Reactive hyperemia, induced by inflation and subsequent deflation of a pressure cuff secured around the thigh, was used to increase tissue perfusion whilst maintaining the levels of creatine kinase metabolites. CEST, arterial spin labeling (ASL) and 31 P MRS data were acquired at baseline and for 6 min after cuff deflation. Reactive hyperemia resulted in substantial increases in perfusion in human skeletal muscle of the lower leg as measured by the ASL mean percentage difference. However, no significant changes in CrCEST asymmetry (CrCESTasym ) or 31 P MRS-derived PCr levels of skeletal muscle were observed following cuff deflation. This work demonstrates that perfusion changes do not have a major confounding effect on CrCEST measurements.
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Affiliation(s)
- Feliks Kogan
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Randall B. Stafford
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Erin K. Englund
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Garry E. Gold
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| | - John A. Detre
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
- Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
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DeBrosse C, Nanga RPR, Wilson N, D'Aquilla K, Elliott M, Hariharan H, Yan F, Wade K, Nguyen S, Worsley D, Parris-Skeete C, McCormick E, Xiao R, Cunningham ZZ, Fishbein L, Nathanson KL, Lynch DR, Stallings VA, Yudkoff M, Falk MJ, Reddy R, McCormack SE. Muscle oxidative phosphorylation quantitation using creatine chemical exchange saturation transfer (CrCEST) MRI in mitochondrial disorders. JCI Insight 2016; 1:e88207. [PMID: 27812541 DOI: 10.1172/jci.insight.88207] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Systemic mitochondrial energy deficiency is implicated in the pathophysiology of many age-related human diseases. Currently available tools to estimate mitochondrial oxidative phosphorylation (OXPHOS) capacity in skeletal muscle in vivo lack high anatomic resolution. Muscle groups vary with respect to their contractile and metabolic properties. Therefore, muscle group-specific estimates of OXPHOS would be advantageous. To address this need, a noninvasive creatine chemical exchange saturation transfer (CrCEST) MRI technique has recently been developed, which provides a measure of free creatine. After exercise, skeletal muscle can be imaged with CrCEST in order to make muscle group-specific measurements of OXPHOS capacity, reflected in the recovery rate (τCr) of free Cr. In this study, we found that individuals with genetic mitochondrial diseases had significantly (P = 0.026) prolonged postexercise τCr in the medial gastrocnemius muscle, suggestive of less OXPHOS capacity. Additionally, we observed that lower resting CrCEST was associated with prolonged τPCr, with a Pearson's correlation coefficient of -0.42 (P = 0.046), consistent with previous hypotheses predicting that resting creatine levels may correlate with 31P magnetic resonance spectroscopy-based estimates of OXPHOS capacity. We conclude that CrCEST can noninvasively detect changes in muscle creatine content and OXPHOS capacity, with high anatomic resolution, in individuals with mitochondrial disorders.
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Affiliation(s)
- Catherine DeBrosse
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark Elliott
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felicia Yan
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Kristin Wade
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Sara Nguyen
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Diana Worsley
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | | | - Elizabeth McCormick
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Rui Xiao
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Lauren Fishbein
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Katherine L Nathanson
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania.,Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania
| | - David R Lynch
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Virginia A Stallings
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marc Yudkoff
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marni J Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shana E McCormack
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Bagga P, Crescenzi R, Krishnamoorthy G, Verma G, Nanga RPR, Reddy D, Greenberg J, Detre JA, Hariharan H, Reddy R. Mapping the alterations in glutamate with GluCEST MRI in a mouse model of dopamine deficiency. J Neurochem 2016; 139:432-439. [PMID: 27529288 DOI: 10.1111/jnc.13771] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [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: 05/07/2016] [Revised: 06/21/2016] [Accepted: 08/05/2016] [Indexed: 11/30/2022]
Abstract
Glutamate chemical exchange saturation transfer (GluCEST) MRI was used to measure metabolic changes in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by mapping regional cerebral glutamate. The GluCEST contrast following MPTP treatment was correlated with 1 H-MR spectroscopy, motor function, and immunohistochemical measures. The GluCEST contrast was found to be significantly higher in the striatum and motor cortex of mice treated with MPTP than in controls (p < 0.001), which was confirmed by localized 1 H-MR spectroscopy. Elevated striatal GluCEST was positively associated with local astrogliosis measured by immunohistochemistry for glial fibrillary acidic protein. Additionally, a negative correlation was found between motor function, measured by the four-limb grip strength test, and GluCEST of the striatum (R = -0.705, p < 0.001) and the motor cortex (R = -0.617, p < 0.01), suggesting a role of elevated glutamate in the abnormal cerebral motor function regulation. The GluCEST contrast and glial fibrillary acidic protein immunostaining were unaltered in the thalamus indicating glutamate elevation was localized to the striatum and the motor cortex. These findings suggest that in addition to measuring spatial changes in glutamate, GluCEST may serve as an in vivo biomarker of metabolic and functional changes that may be applied to the assessment of a broad range of neuropathologies. Read the Editorial Highlight for this article on page 346.
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Affiliation(s)
- Puneet Bagga
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rachelle Crescenzi
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Guruprasad Krishnamoorthy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gaurav Verma
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Damodar Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joel Greenberg
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John A Detre
- Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
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Wilson NE, D'Aquilla K, Debrosse C, Hariharan H, Reddy R. Localized, gradient-reversed ultrafast z-spectroscopy in vivo at 7T. Magn Reson Med 2016; 76:1039-1046. [PMID: 27367138 PMCID: PMC5023501 DOI: 10.1002/mrm.26314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 09/18/2015] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 11/06/2022]
Abstract
PURPOSE To collect ultrafast z-spectra in vivo in situations where voxel homogeneity cannot be assured. THEORY Saturating in the presence of a gradient encodes the frequency offset spatially across a voxel. This encoding can be resolved by applying a similar gradient during readout. Acquiring additional scans with the gradient polarity reversed effectively mirrors the spatial locations of the frequency offsets so that the same physical location of a positive offset in the original scan will contribute a negative offset in the gradient-reversed scan. METHODS Gradient-reversed ultrafast z-spectroscopy (GRUFZS) was implemented and tested in a modified, localized PRESS sequence at 7T. Lysine phantoms were scanned at various concentrations and compared with coventionally-acquired z-spectra. Scans were acquired in vivo in human brain from homogeneous and inhomogeneous voxels with the ultrafast direction cycled between read, phase, and slice. Results were compared to those from a similar conventional z-spectroscopy PRESS-based sequence. RESULTS Asymmetry spectra from GRUFZS are more consistent and reliable than those without gradient reversal and are comparable to those from conventional z-spectroscopy. GRUFZS offers significant acceleration in data acquisition compared to traditional chemical exchange saturation transfer methods with high spectral resolution and showed higher relative SNR effficiency. CONCLUSION GRUFZS offers a method of collecting ultrafast z-spectra in voxels with the inhomogeneity often found in vivo. Magn Reson Med 76:1039-1046, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Neil E. Wilson
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Phildelphia PA
| | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Phildelphia PA
| | - Catherine Debrosse
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Phildelphia PA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Phildelphia PA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Phildelphia PA
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22
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Davis KA, Nanga RPR, Das S, Chen SH, Hadar PN, Pollard JR, Lucas TH, Shinohara RT, Litt B, Hariharan H, Elliott MA, Detre JA, Reddy R. Glutamate imaging (GluCEST) lateralizes epileptic foci in nonlesional temporal lobe epilepsy. Sci Transl Med 2016; 7:309ra161. [PMID: 26468323 DOI: 10.1126/scitranslmed.aaa7095] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
When neuroimaging reveals a brain lesion, drug-resistant epilepsy patients show better outcomes after resective surgery than do the one-third of drug-resistant epilepsy patients who have normal brain magnetic resonance imaging (MRI). We applied a glutamate imaging method, GluCEST (glutamate chemical exchange saturation transfer), to patients with nonlesional temporal lobe epilepsy based on conventional MRI. GluCEST correctly lateralized the temporal lobe seizure focus on visual and quantitative analyses in all patients. MR spectra, available for a subset of patients and controls, corroborated the GluCEST findings. Hippocampal volumes were not significantly different between hemispheres. GluCEST allowed high-resolution functional imaging of brain glutamate and has potential to identify the epileptic focus in patients previously deemed nonlesional. This method may lead to improved clinical outcomes for temporal lobe epilepsy as well as other localization-related epilepsies.
