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Qiao Z, Redler G, Epel B, Qian Y, Halpern H. Implementation of GPU-accelerated back projection for EPR imaging. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2015; 23:423-33. [PMID: 26410654 PMCID: PMC4825055 DOI: 10.3233/xst-150498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electron paramagnetic resonance (EPR) Imaging (EPRI) is a robust method for measuring in vivo oxygen concentration (pO2). For 3D pulse EPRI, a commonly used reconstruction algorithm is the filtered backprojection (FBP) algorithm, in which the backprojection process is computationally intensive and may be time consuming when implemented on a CPU. A multistage implementation of the backprojection can be used for acceleration, however it is not flexible (requires equal linear angle projection distribution) and may still be time consuming. In this work, single-stage backprojection is implemented on a GPU (Graphics Processing Units) having 1152 cores to accelerate the process. The GPU implementation results in acceleration by over a factor of 200 overall and by over a factor of 3500 if only the computing time is considered. Some important experiences regarding the implementation of GPU-accelerated backprojection for EPRI are summarized. The resulting accelerated image reconstruction is useful for real-time image reconstruction monitoring and other time sensitive applications.
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Affiliation(s)
- Zhiwei Qiao
- School of Computer and Information Technology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Gage Redler
- Department of Medical Physics, Rush Hospital, Chicago, IL , USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL 60637, USA
| | - Yuhua Qian
- School of Computer and Information Technology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Howard Halpern
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL 60637, USA
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2
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Qiao Z, Redler G, Epel B, Halpern HJ. Comparison of parabolic filtration methods for 3D filtered back projection in pulsed EPR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 248:42-53. [PMID: 25314081 PMCID: PMC4324566 DOI: 10.1016/j.jmr.2014.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 05/16/2023]
Abstract
Pulse electron paramagnetic resonance imaging (Pulse EPRI) is a robust method for noninvasively measuring local oxygen concentrations in vivo. For 3D tomographic EPRI, the most commonly used reconstruction algorithm is filtered back projection (FBP), in which the parabolic filtration process strongly influences image quality. In this work, we designed and compared 7 parabolic filtration methods to reconstruct both simulated and real phantoms. To evaluate these methods, we designed 3 error criteria and 1 spatial resolution criterion. It was determined that the 2 point derivative filtration method and the two-ramp-filter method have unavoidable negative effects resulting in diminished spatial resolution and increased artifacts respectively. For the noiseless phantom the rectangular-window parabolic filtration method and sinc-window parabolic filtration method were found to be optimal, providing high spatial resolution and small errors. In the presence of noise, the 3 point derivative method and Hamming-window parabolic filtration method resulted in the best compromise between low image noise and high spatial resolution. The 3 point derivative method is faster than Hamming-window parabolic filtration method, so we conclude that the 3 point derivative method is optimal for 3D FBP.
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Affiliation(s)
- Zhiwei Qiao
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA; School of Computer and Control Engineering, North University of China, Taiyuan, Shanxi 030051, China
| | - Gage Redler
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA
| | - Howard J Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.
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Swartz HM, Williams BB, Zaki BI, Hartford AC, Jarvis LA, Chen EY, Comi RJ, Ernstoff MS, Hou H, Khan N, Swarts SG, Flood AB, Kuppusamy P. Clinical EPR: unique opportunities and some challenges. Acad Radiol 2014; 21:197-206. [PMID: 24439333 DOI: 10.1016/j.acra.2013.10.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/03/2013] [Accepted: 10/14/2013] [Indexed: 11/29/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy has been well established as a viable technique for measurement of free radicals and oxygen in biological systems, from in vitro cellular systems to in vivo small animal models of disease. However, the use of EPR in human subjects in the clinical setting, although attractive for a variety of important applications such as oxygen measurement, is challenged with several factors including the need for instrumentation customized for human subjects, probe, and regulatory constraints. This article describes the rationale and development of the first clinical EPR systems for two important clinical applications, namely, measurement of tissue oxygen (oximetry) and radiation dose (dosimetry) in humans. The clinical spectrometers operate at 1.2 GHz frequency and use surface-loop resonators capable of providing topical measurements up to 1 cm depth in tissues. Tissue pO2 measurements can be carried out noninvasively and repeatedly after placement of an oxygen-sensitive paramagnetic material (currently India ink) at the site of interest. Our EPR dosimetry system is capable of measuring radiation-induced free radicals in the tooth of irradiated human subjects to determine the exposure dose. These developments offer potential opportunities for clinical dosimetry and oximetry, which include guiding therapy for individual patients with tumors or vascular disease by monitoring of tissue oxygenation. Further work is in progress to translate this unique technology to routine clinical practice.
