Fig. 1.

A schematic of our image-based gating algorithm. As shown, the major steps are: (i) decimate images, (ii) determine cardiac period at each slice position, (iii) reassemble or wraparound data to produce one correctly ordered, unevenly spaced set of images from a cardiac cycle at each slice, (iv) interpolate linearly to create even temporal spacing, (v) determine relative shift from one slice to the next (vi) determine absolute time shift at each slice, and (vii) reorder image data to create volumes over the cardiac cycle.