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Affiliation(s)
- Kathryn Adamiak Davis
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sandhitsu Das
- Penn Image Computing & Science Lab, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephanie H Chen
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Peter N Hadar
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John R Pollard
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Timothy H Lucas
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Russell T Shinohara
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brian Litt
- Penn Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hari Hariharan
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark A Elliott
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John A Detre
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance & Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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23
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Nanga RPR, Hariharan H, Reddy R. Fully automated macromolecule suppressed single voxel glutamate spectroscopy (FAMOUS SVGS). J Transl Med 2016; 14:220. [PMID: 27456699 PMCID: PMC4960747 DOI: 10.1186/s12967-016-0970-1] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/11/2016] [Indexed: 11/10/2022] Open
Abstract
PURPOSE The aim of the study was to develop and validate a new localized (1)H MRS pulse sequence and automated post-processing software for the quantification of brain Glutamate (Glu) in clinical conditions at 7.0T in order to get reliable and reproducible results for acute intervention studies. METHODS Here we describe a new localized proton MRS method "Fully Automated MacrOmolecUle Suppressed Single Voxel Glutamate Spectroscopy (FAMOUS SVGS)" for measuring Glu. FAMOUS SVGS method consists of a new pulse sequence with optimized switchable water, metabolites and outer volume suppression modules, as well as a frequency selective inversion pulse and automated post-processing of the five spectra obtained. FAMOUS SVGS method was first validated with glutamate phantoms and then validated with test-retest repeatability studies in the occipital cortex of five normal volunteers at 7.0T. RESULTS Glutamate concentrations estimated from phantoms with FAMOUS SVGS method correlated well with actual concentrations. Test-retest repeatability studies in human brain in vivo yielded less than 0.3 mM intra-subject variations in Glu concentrations. CONCLUSIONS FAMOUS SVGS method enables Glu quantification in vivo at 7.0T with test-retest variability of less than 0.3 mM. We expect that we can reliably measure ≥0.5 mM change in glutamate due to any acute intervention.
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Affiliation(s)
- Ravi Prakash Reddy Nanga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA.
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA
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24
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Krishnamoorthy G, Nanga RPR, Bagga P, Hariharan H, Reddy R. High quality three-dimensional gagCEST imaging of in vivo human knee cartilage at 7 Tesla. Magn Reson Med 2016; 77:1866-1873. [PMID: 27174078 DOI: 10.1002/mrm.26265] [Citation(s) in RCA: 42] [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: 10/15/2015] [Revised: 04/10/2016] [Accepted: 04/14/2016] [Indexed: 11/10/2022]
Abstract
PURPOSE To develop a new faster and higher quality three-dimensional (3D) gagCEST MRI technique for reliable quantification of glycosaminoglycan (GAG) present in the human knee cartilages. METHODS A new magnetization-prepared 3D gradient echo-based MRI pulse sequence has been designed to obtain the B0 inhomogeneity, B1 inhomogeneity, and CEST Z-spectra images. RESULTS The gagCEST values of different compartments of knee cartilage are calculated using a newly developed technique for healthy subjects and a symptomatic knee cartilage degenerated subject. The effect of the acquired CEST saturation frequency offset step-size was investigated to establish the optimal step-size to obtain reproducible gagCEST maps. Our novel 3D gagCEST technique demonstrates markedly higher gagCEST contrast value than the previously reported 3D gagCEST studies. This study demonstrates the need for separate B0 and B1 inhomogeneity estimation and correction. CONCLUSION The new technique provided high quality gagCEST maps with clearer visualization of different layers of knee cartilage with reproducible results. Magn Reson Med 77:1866-1873, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
| | | | - Puneet Bagga
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hari Hariharan
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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25
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Haris M, Singh A, Reddy S, Bagga P, Kneeland JB, Tjoumakaris FP, Hariharan H, Marincola FM, Reddy R. Characterization of viscosupplementation formulations using chemical exchange saturation transfer (ViscoCEST). J Transl Med 2016; 14:92. [PMID: 27071650 PMCID: PMC4830049 DOI: 10.1186/s12967-016-0850-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [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] [Received: 12/03/2015] [Accepted: 03/31/2016] [Indexed: 01/10/2023] Open
Abstract
Background Osteoarthritis (OA) is characterized by progressive loss of cartilage in joints, and is a major cause of pain and disability, and imposes significant health care expense. New therapies are being developed to treat the symptomatic effect of OA, one of which is intra-articular injection of viscosupplementations of different forms of hyaluronic acid (HA). The current study evaluates the chemical exchange saturation transfer (CEST) effect from two popular viscosupplementations [Hylan gf-20 (Synvisc) and hyaluronan (Orthovisc)] by targeting the exchangeable hydroxyl protons present on these molecules (ViscoCEST). Methods ViscoCEST imaging from two viscosupplementations (Synvisc and Orthovisc) was performed on a 7T Siemens whole body MRI scanner. ViscoCEST images were collected with different combination of saturation pulse power and saturation duration. Z spectra were acquired at B1rms of 3.6 μT and 1 s saturation duration by varying the frequency from −4 to +4 ppm in step size of 0.1 ppm. Field inhomogeneity (B0) and radiofrequency (B1) maps were also acquired to correct ViscoCEST contrast map for any inhomogeneity. Results Both viscosupplementations showed broad CEST effect (ViscoCEST), which peaked ~0.8 ppm from down field of water resonance. Orthovisc showed 20 % higher ViscoCEST contrast than Synvisc suggestive of more HA component in Orthovisc. Increased ViscoCEST contrast was observed from both viscosupplementations with increase in B1rms and saturation pulse duration. Conclusion ViscoCEST has a potential to image the spatial distribution of viscosupplements in vivo in patients’ intra-articular space as well as temporal variation in their spatial distribution.
