Spatial resolution in SPEN-imaging is determined by the spatial phase dispersion imprinted on the acquired signal by a frequency-swept excitation or refocusing pulse. The resulting signal attenuation increases with larger distance from the vertex of the quadratic phase profile.
Bloch simulations and experiments were performed to validate theoretical derivations.
The apparent PSF quantifies the fractional contribution of magnetization to a voxel's signal as a function of distance to the voxel. In contrast, the conventional PSF represents the signal intensity at various locations.
The definition of the conventional PSF fails for SPEN-imaging since only the phase of isochromats, but not the amplitude of the signal varies. The concept of the apparent PSF is shown to be generalizable to conventional Fourier-imaging techniques.