Results from a clinical study are presented, in which ultrasonically-induce
d acoustic streaming was successfully used to differentiate fluid-filled le
sions (cysts) from solid lesions in the breast. In this study, high-intensi
ty ultrasound pulses from a modified commercial scanner were used to induce
acoustic streaming in cyst fluid, and this motion was detected using Doppl
er methods, Acoustic streaming was generated and detected in 14 of 15 simpl
e cysts, and 4 of 14 sonographically indeterminate breast lesions, This les
ion differentiation method appears to be particularly suited for diagnosis
of small, possibly newer, cysts that appear indeterminate on conventional s
onography due to their size, The results indicate that this method would be
a useful adjunct to conventional sonography for the purpose of breast lesi
on classification. (C) 1998 World Federation for Ultrasound in Medicine & B
iology.