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Affiliation(s)
- Mohammad Haris
- Research Branch, Sidra Medical and Research Center, 26999, Doha, Qatar. .,Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA.
| | - Anup Singh
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA.,Center for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Sanjana Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA
| | - Puneet Bagga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA
| | - J Bruce Kneeland
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, PA, USA
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26
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DeBrosse C, Nanga RPR, Bagga P, Nath K, Haris M, Marincola F, Schnall MD, Hariharan H, Reddy R. Lactate Chemical Exchange Saturation Transfer (LATEST) Imaging in vivo A Biomarker for LDH Activity. Sci Rep 2016; 6:19517. [PMID: 26794265 PMCID: PMC4726389 DOI: 10.1038/srep19517] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/09/2015] [Indexed: 01/18/2023] Open
Abstract
Non-invasive imaging of lactate is of enormous significance in cancer and metabolic disorders where glycolysis dominates. Here, for the first time, we describe a chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) method (LATEST), based on the exchange between lactate hydroxyl proton and bulk water protons to image lactate with high spatial resolution. We demonstrate the feasibility of imaging lactate with LATEST in lactate phantoms under physiological conditions, in a mouse model of lymphoma tumors, and in skeletal muscle of healthy human subjects pre- and post-exercise. The method is validated by measuring LATEST changes in lymphoma tumors pre- and post-infusion of pyruvate and correlating them with lactate determined from multiple quantum filtered proton magnetic resonance spectroscopy (SEL-MQC 1H-MRS). Similarly, dynamic LATEST changes in exercising human skeletal muscle are correlated with lactate determined from SEL-MQC 1H-MRS. The LATEST method does not involve injection of radioactive isotopes or labeled metabolites. It has over two orders of magnitude higher sensitivity compared to conventional 1H-MRS. It is anticipated that this technique will have a wide range of applications including diagnosis and evaluation of therapeutic response of cancer, diabetes, cardiac, and musculoskeletal diseases. The advantages of LATEST over existing methods and its potential challenges are discussed.
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Affiliation(s)
- Catherine DeBrosse
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Puneet Bagga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Kavindra Nath
- Laboratory of Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Mohammad Haris
- Research Branch, Sidra Medical and Research Center, Doha, Qatar
| | | | - Mitchell D Schnall
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
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Hariharan H, Tiwari KP, Kumthekar S, Thomas D, Hegamin-Younger C, Edwards B, Sharma RN. Serological Detection of Caseous Lymphadenitis in Sheep and Goats Using a Commercial ELISA in Grenada, West Indies. ACTA ACUST UNITED AC 2015. [DOI: 10.5171/2015.473459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Singh A, Reddy D, Haris M, Cai K, Rajender Reddy K, Hariharan H, Reddy R. T1ρ MRI of healthy and fibrotic human livers at 1.5 T. J Transl Med 2015; 13:292. [PMID: 26350896 PMCID: PMC4562204 DOI: 10.1186/s12967-015-0648-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [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] [Received: 06/13/2015] [Accepted: 08/21/2015] [Indexed: 01/06/2023] Open
Abstract
Background Liver fibrosis is a public health problem worldwide. There is a need of noninvasive imaging based methods for better diagnosis of this disease. In the current study, we aim to evaluate the potential of T1ρ MRI technique in detecting and characterizing different grades of liver fibrosis in vivo in humans. Methods Healthy subjects and patients with liver fibrosis were prospectively recruited for T1ρ MRI of liver on a 1.5 T MR scanner. Single slice T1ρ weighted images were acquired at different spin lock duration (0, 10, 20 and 30 ms) with spin lock amplitude of 500 Hz in a single breath-hold. Additionally, liver’s T1ρ images were acquired from five healthy subjects on the same day (n = 2) and different day (n = 2) sessions for test–retest study. Liver biopsy samples from patients were obtained and used to calculate the METAVIR score to define the stage of fibrosis and inflammation grade. T1ρ maps were generated followed by computation of mean and standard deviation (SD) values. Coefficient of variation (COV) of T1ρ values between two MRI scans was computed to determine reproducibility in liver. T test was used to compare T1ρ values between healthy and fibrotic liver. Pearson correlation was performed between stages of liver fibrosis and T1ρ values. Results The mean (SD) T1ρ value among subject with healthy liver was 51.04 (3.06) ms. The COV of T1ρ values between two repetitions in the same day session was 0.83 ± 0.8 % and in different day session was 5.4 ± 2.7 %. T1ρ values in fibrotic liver were significantly higher compared to those of healthy liver (p < 0.05). A statically significant correlation between stages of fibrosis and T1ρ values was observed (r = 0.99, p < 0.05). Inflammation score for one patient was 2 and for remaining patients it was 1. Conclusions Proposed T1ρ pulse sequence design and protocol enabled acquisition of a single slice T1ρ weighted images in a single breath-hold and hence mitigated breathing motion related artifacts. Preliminary results have shown the sensitivity of T1ρ values to changes induced by liver fibrosis, and may potentially be used as a clinical biomarker to delineate the stages of liver fibrosis. Further, studies on a large number of subjects are required to validate the observations of the current study. Nevertheless, T1ρ imaging can be easily setup on a clinical scanner to monitor the progression of liver fibrosis and to the evaluate efficacy of anti-fibrotic drugs.
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Affiliation(s)
- Anup Singh
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA. .,Center for Biomedical Engineering, Indian Institute of Technology Delhi, Block-II, Room No. 389, Hauz Khas, Delhi, 110016, India.
| | - Damodar Reddy
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
| | - Mohammad Haris
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA.,Research Branch, Sidra Medical and Research Center, Doha, Qatar
| | - Kejia Cai
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA.,Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
| | - K Rajender Reddy
- Division of Gastroenterology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
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Cai K, Singh A, Poptani H, Li W, Yang S, Lu Y, Hariharan H, Zhou XJ, Reddy R. CEST signal at 2ppm (CEST@2ppm) from Z-spectral fitting correlates with creatine distribution in brain tumor. NMR Biomed 2015; 28:1-8. [PMID: 25295758 PMCID: PMC4257884 DOI: 10.1002/nbm.3216] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 08/14/2014] [Accepted: 08/17/2014] [Indexed: 05/03/2023]
Abstract
In general, multiple components such as water direct saturation, magnetization transfer (MT), chemical exchange saturation transfer (CEST) and aliphatic nuclear Overhauser effect (NOE) contribute to the Z-spectrum. The conventional CEST quantification method based on asymmetrical analysis may lead to quantification errors due to the semi-solid MT asymmetry and the aliphatic NOE located on a single side of the Z-spectrum. Fitting individual contributors to the Z-spectrum may improve the quantification of each component. In this study, we aim to characterize the multiple exchangeable components from an intracranial tumor model using a simplified Z-spectral fitting method. In this method, the Z-spectrum acquired at low saturation RF amplitude (50 Hz) was modeled as the summation of five Lorentzian functions that correspond to NOE, MT effect, bulk water, amide proton transfer (APT) effect and a CEST peak located at +2 ppm, called CEST@2ppm. With the pixel-wise fitting, the regional variations of these five components in the brain tumor and the normal brain tissue were quantified and summarized. Increased APT effect, decreased NOE and reduced CEST@2ppm were observed in the brain tumor compared with the normal brain tissue. Additionally, CEST@2ppm decreased with tumor progression. CEST@2ppm was found to correlate with the creatine concentration quantified with proton MRS. Based on the correlation curve, the creatine contribution to CEST@2ppm was quantified. The CEST@2ppm signal could be a novel imaging surrogate for in vivo creatine, the important bioenergetics marker. Given its noninvasive nature, this CEST MRI method may have broad applications in cancer bioenergetics.
