One of the preferred embodiments includes: (a) creating a summed 3D nuclear medicine imaging data by summing a plurality of 3D nuclear medicine imaging data pixel by pixel (b) determining pixels corresponding to myocardial regions in the summed 3D nuclear medicine imaging data (c) defining a plurality of tracing directions based on the summed 3D nuclear medicine imaging data, and determining a reference myocardial center base point, a reference inner myocardial wall base point and a reference outer myocardial wall base point for each of the tracing directions (d) determining a phase-specific myocardial center base point for each of the tracing directions for each of the phases and (e) seeking a difference between the reference myocardial center base point and the phase-specific myocardial center base point, and determining a phase-specific inner myocardial wall base point and a phase-specific outer myocardial wall base point.
