1. A method comprising: acquiring a first plurality of images of a first portion of a body undergoing substantially periodic motion; acquiring a second plurality of images of a second portion of the body, the second portion comprising a portion of the first portion; determining a correlation between at least one of the first plurality of images and at least one of the second plurality of images; and generating a combined image of the first portion and the second portion based on the at least one of the first plurality of images and the at least one of the second plurality of images, the combined image corresponding to a first phase of the periodic motion.