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Affiliation(s)
- Kejia Cai
- Department of Radiology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Anup Singh
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Harish Poptani
- Molecular Imaging Labs, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Weiguo Li
- Research Resource Center, Department of Bioengineering, University of Illinois College of Medicine, Chicago, IL, USA
- Department of Radiology, Northwestern University, Chicago, IL, USA
| | - Shaolin Yang
- Department of Psychiatry and Radiology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Yang Lu
- Department of Radiology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Xiaohong J. Zhou
- Department of Radiology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Haris M, Singh A, Cai K, Nath K, Verma G, Nanga RPR, Hariharan H, Detre JA, Epperson N, Reddy R. High resolution mapping of modafinil induced changes in glutamate level in rat brain. PLoS One 2014; 9:e103154. [PMID: 25068408 PMCID: PMC4113382 DOI: 10.1371/journal.pone.0103154] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/24/2014] [Indexed: 11/19/2022] Open
Abstract
Modafinil is marketed in the United States for the treatment of narcolepsy and daytime somnolence due to shift-work or sleep apnea. Investigations of this drug in the treatment of cocaine and nicotine dependence in addition to disorders of executive function are also underway. Modafinil has been known to increase glutamate levels in rat brain models. Proton magnetic resonance spectroscopy (1HMRS) has been commonly used to detect the glutamate (Glu) changes in vivo. In this study, we used a recently described glutamate chemical exchange saturation transfer (GluCEST) imaging technique to measure Modafinil induced regional Glu changes in rat brain and compared the results with Glu concentration measured by single voxel 1HMRS. No increases in either GluCEST maps or 1HMRS were observed after Modafinil injection over a period of 5 hours. However, a significant increase in GluCEST (19 ± 4.4%) was observed 24 hours post Modafinil administration, which is consistent with results from previous biochemical studies. This change was not consistently seen with 1HMRS. GluCEST mapping allows regional cerebral Glu changes to be measured and may provide a useful clinical biomarker of Modafinil effects for the management of patients with sleep disorders and addiction.
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Affiliation(s)
- Mohammad Haris
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Research Branch, Sidra Medical and Research Center, Doha, Qatar
- * E-mail:
| | - Anup Singh
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Center for Biomedical Engineering, Indian Institute of Technology Delhi, Delhi, India
| | - Kejia Cai
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- CMRR, Radiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Kavindra Nath
- Molecular Imaging, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gaurav Verma
- Molecular Imaging, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ravi Prakash Reddy Nanga
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hari Hariharan
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - John A. Detre
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Neill Epperson
- Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ravinder Reddy
- CMROI, Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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31
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Crescenzi R, DeBrosse C, Nanga RPR, Reddy S, Haris M, Hariharan H, Iba M, Lee VMY, Detre JA, Borthakur A, Reddy R. In vivo measurement of glutamate loss is associated with synapse loss in a mouse model of tauopathy. Neuroimage 2014; 101:185-92. [PMID: 25003815 DOI: 10.1016/j.neuroimage.2014.06.067] [Citation(s) in RCA: 53] [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: 03/26/2014] [Revised: 06/05/2014] [Accepted: 06/28/2014] [Indexed: 11/17/2022] Open
Abstract
Glutamate is the primary excitatory neurotransmitter in the brain, and is implicated in neurodegenerative diseases such as Alzheimer's disease (AD) and several other tauopathies. The current method for measuring glutamate in vivo is proton magnetic resonance spectroscopy ((1)H MRS), although it has poor spatial resolution and weak sensitivity to glutamate changes. In this study, we sought to measure the effect of tau pathology on glutamate levels throughout the brain of a mouse model of tauopathy using a novel magnetic resonance imaging (MRI) technique. We employed glutamate chemical exchange saturation transfer (GluCEST) imaging, which has been previously validated as a complimentary method for measuring glutamate levels with several important advantages over conventional (1)H MRS. We hypothesized that the regional changes in glutamate levels would correlate with histological measurements of pathology including pathological tau, synapse and neuron loss. Imaging and spectroscopy were carried out on tau transgenic mice with the P301S mutation (PS19, n=9) and their wild-type littermates (WT, n=8), followed by immunohistochemistry of their brain tissue. GluCEST imaging resolution allowed for sub-hippocampal analysis of glutamate. Glutamate was significantly decreased by 29% in the CA sub-region of the PS19 hippocampus, and by 15% in the thalamus, where synapse loss was also measured. Glutamate levels and synapse density remained high in the dentate gyrus sub-region of the hippocampus, where neurogenesis is known to occur. The further development of GluCEST imaging for preclinical applications will be valuable, as therapies are being tested in mouse models of tauopathy.
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Affiliation(s)
- Rachelle Crescenzi
- Department of Biochemistry and Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA; Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
| | - Catherine DeBrosse
- Department of Biochemistry and Molecular Biophysics (BMB), University of Pennsylvania, Philadelphia, PA, USA; Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sanjana Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Mohammed Haris
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michiyo Iba
- Center for Neurodegenerative Disease Research (CNDR), Department of Pathology & Lab Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Virginia M Y Lee
- Center for Neurodegenerative Disease Research (CNDR), Department of Pathology & Lab Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Center for Functional Neuroimaging (CFN), Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Arijitt Borthakur
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Herbers M, Hariharan H, Matthew V, Oliveira S, Rovira A, Sharma RN, Ferguson HW. Photobacterium damselae in bigeye scad, Selar crumenophthalmus (Bloch), from Grenada, West Indies. J Fish Dis 2014; 37:675-677. [PMID: 23865935 DOI: 10.1111/jfd.12149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 05/28/2013] [Accepted: 05/28/2013] [Indexed: 06/02/2023]
Affiliation(s)
- M Herbers
- Pathobiology Academic Programme, School of Veterinary Medicine, St. George's University, Grenada, West Indies; Marine Medicine Programme, School of Veterinary Medicine, St George's University, Grenada, West Indies
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Xu HN, Kadlececk S, Pullinger B, Profka H, Cai K, Hariharan H, Rizi R, Li LZ. In vivo metabolic evaluation of breast tumor mouse xenografts for predicting aggressiveness using the hyperpolarized (13)C-NMR technique. Adv Exp Med Biol 2014; 789:237-242. [PMID: 23852500 DOI: 10.1007/978-1-4614-7411-1_32] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In vivo imaging/spectroscopic biomarkers for solid tumor aggressiveness are needed in the clinic to facilitate cancer diagnosis and treatment strategies. In mouse models of human melanoma and breast cancer, we were able to detect the metabolic differences among tumors of different metastatic potential and between normal and cancer tissues by optical imaging of the mitochondrial redox state of snap-frozen tissue samples. Such metabolic differences indicate that tumors of different aggressiveness have different metabolic homeostasis, which supports that kinetic parameters such as rate constant(s) can also serve as biomarkers for cancer aggressiveness and treatment response. Here we present our preliminary study on the mouse xenografts of the aggressive and indolent human breast cancer cell lines using the hyperpolarized (13)C-NMR (HP-NMR) technique. By recording the time courses of (13)C-pyruvate tracer and its metabolite signals in vivo, particularly the (13)C-lactate signal, the apparent rate constants of both the forward and reverse reactions catalyzed by lactate dehydrogenase (LDH) were extracted via the ratiometric modeling of the two-site exchange reaction that we developed. Data from four breast tumors (MCF-7, MDA-MB-468, and MDA-MB-231 medium and large) with different aggressiveness are included. We demonstrate the feasibility to quantify the apparent rate constants of LDH reactions in breast tumor xenografts.