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Affiliation(s)
- Harold M Swartz
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766.
| | - Benjamin B Williams
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766
| | - Bassem I Zaki
- Department of Medicine, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Alan C Hartford
- Department of Medicine, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Eunice Y Chen
- Department of Surgery, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Richard J Comi
- Department of Medicine, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Marc S Ernstoff
- Department of Medicine, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, NH
| | - Huagang Hou
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766
| | - Nadeem Khan
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766
| | - Steven G Swarts
- Dept. of Radiation Oncology, University of Florida, Gainesville, FL
| | - Ann B Flood
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766
| | - Periannan Kuppusamy
- Department of Radiology, Geisel School of Medicine at Dartmouth, Dartmouth College, 48 Lafayette Street, Lebanon, NH 03766
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Johnson DH, Ahmad R, He G, Samouilov A, Zweier JL. Compressed sensing of spatial electron paramagnetic resonance imaging. Magn Reson Med 2013; 72:893-901. [PMID: 24123102 DOI: 10.1002/mrm.24966] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/26/2013] [Accepted: 09/03/2013] [Indexed: 12/20/2022]
Abstract
PURPOSE To improve image quality and reduce data requirements for spatial electron paramagnetic resonance imaging (EPRI) by developing a novel reconstruction approach using compressed sensing (CS). METHODS EPRI is posed as an optimization problem, which is solved using regularized least-squares with sparsity promoting penalty terms, consisting of the l1 norms of the image itself and the total variation of the image. Pseudo-random sampling was employed to facilitate recovery of the sparse signal. The reconstruction was compared with the traditional filtered back-projection reconstruction for simulations, phantoms, isolated rat hearts, and mouse gastrointestinal (GI) tracts labeled with paramagnetic probes. RESULTS A combination of pseudo-random sampling and CS was able to generate high-fidelity EPR images at high acceleration rates. For three-dimensional (3D) phantom imaging, CS-based EPRI showed little visual degradation at nine-fold acceleration. In rat heart datasets, CS-based EPRI produced high quality images with eight-fold acceleration. A high resolution mouse GI tract reconstruction demonstrated a visual improvement in spatial resolution and a doubling in signal-to-noise ratio (SNR). CONCLUSION A novel 3D EPRI reconstruction using compressed sensing was developed and offers superior SNR and reduced artifacts from highly undersampled data.
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Affiliation(s)
- David H Johnson
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Epel, B, Halpern H. Electron paramagnetic resonance oxygen imaging in vivo. ELECTRON PARAMAGNETIC RESONANCE 2012. [DOI: 10.1039/9781849734837-00180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This review covers the last 15 years of the development of EPR in vivo oxygen imaging. During this time, a number of major technological and methodological advances have taken place. Narrow line width, long relaxation time, and non-toxic triaryl methyl radicals were introduced in the late 1990s. These not only improved continuous wave (CW) imaging, but also enabled the application of pulse EPR imaging to animals. Recent developments in pulse technology have brought an order of magnitude increase in image acquisition speed, enhancement of sensitivity, and considerable improvement in the precision and accuracy of oxygen measurements. Consequently, pulse methods take up a significant part of this review.
