1. A method of forming an ultrasound image, the method comprising: transmitting an unfocused first circular wave front ultrasound signal into a region of interest from a first transmit aperture and receiving echoes of the first circular wave front ultrasound signal at a first receive aperture to form a first image layer; transmitting an unfocused second circular wave front ultrasound signal into a region of interest from a second transmit aperture and receiving echoes of the second circular wave front ultrasound signal at the first receive aperture to form a second image layer; applying a weighting factor to at least one pixel of the first image layer to obtain a modified first image layer; and combining the modified first image layer with the second image layer to form a combined image.