Ultrasonic detection of renal calculi: accuracy tested in an in vitro porcine kidney model.

Porcine kidneys containing human calculi of known size and composition were used to study the ability of ultrasound to localize intrarenal calculi. The study conducted in a blind fashion demonstrated that stones as small as 2 mm could be detected. The chemical composition was not related to the ability to detect the stone. Early trials in the operating room have been encouraging. The porcine kidney model is useful for training purposes.