Heating as a mechanism for ultrasonically-induced petechial hemorrhages in mouse intestine.

摘要: Abstract Anesthetized hairless mice were exposed to 1.035 MHz unfocused ultrasound in a temperaturecontrolled water bath. Visible petechial hemorrhages and hyperemia produced the intestines. Histologically, petechiae appeared be localized mostly lamina propria of mucosa. For 2 min exposure, number length hyperemic tissue both increased with increasing spatial peak pressure amplitude above threshold about 0.4–0.57 MPa. The magnitude these effects increased, decreased, exposure duration from 1 4 min. also for bath temperature 32°C 42°C. decreased markedly ms burst-mode repetition periods constant amplitude, but essentially temporal-average intensity. Both by heating radio-frequency diathermy at 10.35 MHz. associated abdominal temperatures 42–43°C, which estimated thermocouple end exposure. is clearly thermal effect, while have been previously cavitation, mechanism. However, ultrasonically-induced observed this study do not represent an unequivocal marker rather appear attributable heating. These findings help reduce expectation ultrasonic cavitation during medical therapy treatments.