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Affiliation(s)
- Boris Epel,
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
| | - Howard Halpern
- Center for EPR Imaging in vivo Physiology the University of Chicago, Department of Radiation and Cellular Oncology (MC 1105), Chicago Illinois 60637
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Palmer J, Potter L, Johnson D, Zweier J, Ahmad R. Dual-scan acquisition for accelerated continuous-wave EPR oximetry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 222:53-58. [PMID: 22820009 PMCID: PMC3423522 DOI: 10.1016/j.jmr.2012.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/11/2012] [Accepted: 05/26/2012] [Indexed: 06/01/2023]
Abstract
Statistical analysis reveals that, given a fixed acquisition time, linewidth (and thus pO(2)) can be more precisely determined from multiple scans with different modulation amplitudes and sweep widths than from a single-scan. For a Lorentzian lineshape and an unknown but spatially uniform modulation amplitude, the analysis suggests the use of two scans, each occupying half of the total acquisition time. We term this mode of scanning as dual-scan acquisition. For unknown linewidths in a range [Γ(min), Γ(max)], practical guidelines are provided for selecting the modulation amplitude and sweep width for each dual-scan component. Following these guidelines can allow for a 3-4 times reduction in spectroscopic acquisition time versus an optimized single-scan, without requiring hardware modifications. Findings are experimentally verified using L-band spectroscopy with an oxygen-sensitive particulate probe.
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Affiliation(s)
- J. Palmer
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - L.C. Potter
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - D.H. Johnson
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - J.L. Zweier
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - R. Ahmad
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
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Bézière N, Decroos C, Mkhitaryan K, Kish E, Richard F, Bigot-Marchand S, Durand S, Cloppet F, Chauvet C, Corvol MT, Rannou F, Xu-Li Y, Mansuy D, Peyrot F, Frapart YM. First Combined in Vivo X-Ray Tomography and High-Resolution Molecular Electron Paramagnetic Resonance (EPR) Imaging of the Mouse Knee Joint Taking into Account the Disappearance Kinetics of the EPR Probe. Mol Imaging 2012. [DOI: 10.2310/7290.2011.00042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Nicolas Bézière
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Christophe Decroos
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Karen Mkhitaryan
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Elizabeth Kish
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Frédéric Richard
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Stéphanie Bigot-Marchand
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Sylvain Durand
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Florence Cloppet
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Caroline Chauvet
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Marie-Thérèse Corvol
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - François Rannou
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Yun Xu-Li
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Daniel Mansuy
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Fabienne Peyrot
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
| | - Yves-Michel Frapart
- From CNRS UMR 8601, Université Paris Descartes, LCPBT; CNRS UMR 8145, Université Paris Descartes, MAP5, Université Paris Descartes, LIPADE, EA2517, Université Paris Descartes, INSERM UMR-S747, Department of Physical Medicine and Rehabilitation, Cochin Hospital (AP-HP), Université Paris Descartes; and Université Paris Sorbonne-IUFM de Paris, Paris, France
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8
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Ahmad R, Som S, Johnson DH, Zweier JL, Kuppusamy P, Potter LC. Multisite EPR oximetry from multiple quadrature harmonics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 214:135-143. [PMID: 22154283 PMCID: PMC3257390 DOI: 10.1016/j.jmr.2011.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/24/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Multisite continuous wave (CW) electron paramagnetic resonance (EPR) oximetry using multiple quadrature field modulation harmonics is presented. First, a recently developed digital receiver is used to extract multiple harmonics of field modulated projection data. Second, a forward model is presented that relates the projection data to unknown parameters, including linewidth at each site. Third, a maximum likelihood estimator of unknown parameters is reported using an iterative algorithm capable of jointly processing multiple quadrature harmonics. The data modeling and processing are applicable for parametric lineshapes under nonsaturating conditions. Joint processing of multiple harmonics leads to 2-3-fold acceleration of EPR data acquisition. For demonstration in two spatial dimensions, both simulations and phantom studies on an L-band system are reported.
