Ultrasonic differentiation of renal pelvic filling defects.

We herein describe 9 patients with non-opaque calculi and 3 patients with soft tissue filling defects in the renal pelvis studied by ultrasound. The calculi varied in size from 1.5 cm. to staghorn calculi. All stones were imaged satisfactorily by ultrasound, allowing the diagnosis of stone to be made with confidence. Ultrasonic differentiation of renal pelvic filling defects proved to be a simple, reliable, non-invasive method to differentiate these clinically perplexing lesions.