Purely Evidence Based Multiscale Cardiac Tracking Using Optic Flow

Heart disease can negatively influence cardiac pump function. To assess cardiac tissue function, a method based on classical optical flow theory applied in the spectral domain is presented. Assumption of pixel intensity conservation is replaced by assumption of spatial phase conservation. Simultaneous application to two independent observations of the same optical flow field removes the necessity of additional constraints (i.e. flow field smoothness, normal flow) to solve the optical flow constraint equation (OFCE). Using the 1 order Taylor expansion of the OFCE, our system yields not only pixel displacements, but also the 1 order differential structure of the displacements (i.e. strains), which otherwise should be calculated as a post-processing step. Operation at pixel level obviates the need for interpolation of tag lines or sparse flow field representation. Experiments show coherent flow fields of a human cardiac systole. Comparison with velocity encoded MRI shows a good resemblance.