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 to obtain more accurate motion estimates. Results using data from gated cardiac studies on canine and human subjects are presented