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Affiliation(s)
- He N Xu
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Britton Chance Laboratory of Redox Imaging, Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen Kadlececk
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ben Pullinger
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Harrila Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kejia Cai
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lin Z Li
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
- Britton Chance Laboratory of Redox Imaging, Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA.
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA.
- Institute of Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA.
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Kogan F, Haris M, Singh A, Cai K, Debrosse C, Nanga RPR, Hariharan H, Reddy R. Method for high-resolution imaging of creatine in vivo using chemical exchange saturation transfer. Magn Reson Med 2014. [PMID: 23412909 DOI: 10.1002/mrm.246415] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
PURPOSE To develop a chemical exchange saturation transfer (CEST)-based technique to measure free creatine (Cr) and to validate the technique by measuring the distribution of Cr in muscle with high spatial resolution before and after exercise. METHODS Phantom studies were performed to determine contributions from other Cr kinase metabolites to the CEST effect from Cr (CrCEST). CEST, T2 , magnetization transfer ratio and (31) P magnetic resonance spectroscopy acquisitions of the lower leg were performed before and after plantar flexion exercise on a 7T whole-body magnetic resonance scanner on healthy volunteers. RESULTS Phantom studies demonstrated that while Cr exhibited significant CEST effect there were no appreciable contributions from other metabolites. In healthy human subjects, following mild plantar flexion exercise, increases in the CEST effect from Cr were observed, which recovered exponentially back to baseline. This technique exhibited good spatial resolution and was able to differentiate differences in muscle utilization among subjects. The CEST effect from Cr results were compared with (31) P magnetic resonance spectroscopy results showing good agreement in the Cr and phosphocreatine recovery kinetics. CONCLUSION Demonstrated a CEST-based technique to measure free Cr changes in in vivo muscle. The CEST effect from Cr imaging can spatially map changes in Cr concentration in muscle following mild exercise. This may serve as a tool for the diagnosis and treatment of various disorders affecting muscle.
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Affiliation(s)
- Feliks Kogan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, Pennsylvania, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Sylvester WRB, Amadi V, Pinckney R, Macpherson CNL, McKibben JS, Bruhl-Day R, Johnson R, Hariharan H. Prevalence, serovars and antimicrobial susceptibility of Salmonella spp. from wild and domestic green iguanas (Iguana iguana) in Grenada, West Indies. Zoonoses Public Health 2013; 61:436-41. [PMID: 24325463 DOI: 10.1111/zph.12093] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [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: 09/17/2013] [Indexed: 11/27/2022]
Abstract
Cloacal swabs from 62 green iguanas (Iguana iguana), including 47 wild and 15 domestic ones from five parishes of Grenada, were sampled during a 4-month period of January to April 2013 and examined by enrichment and selective culture for the presence of Salmonella spp. Fifty-five per cent of the animals were positive, and eight serovars of Salmonella were isolated. The most common serovar was Rubislaw (58.8%), a serovar found recently in many cane toads in Grenada, followed by Oranienburg (14.7%), a serovar that has been causing serious human disease outbreaks in Japan. Serovar IV:48:g,z51 :- (formerly, S. Marina) highly invasive and known for serious infections in children in the United States, constituted 11.8% of the isolates, all of them being from domestic green iguanas. Salmonella Newport, a serovar recently found in a blue land crab in Grenada, comprised 11.8% of the isolates from the green iguanas. The remaining four less frequent serovars included S. Javiana and S. Glostrup. Antimicrobial susceptibility tests conducted by a disc diffusion method against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal, with intermediate susceptibility, mainly to streptomycin, tetracycline and cefotaxime. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars from wild and domestic green iguanas in Grenada, West Indies.
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Affiliation(s)
- W R B Sylvester
- Small Animal Medicine and Surgery Academic Program, School of Veterinary Medicine, St. George's University, St. George's, Grenada, West Indies
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Verma G, Hariharan H, Nagarajan R, Nanga RPR, Delikatny EJ, Albert Thomas M, Poptani H. Implementation of two-dimensional L-COSY at 7 Tesla: an investigation of reproducibility in human brain. J Magn Reson Imaging 2013; 40:1319-27. [PMID: 24273136 DOI: 10.1002/jmri.24510] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [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: 07/29/2013] [Accepted: 10/09/2013] [Indexed: 12/23/2022] Open
Abstract
PURPOSE To evaluate the utility of two-dimensional (2D) Localized Correlated Spectroscopy (L-COSY) in metabolic profiling of the human brain at 7 Tesla (T). MATERIALS AND METHODS The 2D L-COSY sequence was implemented at 7 T and its reliability was assessed by test-retest studies of a metabolite phantom and a healthy volunteer. L-COSY data were acquired from the occipital lobe of healthy subjects (n = 6; all male; age, 30-72 years) to assess intersubject variability. Additionally, two subjects underwent scans from the parieto-occipital region, basal ganglia, frontal lobe or dorsolateral prefrontal cortex to test the versatility of L-COSY in studying differing anatomy. Integral/volume measurements of L-COSY spectra were used to estimate normalized metabolite-to-creatine concentrations. RESULTS Phantom test-retest studies revealed coefficients of variation (CVs) of 3-20% for most metabolites. Human 2D L-COSY spectra permitted detection of several metabolite resonances from multiple locations and inter-subject variation studies demonstrated CVs of 4-26%. Cross-peaks from gamma-aminobutyric acid (GABA), isoleucine (Ile), lysine (Lys) and Ethanolamine (Eth) were quantified, which are not readily resolvable with conventional one-dimensional (1D) MR spectroscopy. CONCLUSION 2D L-COSY at 7 T demonstrated improved sensitivity in detecting additional metabolites with reliability comparable to established techniques at lower fields, which may aid in the metabolic assessment of diseased states.
