disclosed is an ultrasound diagnosis device for creating an ultrasound image with a high contrast - to - tissue ratio . said device sends a transmission pulse to the subject , uses an ultrasound probe to receive echoes reflected from an ultrasound contrast agent injected into the subject , and forms an image . the transmission pulse is sent such that nonlinear interactions between the constituent frequency components of said transmission pulse , as a result of the acoustic nonlinearity of the subject , do not produce sum and difference components in the frequency sensitivity range of the ultrasonic probe as the transmission pulse propagates across the subject .