Three-dimensional spectral-spatial EPR imaging of free radicals in the heart: a technique for imaging tissue metabolism and oxygenation.

Kuppusamy, Periannan; Chzhan, Michael; Vij, Kamal; Shteynbuk, Michael; Lefer, David J.; Giannella, E.; Zweíer, Jay L.

doi:10.1073/pnas.91.8.3388

Cited by 211 publications

(183 citation statements)

References 15 publications

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“…In addition, we observed that with subsequent i.v. administration of 0.3 ml of 100 mM Na 3 Fe(CN) 6 at a time 50 min post 3-CP infusion, an Ϸ50% return of total EPR signal was seen, confirming that much of the label was reversibly bioreduced within the body.…”

Section: Kinetics Of Nitroxide Radicals In the Whole Body And In Diffmentioning

confidence: 65%

“…Electron paramagnetic resonance imaging (EPRI) has been widely used to map the distribution and metabolism of paramagnetic species in isolated organs and other ex vivo and in vivo biological systems (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). However, in contrast to proton NMR-based MRI, EPRI only detects the distribution and kinetics of free radicals, and consequently these images may not resemble the anatomic structure of the imaged object.…”

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confidence: 99%

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EPR/NMR co‐imaging for anatomic registration of free‐radical images

Deng

et al. 2002

Magnetic Resonance in Med

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While electron paramagnetic resonance imaging (EPRI) enables spatial mapping of free radicals in the whole body of small animals, it solely visualizes the free-radical distribution and does not typically provide anatomic visualization of the body. However, anatomic registration is often required for meaningful interpretation of the EPRI-derived free-radical images. An approach is reported for whole-body, EPRI-based, free-radical imaging along with proton MRI in mice. EPRI instrumentation with a 750-MHz narrow band microwave bridge and transverse oriented electric field reentrant resonator, with automatic coupling control and automatic tuning control capability, was used to map the spatial distribution of nitroxide free radicals in phantoms and in living mice, while low-field proton MRI at 16 MHz was used to define the anatomic structure to register the EPR images. Small capillary tubes containing an aqueous radical label were used as markers to enable image superimposition. With this coregistration technique, the EPRI free-radical images were precisely registered, enabling assignment of the location of the observed free-radical distribution within the organs of the mice. Key words: in vivo EPR; in vivo NMR; proton MRI; co-imaging; automatic tuning; automatic couplingElectron paramagnetic resonance imaging (EPRI) has been widely used to map the distribution and metabolism of paramagnetic species in isolated organs and other ex vivo and in vivo biological systems (1-10). However, in contrast to proton NMR-based MRI, EPRI only detects the distribution and kinetics of free radicals, and consequently these images may not resemble the anatomic structure of the imaged object. Therefore, development of independent approaches for anatomic registration of EPR image data is of critical importance to facilitate accurate assignment of the distribution of free radicals within the body.Proton MRI has been well established over the last two decades as a precise method for the noninvasive delineation of internal anatomic structure, and has been widely applied in a wide range of research and clinical applications. As an MR technique, it is particularly powerful for anatomic mapping due to the high concentration and narrow linewidth of water protons in biological systems (11)(12)(13)(14)(15). By employing NMR images to define the anatomic structure with appropriate markers visualized by both EPRI and proton MRI, appropriate superimposition/registration can in principle be performed. This EPR/NMR coimaging (ENCI), while a seemingly simple concept, presents a number of unique technical challenges. These problems are primarily based on the need for high-resolution EPRI mapping of the registration markers and biological samples, appropriate NMR/EPR-detectable markers, and mechanical and computational approaches to appropriately fix the sample orientations and superimpose the images obtained. Largely because of these challenges, this type of co-imaging technique with 2D or 3D EPR image registration has not been previously achieved.App...