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Affiliation(s)
- Gaurav Verma
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Kogan F, Haris M, Debrosse C, Singh A, Nanga RP, Cai K, Hariharan H, Reddy R. In vivo chemical exchange saturation transfer imaging of creatine (CrCEST) in skeletal muscle at 3T. J Magn Reson Imaging 2013; 40:596-602. [PMID: 24925857 DOI: 10.1002/jmri.24412] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [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: 05/21/2013] [Accepted: 08/21/2013] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To characterize the chemical exchange saturation transfer (CEST)-based technique to measure free creatine (Cr), a key component of muscle energy metabolism, distribution in skeletal muscle with high spatial resolution before and after exercise at 3T. MATERIALS AND METHODS CrCEST saturation parameters were empirically optimized for 3T. CEST, T2 , magnetization transfer ratio (MTR), and (31) P magnetic resonance spectroscopy (MRS) acquisitions of the lower leg were performed before and after mild plantar flexion exercise on a 3T whole-body MR scanner on six healthy volunteers. RESULTS The feasibility of imaging Cr changes in skeletal muscle following plantar flexion exercise using CrCEST was demonstrated at 3T. This technique exhibited good spatial resolution and was able to differentiate differences in muscle use among subjects. The CrCEST results were compared with (31) P MRS results, showing good agreement in the Cr and PCr recovery kinetics. A relationship of 0.45% CrCESTasym /mM Cr was observed across all subjects. CONCLUSION It is demonstrated that the CrCEST technique could be applied at 3T to measure dynamic changes in creatine in muscle in vivo. The widespread availability and clinical applicability of 3T scanners has the potential to clinically advance this method.
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Affiliation(s)
- Feliks Kogan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Cai K, Singh A, Roalf DR, Nanga RPR, Haris M, Hariharan H, Gur R, Reddy R. Mapping glutamate in subcortical brain structures using high-resolution GluCEST MRI. NMR Biomed 2013; 26:1278-84. [PMID: 23553932 PMCID: PMC3999922 DOI: 10.1002/nbm.2949] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [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: 07/09/2012] [Revised: 02/21/2013] [Accepted: 02/22/2013] [Indexed: 05/19/2023]
Abstract
In vivo measurement of glutamate (Glu) in brain subcortex can elucidate the role these structures play in cognition and neuropsychiatric disorders. However, accurate quantification of Glu in subcortical regions is challenging. Recently, a novel MRI method based on the Glu chemical exchange saturation transfer (GluCEST) effect has been developed for detecting brain Glu in millimolar concentrations. Here, we use GluCEST to map Glu distributions in subcortical structures of the human brain (e.g. amygdala, hippocampus). Overall, GluCEST was ~40% higher in gray matter than in white matter. Within the subcortical gray matters, amygdala showed the highest GluCEST contrast. Utilizing MR spectroscopic data, in vivo GluCEST detection sensitivity (~0.8% mM(-1) ) in subcortical gray matter was evaluated and was consistent with the previously reported values. In general, the GluCEST map approximates the Glu receptor distribution reported in previous positron emission tomography (PET) studies. These findings suggest that high-resolution GluCEST MRI of subcortical brain structures may prove to be a useful tool in diagnosis of brain disorders or treatment responses.
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Affiliation(s)
- Kejia Cai
- University of Pennsylvania, Radiology, Philadelphia, Pennsylvania, United States
| | - Anup Singh
- University of Pennsylvania, Radiology, Philadelphia, Pennsylvania, United States,
| | - David R Roalf
- University of Pennsylvania, Psychiatry, Philadelphia, Pennsylvania, United States,
| | | | - Mohammad Haris
- University of Pennsylvania, Radiology, Philadelphia, Pennsylvania, United States,
| | - Hari Hariharan
- University of Pennsylvania, Radiology, Philadelphia, Pennsylvania, United State,
| | - Ruben Gur
- University of Pennsylvania, Psychiatry, Philadelphia, Pennsylvania, United States,
| | - Ravinder Reddy
- University of Pennsylvania, Radiology, Philadelphia, Pennsylvania, United States,
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Chikweto A, Tiwari K, Kumthekar S, Stone D, Louison B, Thomas D, Sharma R, Hariharan H. Serologic detection of antibodies to Brucella spp. using a commercial ELISA in cattle in Grenada, West Indies. Trop Biomed 2013; 30:277-280. [PMID: 23959493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bovine brucellosis, caused mainly by Brucella abortus, a zoonotic bacterium, has been reported from many areas of the world, including Central and South America, and the Caribbean island state of Trinidad and Tobago. Although brucellosis has been eradicated from domestic cattle in Canada it still exists in one or two herds in the United States. Serological tests are important in estimating prevalence of Brucella exposure in order to target eradication programmes. In this study, serum samples from 150 cattle were tested using a commercial competitive enzyme linked immunosorbent assay (SVANOVIR®Brucella-Ab C-ELISA) which detects antibodies to both B. abortus and Brucella melitensis. All cattle tested were greater than 6 months old and were unvaccinated. Sampled cattle were from 35 herds representing animals from all 6 parishes of Grenada. Nine of the 150 animals (6%) were positive for antibodies to B. abortus and/or melitensis by the C-ELISA. Of the 35 herds, 7 (20%) had C-ELISA- positive animals. Three of the 6 parishes contained positive herds. Based on the high sensitivity (98%) and specificity (99.7%) of the C-ELISA, these results strongly indicate the presence of cattle exposed to B. abortus and/or melitensis in Grenada.
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Affiliation(s)
- A Chikweto
- Pathobiology Academic Program, School of Veterinary Medicine, P.O Box 7, St. George's University, St. George's, Grenada, West Indies
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Abstract
Chemical exchange saturation transfer (CEST) is a magnetic resonance imaging (MRI) contrast enhancement technique that enables indirect detection of metabolites with exchangeable protons. Endogenous metabolites with exchangeable protons including many endogenous proteins with amide protons, glycosaminoglycans (GAG), glycogen, myo-inositol (MI), glutamate (Glu), creatine (Cr) and several others have been identified as potential in vivo endogenous CEST agents. These endogenous CEST agents can be exploited as non-invasive and non-ionizing biomarkers of disease diagnosis and treatment monitoring. This review focuses on the recent technical developments in endogenous in vivo CEST MRI from various metabolites as well as their potential clinical applications. The basic underlying principles of CEST, its potential limitations and new techniques to mitigate them are discussed.
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Affiliation(s)
- Feliks Kogan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104
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Haris M, Nath K, Cai K, Singh A, Crescenzi R, Kogan F, Verma G, Reddy S, Hariharan H, Melhem ER, Reddy R. Imaging of glutamate neurotransmitter alterations in Alzheimer's disease. NMR Biomed 2013; 26:386-91. [PMID: 23045158 PMCID: PMC3556355 DOI: 10.1002/nbm.2875] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [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: 02/16/2012] [Revised: 08/27/2012] [Accepted: 08/29/2012] [Indexed: 05/03/2023]
Abstract
Glutamate (Glu) is a major excitatory neurotransmitter in the brain and has been shown to decrease in the early stages of Alzheimer's disease (AD). Using a glutamate chemical (amine) exchange saturation transfer (GluCEST) method, we imaged the change in [Glu] in the APP-PS1 transgenic mouse model of AD at high spatial resolution. Compared with wild-type controls, AD mice exhibited a notable reduction in GluCEST contrast (~30%) in all areas of the brain. The change in [Glu] was further validated through (1) H MRS. A positive correlation was observed between GluCEST contrast and (1) H MRS-measured Glu/total creatine ratio. This method potentially provides a novel noninvasive biomarker for the diagnosis of the disease in preclinical stages and enables the development of disease-modifying therapies for AD.
