Section 4--bioeffects in tissues with gas bodies. American Institute of Ultrasound in Medicine.

Several animal models have exhibited thresholds for petechial hemorrhage in lung within the current output of diagnostic ultrasound systems. In addition, thresholds for damage in the mouse intestine due to diagnostic pulses of ultrasound have been explored. The implications for human lung and intestinal exposure to clinical diagnostic ultrasound have not yet been determined. In this section, the data supporting the thresholds of petechial hemorrhage in these organ systems and the morphological observations will be reviewed. The potential mechanical mechanisms of damage to these organs due to diagnostic ultrasound also will be reviewed. Special attention will be given to the occurrence of inertial cavitation both in vitro and in vivo. The effects of ultrasound parameters, age, and species on the threshold for damage in animal models will be explored.