The ability to visualize renal cryosurgery using ultrasound was tested
in an animal model. Five dogs underwent open laparotomy and ultrasoun
d-monitored cryosurgery of both kidneys. On each kidney two cryolesion
s were made. The borders of the frozen region were identified on ultra
sound as a hyperechoic rim created by the interface between frozen and
unfrozen tissue. The thawed cryolesion appeared hyperechoic compared
with the unfrozen kidney. Excellent correlation between the ultrasound
and autopsy measurements of the cryolesions was obtained. Knowing thi
s, renal cryosurgery under ultrasound monitoring may be possible.