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Affiliation(s)
- Mohammad Haris
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kavindra Nath
- Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Kejia Cai
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Anup Singh
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rachelle Crescenzi
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Feliks Kogan
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Gaurav Verma
- Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Sanjana Reddy
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Elias R. Melhem
- Neuroradiology, Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Ravinder Reddy
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Kogan F, Haris M, Singh A, Cai K, Debrosse C, Nanga RPR, Hariharan H, Reddy R. Method for high-resolution imaging of creatine in vivo using chemical exchange saturation transfer. Magn Reson Med 2013; 71:164-72. [PMID: 23412909 DOI: 10.1002/mrm.24641] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [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: 11/05/2012] [Revised: 12/07/2012] [Accepted: 12/26/2012] [Indexed: 01/15/2023]
Abstract
PURPOSE To develop a chemical exchange saturation transfer (CEST)-based technique to measure free creatine (Cr) and to validate the technique by measuring the distribution of Cr in muscle with high spatial resolution before and after exercise. METHODS Phantom studies were performed to determine contributions from other Cr kinase metabolites to the CEST effect from Cr (CrCEST). CEST, T2 , magnetization transfer ratio and (31) P magnetic resonance spectroscopy acquisitions of the lower leg were performed before and after plantar flexion exercise on a 7T whole-body magnetic resonance scanner on healthy volunteers. RESULTS Phantom studies demonstrated that while Cr exhibited significant CEST effect there were no appreciable contributions from other metabolites. In healthy human subjects, following mild plantar flexion exercise, increases in the CEST effect from Cr were observed, which recovered exponentially back to baseline. This technique exhibited good spatial resolution and was able to differentiate differences in muscle utilization among subjects. The CEST effect from Cr results were compared with (31) P magnetic resonance spectroscopy results showing good agreement in the Cr and phosphocreatine recovery kinetics. CONCLUSION Demonstrated a CEST-based technique to measure free Cr changes in in vivo muscle. The CEST effect from Cr imaging can spatially map changes in Cr concentration in muscle following mild exercise. This may serve as a tool for the diagnosis and treatment of various disorders affecting muscle.
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Affiliation(s)
- Feliks Kogan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, Pennsylvania, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Cai K, Nanga RPR, Lamprou L, Schinstine C, Elliott M, Hariharan H, Reddy R, Epperson CN. The impact of gabapentin administration on brain GABA and glutamate concentrations: a 7T ¹H-MRS study. Neuropsychopharmacology 2012; 37:2764-71. [PMID: 22871916 PMCID: PMC3499716 DOI: 10.1038/npp.2012.142] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Gamma-aminobutyric acid (GABA) and glutamate are implicated in numerous neuropsychiatric and substance abuse conditions, but their spectral overlap with other resonances makes them a challenge to quantify in humans. Gabapentin, marketed for the treatment of seizures and neuropathic pain, has been shown to increase in vivo GABA concentration in the brain of both rodents and humans. Gabapentin effects on glutamate are not known. We conducted a gabapentin (900 mg) challenge in healthy human subjects to confirm and explore its effects on GABA and glutamate concentrations, respectively, and to test the ability of single voxel localized proton magnetic resonance spectroscopy (¹H-MRS) to reliably measure GABA and glutamate in the visual cortex at the ultra-high magnetic field of 7 Tesla. Reproducibility of GABA and glutamate measurements was determined in a comparison group without drug twice within day and 2 weeks apart. Although GABA concentration changes were small both within day (average 5.6%) and between day (average 4.8%), gabapentin administration was associated with an average increase in GABA concentration of 55.7% (6.9-91.0%). Importantly, drug-induced change in GABA levels was inversely correlated to the individual's baseline GABA level (R²=0.72). Mean glutamate concentrations did not change significantly with or without drug administration. In conclusion, localized ¹H-MRS at 7 Tesla can be successfully applied to the measurement of GABA concentration and is sensitive to acute drug-induced changes in cortical GABA. Whether baseline GABA concentrations predict clinical efficacy of gabapentin is an area worthy of exploration.
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Affiliation(s)
- Kejia Cai
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi PR Nanga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa Lamprou
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Claudia Schinstine
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Elliott
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - C Neill Epperson
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Penn Center for Women's Behavioral Wellness, 3535 Market Street, Room 3001, Philadelphia, PA 19104, USA, Tel: +1 215 573-8871, Fax: +1 215 573 8881, E-mail:
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Haris M, Nanga RPR, Singh A, Cai K, Kogan F, Hariharan H, Reddy R. Exchange rates of creatine kinase metabolites: feasibility of imaging creatine by chemical exchange saturation transfer MRI. NMR Biomed 2012; 25:1305-9. [PMID: 22431193 PMCID: PMC3837460 DOI: 10.1002/nbm.2792] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [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: 12/07/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 05/04/2023]
Abstract
Creatine (Cr), phosphocreatine (PCr) and adenosine-5-triphosphate (ATP) are major metabolites of the enzyme creatine kinase (CK). The exchange rate of amine protons of CK metabolites at physiological conditions has been limited. In the current study, the exchange rate and logarithmic dissociation constant (pKa) of amine protons of CK metabolites were calculated. Further, the chemical exchange saturation transfer effect (CEST) of amine protons of CK metabolites with bulk water was explored. At physiological temperature and pH, the exchange rate of amine protons in Cr was found to be 7-8 times higher than PCr and ATP. A higher exchange rate in Cr was associated with lower pKa value, suggesting faster dissociation of its amine protons compared to PCr and ATP. CEST MR imaging of these metabolites in vitro in phantoms displayed predominant CEST contrast from Cr and negligible contribution from PCr and ATP with the saturation pulse parameters used in the current study. These results provide a new method to perform high-resolution proton imaging of Cr without contamination from PCr. Potential applications of these finding are discussed.
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Affiliation(s)
- Mohammad Haris
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104-6100, USA. ,
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Drake M, Amadi V, Zieger U, Johnson R, Hariharan H. Prevalence of Salmonella spp. in cane toads (Bufo marinus) from Grenada, West Indies, and their antimicrobial susceptibility. Zoonoses Public Health 2012; 60:437-41. [PMID: 23035820 DOI: 10.1111/zph.12018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cloacal swabs and caecal contents sampled from 58 cane toads (Bufo marinus) in St George's parish, Grenada, during a 7-month period in 2011 were examined by an enrichment and selective culture method for presence of Salmonella spp. Twenty-four (41%) toads were positive for Salmonella spp. of which eight were Salmonella enterica serovar Javiana, and eight were S. enterica serovar Rubislaw. The other serovars were as follows: Montevideo, 6; Arechavaleta, 1; and serovar: IV:43:-:-, 1. The high frequency of isolation of serovar Javiana, an emerging human pathogen associated with several outbreaks in the recent years in the eastern United States, suggests a possible role for cane toads in transmission of this serovar. Although S. Rubislaw has been isolated from lizards, bats and cases of some human infections, there is no report of its carriage by cane toads, and in such high frequency. The rate of carriage of S. Montevideo, a cause for human foodborne outbreaks around the world was also over 10% in the 58 toads sampled in this study. The antimicrobial drug susceptibility tests against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, imipenem, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal and is of little concern. Antimicrobial resistance was limited to ampicillin and amoxicillin-clavulanic acid in one isolate of S. Javiana and one isolate of S. Rubislaw. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars not identified previously in cane toads in Grenada, West Indies.
