Motion-compensated reconstruction of dynamic cardiac images

In this paper we present a new approach for estimating the dynamics (uptake and washout) of a radio-pharmaceutical in the myocardium. To account for the heart motion, the cardiac cycle is divided into a number of intervals as in gated SPECT. Within each gated frame, the time evolution at a pixel is modeled by a spline function. The spline control points are then reconstructed using a Bayesian framework, in which a smoothing prior is defined on all the gated frames based on the motion of the heart. A globally convergent incremental gradient algorithm is used for the optimization step. The proposed algorithm is evaluated using a dynamic version of the 4D gated mathematical cardiac torso (gMCAT) phantom to simulate a gated SPECT perfusion acquisition with Tc-99m Teboroxime. Our results demonstrate that the use of motion compensation can improve significantly the accuracy of the reconstruction.