Figure 1

(a) Cartesian and radial k-space sampling patterns with the same number of readouts and readout resolution; (b) corresponding point-spread function (absolute value of the PSF) in image domain for Cartesian acquisition; (c) PSF for radial acquisition. Insufficient k-space coverage along Ky (phase-encode direction) results in significant ringing along y, as shown in (b). Panels (d)-(f) show reconstructions of an MR gelatin-Gadolinium phantom with realistic signal intensity ratios, demonstrating robustness of projection imaging to Gibbs ringing: (d) fully sampled (ground truth) image with 1x1 mm resolution (384x384 matrix); (e) Cartesian imaging with 108 phase-encodes (arrows point to DRA); (f) radial imaging with 108 projections (no DRAs, mild streaking).