3. Urinary collecting system IVU, AP projection

This is a film from an intravenous urogram (IVU). The dial projecting over the left femur indicates that this image was obtained 25 minutes after the injection of intravenous contrast into a peripheral vein. The contrast — a sterile, water soluble liquid containing iodine — is filtereed from the blood by the renal glomeruli, and becomes more concentrated in the renal tubules as most of the filtrate is reabsorbed. It becomes so concentrated in the urine that it casts the radiopaque shadows seen here, allowing us to visualize all parts of the urinary collecting system from minor calyces to bladder.

This study is also called an Intravenous Pyelogram (IVP). "Pyelo" is the combinational form for "pelvis."