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Affiliation(s)
- R Ahmad
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
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Ahmad R, Som S, Kesselring E, Kuppusamy P, Zweier JL, Potter LC. Digital detection and processing of multiple quadrature harmonics for EPR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:322-31. [PMID: 20971667 PMCID: PMC2993834 DOI: 10.1016/j.jmr.2010.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 09/24/2010] [Accepted: 09/24/2010] [Indexed: 05/12/2023]
Abstract
A quadrature digital receiver and associated signal estimation procedure are reported for L-band electron paramagnetic resonance (EPR) spectroscopy. The approach provides simultaneous acquisition and joint processing of multiple harmonics in both in-phase and out-of-phase channels. The digital receiver, based on a high-speed dual-channel analog-to-digital converter, allows direct digital down-conversion with heterodyne processing using digital capture of the microwave reference signal. Thus, the receiver avoids noise and nonlinearity associated with analog mixers. Also, the architecture allows for low-Q anti-alias filtering and does not require the sampling frequency to be time-locked to the microwave reference. A noise model applicable for arbitrary contributions of oscillator phase noise is presented, and a corresponding maximum-likelihood estimator of unknown parameters is also reported. The signal processing is applicable for Lorentzian lineshape under nonsaturating conditions. The estimation is carried out using a convergent iterative algorithm capable of jointly processing the in-phase and out-of-phase data in the presence of phase noise and unknown microwave phase. Cramér-Rao bound analysis and simulation results demonstrate a significant reduction in linewidth estimation error using quadrature detection, for both low and high values of phase noise. EPR spectroscopic data are also reported for illustration.
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Affiliation(s)
- R Ahmad
- Center of Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
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10
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Ahmad R, Caia G, Potter L, Petryakov S, Kuppusamy P, Zweier J. In vivo multisite oximetry using EPR-NMR coimaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:69-77. [PMID: 20850361 PMCID: PMC2956866 DOI: 10.1016/j.jmr.2010.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 05/19/2010] [Accepted: 08/17/2010] [Indexed: 05/29/2023]
Abstract
Coimaging employing electron paramagnetic resonance (EPR) imaging and MRI is used for rapid in vivo oximetry conducted simultaneously across multiple organs of a mouse. A recently developed hybrid EPR-NMR coimaging instrument is used for both EPR and NMR measurements. Oxygen sensitive particulate EPR probe is implanted in small localized pockets, called sites, across multiple regions of a live mouse. Three dimensional MRI is used to generate anatomic visualization, providing precise locations of implant sites. The pO₂ values, one for every site, are then estimated from EPR measurements. To account for radio frequency (RF) phase inhomogeneities inside a large resonator carrying a lossy sample, a generalization of an existing EPR data model is proposed. Utilization of known spectral lineshape, sparse distribution, and known site locations reduce the EPR data collection by more than an order of magnitude over a conventional spectral-spatial imaging, enhancing the feasibility of in vivo EPR oximetry for clinically relevant models.
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Affiliation(s)
- R. Ahmad
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - G. Caia
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - L.C. Potter
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - S. Petryakov
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - P. Kuppusamy
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - J.L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
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11
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Ahmad R, Kuppusamy P. Theory, instrumentation, and applications of electron paramagnetic resonance oximetry. Chem Rev 2010; 110:3212-36. [PMID: 20218670 PMCID: PMC2868962 DOI: 10.1021/cr900396q] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Rizwan Ahmad
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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12
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Li H, Hou H, Sucheta A, Williams BB, Lariviere JP, Khan MN, Lesniewski PN, Gallez B, Swartz HM. Implantable resonators--a technique for repeated measurement of oxygen at multiple deep sites with in vivo EPR. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 662:265-72. [PMID: 20204802 PMCID: PMC3806631 DOI: 10.1007/978-1-4419-1241-1_38] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
EPR oximetry using implantable resonators allows measurements at much deeper sites than are possible with surface resonators (> 80 vs. 10 mm) and achieves greater sensitivity at any depth. We report here the development of an improved technique that enables us to obtain the information from multiple sites and at a variety of depths. The measurements from the various sites are resolved using a simple magnetic field gradient. In the rat brain multi-probe implanted resonators measured pO(2) at several sites simultaneously for over 6 months under normoxic, hypoxic, and hyperoxic conditions. This technique also facilitates measurements in moving parts of the animal such as the heart, because the orientation of the paramagnetic material relative to the sensing loop is not altered by the motion. The measured response is fast, enabling measurements in real time of physiological and pathological changes such as experimental cardiac ischemia in the mouse heart. The technique also is quite useful for following changes in tumor pO(2), including applications with simultaneous measurements in tumors and adjacent normal tissues.
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Affiliation(s)
- Hongbin Li
- EPR Center for Viable Systems, Department of Radiology, Dartmouth Medical School, 703, Vail, Hanover, NH 03755, USA
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