Interactions between human intestines and ultrasound have not been extensively evaluated. Decreases the acoustic pressure threshold for and increases the severity of cavitation bioeffects. Induction and sustenance of inertial cavitation activity. Even when encapsulate GCAs are present, inertial cavitation developes in generated free bubbles and fragments. Bioeffects increase as acoustic pressure increases and frequency decreases.
Much less hemolysis is produced at higher frequencies.
GCAs may enhance vascular damage. After the loss of significant contrast GCA's may continue to act as cavitation nuclei. The claims that the MI can predict thresholds in mammals for mechanical effects have not been validated. Underestimation of in situ exposure due to propagation through low attenuation media may cause errors.