An apparatus can be used to generate acoustic imaging pulse sequences and receive corresponding echoes elicited by the acoustic imaging pulse sequences. An acoustic radiation force (ARF) pulse sequence can be generated to agitate a contrast medium in a tissue region between the acoustic imaging pulse sequences. A decorrelation between images corresponding to the received echoes can be determined. A weighting map can be applied to an image to weight a region of the image corresponding to a spatial location of the contrast medium using the determined decorrelation. In an example, the receiving of corresponding echoes elicited by the acoustic imaging pulse sequences can include receiving acoustic energy having a range of frequencies offset from a fundamental frequency associated with the acoustic imaging pulse sequences. An acoustic imaging pulse sequence can include a pulse having an inverted amplitude envelope with respect to another pulse included in the sequence.