Rx ascending / descending pyelography
When is this exam indicated?
The examination allows an accurate morphological analysis of the upper urinary tract and allows the performance of ureteral lavage and the collection of urine samples for cytological and/or cultural investigations. It is usually prescribed by the physician to investigate the presence of stenosis of the ureter, which is evidenced as an interruption/restriction of the progression of the contrast medium, and lithiasic or tumor pathologies, which may manifest as defects in filling of the excretory system. Furthermore, this technique can be used to study the outcome of demolition and/or reconstructive surgery, to evaluate the ureter patency and to exclude the presence of post-operative fistulas.
How is it performed?
In the case of ascending (or retrograde) pyelography, a cystoscope is initially inserted, allowing the bladder to be reached and the ureteral ostium to be cannulated with a guide wire and ureteral catheter. Then, contrast agent is injected inside the ureteral catheter and fluoroscopic images are acquired to opacify the ureter and kidney.
The descending (or anterograde) pyelography is based on the same principle, but it uses the introduction of contrast medium through a percutaneous nephrostomy, when ureteral cannulation is impossible (e.g. in case of impossibility to identify the ureteral ostium) or the patient already has a nephrostomy, in order to opacify the kidney and ureter.
The only contraindication may include an allergy to the contrast medium. In these cases, the patient can be prescribed medication to prevent allergic reaction.