No effect of prolonged pulsed high frequency ultrasound imaging of the basilar membrane on cochlear function or hair cell survival found in an initial study

Miniature high frequency ultrasound devices show promise as tools for clinical middle ear and basal cochlea imaging and vibrometry. However, before clinical use it is important to verify that the ultrasound exposure does not damage the cochlea. In this initial study, electrophysiological responses of the cochlea were measured for a range of stimulus frequencies in both ears of anesthetized chinchillas, before and after exposing the organ of Corti region of one ear to pulsed focused ultrasound for 30 min. Measurements were again taken after an 11 day survival period. Cochlear tissue was examined with a confocal microscope for signs of damage to the cochlear hair cells. No significant change in response thresholds due to exposure was found, and no signs of ultrasound-induced tissue damage were observed, although one animal (out of ten) did have a region of extensive tissue damage in the exposed cochlea. However, after further analysis this was concluded to be not likely a result of the ultrasound exposure.