Enhanced resolution for EPR imaging by two-step deblurring

Abstract

The broad spectrum of spin probes used for electron paramagnetic resonance imaging (EPRI) result in poor spatial resolution of the reconstructed images. Conventional deconvolution procedures can enhance the resolution to some extent but obtaining high resolution EPR images is still a challenge. In this work, we have implemented and analyzed the performance of a postacquisition deblurring technique to enhance the spatial resolution of the EPR images. The technique consists of two steps; noniterative deconvolution followed by iterative deconvolution of the acquired projections which are then projected back using filtered backprojection (FBP) to reconstruct a high resolution image. Further, we have proposed an analogous technique for the iterative reconstruction algorithms such as multiplicative simultaneous iterative reconstruction technique (MSIRT) which can be a method of choice for many applications. The performance of the suggested deblurring approach is evaluated using computer simulations and EPRI experiments. Results suggest that the proposed procedure is superior to the standard FBP and standard iterative reconstruction algorithms in terms of meansquare-error (MSE), spatial resolution, and visual judgment. Although the procedure is described for 2D imaging, it can be readily extended to 3D imaging.

Development and testing of a CW-EPR apparatus for imaging of short-lifetime nitroxyl radicals in mouse head

“…This is because the low-pass window function sacrificed the high-frequency components of the spatial distribution of the spin probes. In this case, spatial resolution could be improved by superresolution EPR imaging techniques, i.e., iterative deconvolution techniques [32,33]. However, the detailed discussion of methods to deblur images are beyond the scope of this article.…”

How In Vivo EPR Measures and Images Oxygen

“…Different reconstruction algorithms have been developed for radially sampled data. Most of them fall into one of two categories: filtered back projection (FBP) [8,9] or iterative reconstruction [10]. All reconstruction procedures on sparsely sampled data give inexact results: they represent a compromise between accuracy and the computation time required.…”

Implementation of GPU-accelerated back projection for EPR imaging

“…Pulse EPRI is advantageous in certain situations compared to CW EPRI because of its faster imaging speed. For tomographic 3D pulse EPRI, the classical image reconstruction algorithm is the 3D FBP algorithm [9][10], which derives from 3D inverse radon transform.…”