2024-03-29T10:53:22Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/823222022-11-17T02:08:08Zhdl_2115_20053hdl_2115_145Simultaneous T-2* mapping of N-14- and N-15-labeled dicarboxy-PROXYLs using CW-EPR-based single-point imagingYokoyama, TakahitoTaguchi, AkihiroKubota, HarueStewart, Neil J.Matsumoto, ShingoKirilyuk, Igor A.Hirata, HiroshiEPRT-2* mappingNitroxyl radicalSingle-point imagingGradient-descent optimizationOxygenation540This article reports a method of simultaneous T-2* mapping of N-14- and N-15-labeled dicarboxy-PROXYLs using 750-MHz continuous-wave electron paramagnetic resonance (CW-EPR) imaging. To separate the spectra of N-14- and N-15-labeled dicarboxy-PROXYLs under magnetic field gradients, an optimization problem for spectral projections was formulated with the spatial total variation as a regularization term and solved using a local search based on the gradient descent algorithm. Using the single-point imaging (SPI) method with spectral projections of each radical, simultaneous T-2* mapping was performed for solution samples. Simultaneous T-2* mapping enabled visualization of the response of T-2* values to the level of dissolved oxygen in the solution. Simultaneous T-2* mapping applied to a mouse tumor model demonstrated the feasibility of the reported method for potential application to in vivo oxygenation imaging. (C) 2019 Elsevier Inc. All rights reserved.ElsevierJournal Articleapplication/pdfhttp://hdl.handle.net/2115/82322https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/82322/1/JMR-19-77Rev-1.pdf1090-7807AA11113784Journal of magnetic resonance3051221302019-08enginfo:doi/10.1016/j.jmr.2019.06.012©2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/author