Intravenous urography, or IVU, was previously one of the most commonly performed investigations in urology. Its primary use is to demonstrate the anatomy of the urinary tract.
An iodine-containing contrast medium is given by intravenous injection. Non-ionic media are preferred as they are less hazardous than the older, ionic media.
A series of abdominal radiographs are taken at the time of injection, at measured times afterwards, and after the patient has voided. As the contrast is excreted, the renal parenchyma, renal pelvis, ureters and bladder are outlined in order. The post-voiding film allows assessment of residual volume.
Delayed films may be required when upper tract obstruction or slow opacification of the collecting system is present. Films may be taken at 1, 2, 4, 8 or 16 hours etc. after the initial injection of contrast.
Frusemide may be given to assess clearance in cases of equivocal pelvi-ureteric junction obstruction.
A crude assessment of renal function is gained from the speed at which contrast is excreted.
Last reviewed 01/2018