Ultrasonic imaging of microscopic structures in living organs.

It is possible to estimate acoustic parameters that describe the microscopic anatomy of live tissues. The same rf echo signals used to form diagnostic ultrasound images undergo additional signal processing to compute D, the average scatterer size; SNR, a measure of the number density of scatterers; and IBC, a measure of tissue echogenicity. With these three parameters it is possible to identify the sources of ultrasonic scattering in kidneys, observe functional changes in live organs, and produce images of each parameter. Although this chapter has emphasized the more basic research elements of possible applications, similar methods have been used to study changes in tissue morphometry during the progress of disease and during the course of therapy in several organ systems. Advances in diagnostic ultrasound are providing safe and low-cost method for studying soft tissues in vivo.