Special Procedure: Intravenous Urography
Intravenous Urography (Pyelography) is a progressive radiographic study done after the intravenous injection of an iodine contrast agent which allows visualization of the kidneys, ureters, and limited information on the urinary bladder. The procedure uses multiple radiographs at a particular sequence thus showing contrast enhancement of the renal vasculature (vascular phase, sometimes not acquired), renal parenchyma (nephrogram phase), renal collecting system, and ureters (pyelogram phase) as contrast medium is excreted by the kidneys and passes through the renal collecting system, ureters, and into the urinary bladder.
Indications for this procedure :
- Evaluate the size, shape, and position of the kidneys, ureters and bladder.
- Investigate the cause and source of hematuria and pyuria when the bladder is not believed to be the source.
- Suspected calculi or masses involving the kidneys or ureters.
- Urinary incontinence, particularly if ectopic ureters are suspected.
- Determine the effect of retroperitoneal or intraabdominal masses on the structure, position and function of the urinary tract.
- Evaluate the result of trauma to the urinary tract, particularly to assess for tears in the ureters.
- Qualitative assessment of renal function and patency of the urinary tract.
- Postoperative assessment of the urinary tract.
Contraindications and complications for this procedure :
- Anuria (absence of urine production).
- Severe dehydration.
- Uremia is not a contraindication as long as the patient is hydrated and producing urine. However, the diagnostic quality of the study may be compromised because of poor contrast concentration.
- Known allergy to iodine is an absolute contraindication.
- Vomiting is a common side effect that is generally self-limiting.
- Allergic reactions include urticaria, hypotension and bronchospasm.
- Contrast medium-induced renal failure is a rare, idiosyncratic reaction.