Unfocused ultrasound for localized tissue destruction in rabbit kidneys.

The rabbit kidney was subjected to exposure from an unfocused ultrasound source in an effort to create a relatively large volume of ultrasound-damaged tissue in the rabbit kidney. The results of this exposure were followed for 1 year. An insignificant change in blood pressure was noted up to 1 month after exposure to ultrasound and no persistent hypertension was noted thereafter. Marked gross, histologic, and vascular changes were found in the area of exposure culminating in marked absorption of renal substance (in excess of 25 per cent of total kidney weight). Calcific stones formed in the pelvis of the kidney in virtually all animals observed from 6 months to 1 year after ultrasound exposure. These stones appeared to be related to the calcification within the transitional epithelium of tubules at the junction of normal and ultrasound-damaged tissue. The marked ability of the absorptive processes to ablate large volumes of physically damaged tissue is demonstrated.