Retrograde pyelogram


A retrograde pyelogram is a medical imaging procedure in which a radiocontrast agent is injected the ureter in order to visualize the ureter, bladder, and kidneys with fluoroscopy or radiography, using plain X-rays. The flow of contrast is opposite the usual outbound flow of urine, hence the retrograde name.
A retrograde pyelogram my be performed to find the cause of blood in the urine, or to locate the position of a stone or narrowing, tumour or clot, as an adjunct during the placement of ureteral stents. It can also be used ureteroscopy, or to delineate renal anatomy in preparation for surgery. Retrograde pyelography is generally done when an intravenous excretory study cannot be done because of renal disease or allergy to intravenous contrast.
Relative contraindications include the presence of infected urine, pregnancy, or allergy to the contrast. Because a pyelogram involves cystoscopy, it may cause sepsis, infection or bleeding, and may also cause nausea and vomiting. The dye may also be toxic to the kidneys.
Before the procedure, a person is usually asked to complete a safety check assessing for potential risks, such as pregnancy or allergy. They may be asked to take an enema, and not to eat for some hours. An intravenous drip is inserted and a person is given some sedation before a cystoscope, which is a flexible tube, is inserted into the bladder via the urethra. Dye is usually injected during cystoscopy, which is where a flexible tube is inserted into the bladder and to the lower part of the ureter. Fluoroscopy, or dynamic X-rays, is typically used for visualization. The procedure is usually done under general or regional anesthesia.