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Section: Kinetics Of Nitroxide Radicals In the Whole Body And In Diffmentioning

confidence: 65%

mentioning

confidence: 99%

EPR/NMR co‐imaging for anatomic registration of free‐radical images

Deng

et al. 2002

Magnetic Resonance in Med

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“…19 Isolated rat hearts were perfused at 37 C in a constant pressure mode with Krebs bicarbonate-buffered perfusate solution. Hearts were infused with 1 mM TEMPO (2,2,5,5-tetramethylpiperidine-Noxyl) for 10 min to reach steady state and EPR acquisitions of 64 projections were performed every 12 min.…”

Section: Imaging Of Myocardial Metabolism Of Nitroxyl Radicals and Oxmentioning

confidence: 99%

“…[9][10][11][12][13][14][15][16][17][18] Over the last decade we have focused on developing instrumentation optimized for measurements of free radicals in isolated beating hearts, and in recent several years we have extended our efforts to develop hardware and software to enable spatial and spectral-spatial imaging of free radicals in the heart. 9,[19][20][21][22][23][24][25] This review provides a summary of the development and application of the imaging techniques with examples including imaging of stable free radical labels, oxygen concentrations and nitric oxide generation in the normal or ischemic heart.…”

Section: Introductionmentioning

confidence: 99%

Cardiac applications of EPR imaging

Kuppusamy

Zweíer

2004

NMR in Biomedicine

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This review summarizes the development and application of a variety of EPR imaging modalities including spatial, spectral-spatial (spectroscopic), gated-imaging and oxygen mapping to cardiovascular studies. It has been hypothesized that free radical metabolism, oxygenation and nitric oxide generation in biological organs such as the heart may vary over the spatially defined tissue structure. We have developed instrumentation optimized for 3D spatial and 3D or 4D spectral-spatial imaging of free radicals at 1.2 GHz. Using this instrumentation high quality 3D spectral-spatial imaging of nitroxyl (nitroxide) metabolism was performed, as well as spatially localized measurements of oxygen concentrations, based on the oxygen-dependent line-broadening of the EPR spectrum. Both exogenously infused probes and endogenous radicals were used to obtain the images. It is demonstrated that the EPR imaging is a powerful tool which can provide unique information regarding the spatial localization of free radicals, oxygen and nitric oxide in biological organs and tissues.

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“…However, due to the nature of field sweep, the imaging time in CW EPRI is relatively long (11). For example, it typically takes several minutes for a conventional EPR imaging system to acquire a 2D image and tens of minutes for a 3D image (12). The long imaging time prevents the use of this technique for many biological applications where the free radicals have a short lifetime or a rapid metabolic clearance (13).…”

Section: Introductionmentioning

confidence: 99%

Fast 3D spatial EPR imaging using spiral magnetic field gradient

Deng

Petryakov

et al. 2007

Journal of Magnetic Resonance

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Electron paramagnetic resonance imaging (EPRI) provides direct detection and mapping of free radicals. The continuous wave (CW) EPRI technique, in particular, has been widely used in a variety of applications in the fields of biology and medicine due to its high sensitivity and applicability to a wide range of free radicals and paramagnetic species. However, the technique requires long image acquisition periods, and this limits its use for many in vivo applications where relatively rapid changes occur in the magnitude and distribution of spins. Therefore, there has been a great need to develop fast EPRI techniques. We report the development of a fast 3D CW EPRI technique using spiral magnetic field gradient. By spiraling the magnetic field gradient and stepping the main magnetic field, this approach acquires a 3D image in one sweep of the main magnetic field, enabling significant reduction of the imaging time. A direct one-stage 3D image reconstruction algorithm, modified for reconstruction of the EPR images from the projections acquired with the spiral magnetic field gradient, was used. We demonstrated using a home-built L-band EPR system that the spiral magnetic field gradient technique enabled a 4 to 7-fold accelerated acquisition of projections. This technique has great potential for in vivo studies of free radicals and their metabolism.

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Three-dimensional spectral-spatial EPR imaging of free radicals in the heart: a technique for imaging tissue metabolism and oxygenation.

Cited by 211 publications

References 15 publications

EPR/NMR co‐imaging for anatomic registration of free‐radical images

EPR/NMR co‐imaging for anatomic registration of free‐radical images

Cardiac applications of EPR imaging

Fast 3D spatial EPR imaging using spiral magnetic field gradient

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