title: Fast 3D spatial EPR imaging using spiral magnetic field gradient.
abstract: 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 4-7-fold accelerated acquisition of projections. This technique has great potential for in vivo studies of free radicals and their metabolism.
authors.affiliation: Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Room 114, 420 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Yuanmu
authors.initials: Y
authors.lastname: Deng
authors.forename: Sergy
authors.initials: S
authors.lastname: Petryakov
authors.forename: Guanglong
authors.initials: G
authors.lastname: He
authors.forename: Eric
authors.initials: E
authors.lastname: Kesselring
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
authors.forename: Jay L
authors.initials: JL
authors.lastname: Zweier
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008280:Magnetics; D008956:Models, Chemical; D008958:Models, Molecular; D012815:Signal Processing, Computer-Assisted