A NOVEL ULTRASONIC TECHNIQUE FOR DIFFERENTIATING CYSTS FROM SOLID LESIONS - PRELIMINARY-RESULTS IN THE BREAST

The feasibility of a new ultrasonic technique to distinguish cysts fro m solid lesions is explored. High intensity pulses are used to induce acoustic streaming in cyst fluid, and this motion is detected using Do ppler techniques. Acoustic streaming cannot be generated in solid lesi ons, therefore, its detection would indicate a cyst. In six of seven b reast cysts motion was clearly generated and detected in vivo. Ultraso nic pulses with intensities up to 4.4 W cm(-2) (I-spta in water) were focused on the cysts for 10 s. Lesion diameters ranged from 0.6 to 2.5 cm; induced flow velocities were less than 4.0 cm s(-1).