1. A method for combining at least two frames of ultrasound data with an ultrasound system, the method comprising the acts of: (a) selecting ultrasound data corresponding to at least one structure feature of a target in a first of the at least two frames of ultrasound data; (b) estimating motion between the first and a second of the at least two frames of ultrasound data as a function of the at least one structure feature; and (c) combining the first and second frames of ultrasound data as a function of the estimated motion.