Ultrasonic Diagnostic Contrast Imaging at Moderate Mi Levels

摘要

A method and device for imaging contrast agents which oscillate nonlinearly in a nondestructive mode at an MI in excess of 0.1 is described. Three transmit pulses are transmitted in each beam direction which are differently modulated. In an illustrated embodiment the transmit pulses are symmetrically differently phase modulated at 0°, 120° and 240°. The echoes received in response to each transmit pulse are stored and combined by a pulse inversion processor. Pulse inversion processing results in separation of the third harmonic to the relative exclusion of the first and second harmonic signal components. Third harmonic images of the contrast image are formed which exhibit a relatively low tissue background.