Regularized optimization (RO) reconstruction for oximetric EPR imaging

Tseitlin, Mark; Czechowski, Tomasz; Eaton, Gareth R.

doi:10.1016/j.jmr.2008.07.002

Cited by 18 publications

(12 citation statements)

References 31 publications

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“…Rapid-scan signals can be deconvolved to give the slowscan absorption spectrum (20,21). Rapid-scan EPR was initially developed at 250 MHz for applications to in vivo imaging (22)(23)(24). A historical perspective of the method is provided in Stoner et al (22).…”

Section: Superoxide (Omentioning

confidence: 99%

Use of Rapid-Scan EPR to Improve Detection Sensitivity for Spin-Trapped Radicals

Mitchell

Rosen

Tseitlin

et al. 2013

Biophysical Journal

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The short lifetime of superoxide and the low rates of formation expected in vivo make detection by standard continuous wave (CW) electron paramagnetic resonance (EPR) challenging. The new rapid-scan EPR method offers improved sensitivity for these types of samples. In rapid-scan EPR, the magnetic field is scanned through resonance in a time that is short relative to electron spin relaxation times, and data are processed to obtain the absorption spectrum. To validate the application of rapid-scan EPR to spin trapping, superoxide was generated by the reaction of xanthine oxidase and hypoxanthine with rates of 0.1-6.0 μM/min and trapped with 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO). Spin trapping with BMPO to form the BMPO-OOH adduct converts the very short-lived superoxide radical into a more stable spin adduct. There is good agreement between the hyperfine splitting parameters obtained for BMPO-OOH by CW and rapid-scan EPR. For the same signal acquisition time, the signal/noise ratio is >40 times higher for rapid-scan than for CW EPR. Rapid-scan EPR can detect superoxide produced by Enterococcus faecalis at rates that are too low for detection by CW EPR.

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Section: Superoxide (Omentioning

confidence: 99%

Use of Rapid-Scan EPR to Improve Detection Sensitivity for Spin-Trapped Radicals

Mitchell

Rosen

Tseitlin

et al. 2013

Biophysical Journal

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“…The measured full widths at half height of the EPR signals in the tubes were 148, 49, and 169 mG, respectively. The sample preparation details are described elsewhere [13]. …”

Section: Methodsmentioning

confidence: 99%

Combining absorption and dispersion signals to improve signal-to-noise for rapid-scan EPR imaging

Tseitlin

Quine

Rinard

et al. 2010

Journal of Magnetic Resonance

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Direct detection of the rapid scan EPR signal with quadrature detection and without automatic frequency control provides both the absorption and dispersion components of the signal. The use of a cross-loop resonator results in similar signal-to-noise in the two channels. The dispersion signal can be converted to an equivalent absorption signal by means of Kramers-Kronig relations. The converted signal is added to the directly-measured absorption signal. Since the noise in the two channels is not correlated, this procedure increases the signal-to-noise ratio of the resultant absorption signal by up to a factor of √2. The utility of this method was demonstrated for 2D spectral-spatial imaging of a phantom containing 3 tubes of LiPc with different oxygen concentrations and therefore different linewidths.

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“…Similarly to [31], [39] and [4], we assume that the data is corrupted with an additive independant gaussian white noise denoted n, thus yielding the direct model of spatial EPRI acquisition…”

Section: Direct Modelmentioning

confidence: 99%

Electron paramagnetic resonance image reconstruction with total variation and curvelets regularization

2017

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Spatial electron paramagnetic resonance imaging (EPRI) is a recent method to localize and characterize free radicals in vivo or in vitro, leading to applications in material and biomedical sciences. To improve the quality of the reconstruction obtained by EPRI, a variational method is proposed to inverse the image formation model. It is based on a leastsquare data-fidelity term and the total variation and Besov seminorm for the regularization term. To fully comprehend the Besov seminorm, an implementation using the curvelet transform and the L 1 norm enforcing the sparsity is proposed. It allows our model to reconstruct both image where acquisition information are missing and image with details in textured areas, thus opening possibilities to reduce acquisition times. To implement the minimization problem using the algorithm developed by Chambolle and Pock, a thorough analysis of the direct model is undertaken and the latter is inverted while avoiding the use of filtered backprojection (FBP) and of non-uniform Fourier transform. Numerical experiments are carried out on simulated data, where the proposed model outperforms both visually and quantitatively the classical model using deconvolution and FBP. Improved reconstructions on real data, acquired on an irradiated distal phalanx, were successfully obtained.

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Regularized optimization (RO) reconstruction for oximetric EPR imaging

Cited by 18 publications

References 31 publications

Use of Rapid-Scan EPR to Improve Detection Sensitivity for Spin-Trapped Radicals

Use of Rapid-Scan EPR to Improve Detection Sensitivity for Spin-Trapped Radicals

Combining absorption and dispersion signals to improve signal-to-noise for rapid-scan EPR imaging

Electron paramagnetic resonance image reconstruction with total variation and curvelets regularization

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