Acoustic streaming: an in vitro study.

The aims of this study were, first, to determine if cyst size and cyst-to-transducer distance have an impact upon acoustic streaming and, second, to investigate the effect of cyst content viscosity on acoustic streaming using an artificial ovarian cyst model. Artificial ovarian cysts were constructed and suspended in a tissue-mimicking bath. Although there was no subjective difference in acoustic streaming velocity between cyst sizes during B-mode insonation, with colour Doppler and pulsed Doppler examination, higher acoustic streaming scores were recorded for larger cysts. When the cyst-to-transducer distance was increased, the acoustic streaming velocity was noted to decrease in all scanning modalities. The second stage of the study demonstrated decreasing acoustic streaming velocity as the viscosity of the cyst content was increased. The finding of a clear association between cyst content viscosity and acoustic streaming velocity raises the exciting possibility that we may be able to make estimations of the viscosity of ovarian cyst contents, in the clinical setting, by sonographic means.