EFFECTS OF POLAR SAMPLING IN K-SPACE

Magnetic resonance imaging allows numerous k-space sampling schemes su ch as cartesian, polar, spherical, and other non-rectilinear trajector ies. Non-rectilinear MR acquisitions permit fast scan times and can su ppress motion artifacts. Still, these sampling schemes may adversely a ffect the image characteristics due to aliasing. Here, the Fourier ali asing effects of uniform polar sampling, i.e., equally spaced radial a nd azimuthal samples, are explained from the principal point spread fu nction (PSF). The principal PSF is determined by assuming equally spac ed concentric ring samples in k-space. The radial effects such as repl ication, smearing, truncation artifacts, and sampling requirements, ar e characterized based on the PSF.