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Single Acquisition Quantitative Single‐Point Electron Paramagnetic Resonance Imaging
Author(s) -
Jang Hyungseok,
Subramanian Sankaran,
Devasahayam Nallathamby,
Saito Keita,
Matsumoto Shingo,
Krishna Murali C.,
McMillan Alan B.
Publication year - 2013
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24886
Subject(s) - extrapolation , k space , nuclear magnetic resonance , electron paramagnetic resonance , encoding (memory) , physics , magnetic resonance imaging , phase (matter) , signal (programming language) , computational physics , chemistry , computer science , artificial intelligence , mathematics , fourier transform , mathematical analysis , medicine , quantum mechanics , radiology , programming language
Purpose Electron paramagnetic resonance imaging has emerged as a promising noninvasive technology to dynamically image tissue oxygenation. Owing to its extremely short spin–spin relaxation times, electron paramagnetic resonance imaging benefits from a single‐point imaging scheme where the entire free induction decay signal is captured using pure phase encoding. However, direct T 2 * /pO 2 quantification is inhibited owing to constant magnitude gradients which result in time‐decreasing field of view. Therefore, conventional acquisition techniques require repeated imaging experiments with differing gradient amplitudes (typically 3), which results in long acquisition time. Methods In this study, gridding was evaluated as a method to reconstruct images with equal field of view to enable direct T 2 * /pO 2 quantification within a single imaging experiment. Additionally, an enhanced reconstruction technique that shares high spatial k‐space regions throughout different phase‐encoding time delays was investigated (k‐space extrapolation). Results The combined application of gridding and k‐space extrapolation enables pixelwise quantification of T 2 * from a single acquisition with improved image quality across a wide range of phase‐encoding time delays. The calculated T 2 * /pO 2 does not vary across this time range. Conclusions By utilizing gridding and k‐space extrapolation, accurate T 2 * /pO 2 quantification can be achieved within a single data set to allow enhanced temporal resolution (by a factor of 3). Magn Reson Med, 70:1173–1181, 2013. © 2013 Wiley Periodicals, Inc.