A time-domain electron paramagnetic resonance imaging method for producing a two-dimensional or three-dimensional quantitative oxygen image of a living tissue perfused with a paramagnetic spin probe, the method comprising: (a) applying to the tissue a spin echo pulse sequence comprising an excitation pulse and a refocusing pulse; (b) applying magnetic field gradients in discrete steps along the Cartesian axes, resulting in two-dimensional or three-dimensional phase-encoding of all the points in the EPR response of the tissue as a function of gradient steps and magnitude and of the delay time relative to the excitation pulse; (b) acquiring, for each phase-encoding gradient step, a first EPR signal sample at a single point in time Δt prior to the refocusing pulse and a second EPR signal sample at a single point in time Δt after the refocusing pulse, the first and second signal samples having identical net phase-encoding for each phase-encoding gradient step; (c) reconstructing a first image from the first EPR signals and a second image from the second EPR signals, the two images having the same field-of-view and the same spatial resolution; (d) determining at each corresponding pixel or voxel of the two images of the tissue a T 2 relaxation time from the slope of a linear fit as a function of time between the logarithms of the signal intensities of the first and second images; (e) determining for each pixel or voxel within the tissue an oxygen concentration from the T 2 relaxation time by interpolating a reference oxygen concentration from a predetermined table comprising a plurality of reference oxygen concentrations as a function of T 2 relaxation time; and (f) producing a quantitative two- or three-dimensional oxygen image of the tissue by mapping the oxygen concentration onto the location of each pixel or voxel within an image of the tissue. (a) applying to the tissue a spin echo pulse sequence comprising an excitation pulse and a refocusing pulse; (b) applying magnetic field gradients in discrete steps along the Cartesian axes, resulting in two-dimensional or three-dimensional phase-encoding of all the points in the EPR response of the tissue as a function of gradient steps and magnitude and of the delay time relative to the excitation pulse; (b) acquiring, for each phase-encoding gradient step, a first EPR signal sample at a single point in time Δt prior to the refocusing pulse and a second EPR signal sample at a single point in time Δt after the refocusing pulse, the first and second signal samples having identical net phase-encoding for each phase-encoding gradient step; (c) reconstructing a first image from the first EPR signals and a second image from the second EPR signals, the two images having the same field-of-view and the same spatial resolution; (d) determining at each corresponding pixel or voxel of the two images of the tissue a T 2 relaxation time from the slope of a linear fit as a function of time between the logarithms of the signal intensities of the first and second images; (e) determining for each pixel or voxel within the tissue an oxygen concentration from the T 2 relaxation time by interpolating a reference oxygen concentration from a predetermined table comprising a plurality of reference oxygen concentrations as a function of T 2 relaxation time; and (f) producing a quantitative two- or three-dimensional oxygen image of the tissue by mapping the oxygen concentration onto the location of each pixel or voxel within an image of the tissue.