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Affiliation(s)
- M Drake
- School of Veterinary Medicine, St George's University, West Indies,Grenada
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Haris M, Singh A, Cai K, Nath K, Crescenzi R, Kogan F, Hariharan H, Reddy R. MICEST: a potential tool for non-invasive detection of molecular changes in Alzheimer's disease. J Neurosci Methods 2012; 212:87-93. [PMID: 23041110 DOI: 10.1016/j.jneumeth.2012.09.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 09/08/2012] [Accepted: 09/22/2012] [Indexed: 11/26/2022]
Abstract
Myo-inositol (mIns) is a marker of glial cells proliferation and has been shown to increase in early Alzheimer's disease (AD) pathology. mIns exhibits a concentration dependent chemical-exchange-saturation-transfer (CEST) effect (MICEST) between its hydroxyl groups and bulk water protons. Using the endogenous MICEST technique brain mIns concentration and glial cells proliferation can be mapped at high spatial resolution. The high resolution mapping of mIns was performed using MICEST technique on ∼20 months old APP-PS1 transgenic mouse model of AD as well as on age matched wild type (WT) control (n=5). The APP-PS1 mice show ∼50% higher MICEST contrast than WT control with concomitant increase in mIns concentration as measured through proton spectroscopy. Immunostaining against glial-fibric-acidic protein also depicts proliferative glial cells in larger extent in APP-PS1 than WT mice, which correspond to the higher mIns concentration. Potential significance of MICEST in early detection of AD pathology is discussed in detail.
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Affiliation(s)
- Mohammad Haris
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, USA.
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Kogan F, Singh A, Cai K, Haris M, Hariharan H, Reddy R. Investigation of chemical exchange at intermediate exchange rates using a combination of chemical exchange saturation transfer (CEST) and spin-locking methods (CESTrho). Magn Reson Med 2012; 68:107-19. [PMID: 22009759 PMCID: PMC3564676 DOI: 10.1002/mrm.23213] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [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: 02/16/2011] [Revised: 07/25/2011] [Accepted: 08/18/2011] [Indexed: 11/08/2022]
Abstract
Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer and T(1)(ρ) magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime.
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Affiliation(s)
- Feliks Kogan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Singh A, Cai K, Haris M, Hariharan H, Reddy R. On B1 inhomogeneity correction of in vivo human brain glutamate chemical exchange saturation transfer contrast at 7T. Magn Reson Med 2012; 69:818-24. [PMID: 22511396 DOI: 10.1002/mrm.24290] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/17/2012] [Accepted: 03/19/2012] [Indexed: 11/10/2022]
Abstract
The effects of radio frequency field (B(1)) inhomogeneity on measured in vivo human brain glutamate chemical exchange saturation transfer contrast maps are normally confounded with contributions from chemical exchange saturation transfer, direct saturation and magnetization transfer effects. Consequently, the chemical exchange saturation transfer effect variation with B(1) follows a complicated function and depends on the tissue types as well. In this work, we developed and tested a novel approach for B(1) inhomogeneity correction based on acquiring calibration data at a coarsely sampled B(1) values in conjunction with the measured B(1) maps. With this approach, different calibration curves are derived for gray matter and white matter instead of a simple linear scaling based on local B(1) values. Potential extensions of this approach to study chemical exchange saturation transfer contrast from other metabolites and tissue types are discussed.
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Affiliation(s)
- Anup Singh
- CMROI, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Singh A, Haris M, Cai K, Kassey VB, Kogan F, Reddy D, Hariharan H, Reddy R. Chemical exchange saturation transfer magnetic resonance imaging of human knee cartilage at 3 T and 7 T. Magn Reson Med 2011; 68:588-94. [PMID: 22213239 DOI: 10.1002/mrm.23250] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/12/2011] [Accepted: 09/16/2011] [Indexed: 11/10/2022]
Abstract
The sensitivity of chemical exchange saturation transfer (CEST) on glycosaminoglycans (GAGs) in human knee cartilage (gagCEST) in vivo was evaluated at 3 and 7 T field strengths. Calculated gagCEST values without accounting for B(0) inhomogeneity (~0.6 ppm) were >20%. After B(0) inhomogeneity correction, calculated gagCEST values were negligible at 3 T and ~6% at 7 T. These results suggest that accurate B(0) correction is a prerequisite for observing reliable gagCEST. Results obtained with varying saturation pulse durations and amplitudes as well as the consistency between numerical simulations and our experimental results indicate that the negligible gagCEST observed at 3 T is due to direct saturation effects and fast exchange rate. As GAG loss from cartilage is expected to result in a further reduction in gagCEST, gagCEST method is not expected to be clinically useful at 3 T. At high fields such as 7 T, this method holds promise as a viable clinical technique.
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Affiliation(s)
- Anup Singh
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, United States.
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Abstract
Myo-Inositol (MI) is one of the most abundant metabolites in the human brain located mainly in glial cells and functions as an osmolyte. The concentration of MI is altered in many brain disorders including Alzheimer's disease and brain tumors. Currently available magnetic resonance spectroscopy (MRS) methods for measuring MI are limited to low spatial resolution. Here, we demonstrate that the hydroxyl protons on MI exhibit chemical exchange with bulk water and saturation of these protons leads to reduction in bulk water signal through a mechanism known as chemical exchange saturation transfer (CEST). The hydroxyl proton exchange rate (k=600 s(-1)) is determined to be in the slow to intermediate exchange regime on the NMR time scale (chemical shift (∆ω)>k), suggesting that the CEST effect of MI (MICEST) can be imaged at high fields such as 7 T (∆ω=1.2×10(3)rad/s) and 9.4 T (∆ω=1.6×10(3) rad/s). Using optimized imaging parameters, concentration dependent broad CEST asymmetry between ~0.2 and 1.5 ppm with a peak at ~0.6 ppm from bulk water was observed. Further, it is demonstrated that MICEST detection is feasible in the human brain at ultra high fields (7 T) without exceeding the allowed limits on radiofrequency specific absorption rate. Results from healthy human volunteers (N=5) showed significantly higher (p=0.03) MICEST effect from white matter (5.2±0.5%) compared to gray matter (4.3±0.5%). The mean coefficient of variations for intra-subject MICEST contrast in WM and GM were 0.49 and 0.58 respectively. Potential overlap of CEST signals from other brain metabolites with the observed MICEST map is discussed. This noninvasive approach potentially opens the way to image MI in vivo and to monitor its alteration in many disease conditions.
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Affiliation(s)
- Mohammad Haris
- Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104-6100, USA
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