A renal bladder ultrasound is a noninvasive diagnostic imaging study to assess the kidney, ureters, and bladder. Referred to as “jelly on the belly” this painless examination is the most commonly used imaging modality for children with urinary system concerns. Ultrasound, or sonogram, exposes the body to sound waves, which are reflected off tissues and organs to produce images onto a screen. No ionizing radiation is used with ultrasound.