A 3D optical flow approach to addition of deformable PET volumes

A method for combining datasets from gated cardiac PET acquisitions is described. Optical flow techniques are used to accurately model non-rigid motion present during the cardiac cycle so that a one-to-one mapping is found between each voxel of two gated volumes. Using this mapping, images can be combined to produce a composite dataset with improved statistics and reduced motion-induced blur. Like recent past efforts in deformable motion, an image similarity measure is combined with elastic constraints to obtain a valid flow field. Additionally, because of the noisy characteristics of individual reconstructed volumes in a gated PET study, 4D and multiscale techniques were used in this paper to obtain more accurate motion estimates. Results using data from gated cardiac studies on canine and human subjects are presented.