Retrograde Pyelography (RGP) is performed by the urologist when other examinations (such as CT scanning) do not provide sufficient answers, or when intravenous contrast cannot be used (e.g. due to allergy or renal impairment).
It is a specialised imaging examination of the ureters and the kidney cavities:
- For the precise localisation and cause of an obstruction in the ureter (e.g. from strictures, tumours, or radiopaque/non-radiopaque stones)
- Before surgical procedures on the kidney or ureter, to fully understand the exact morphology of the area
- When there is blood in the urine, requiring a detailed check of the ureter and kidney walls for suspicious lesions
It offers exceptionally clear images of the kidney’s drainage system, bypassing any issues caused by reduced kidney function.
How the Examination is Performed
It is called retrograde pyelography because the contrast fluid moves opposite to the natural flow of urine, i.e. from below upward.
For the examination, the urologist inserts a thin cystoscope through the urethra into the bladder under mild sedation or anaesthesia. He locates the opening of the ureter and carefully advances an extremely thin catheter (ureteral catheter) upward, reaching the kidney. Contrast medium is injected directly through this thin tube. As the fluid fills the ureter and the renal pelvicalyceal system, continuous X-ray images are taken, capturing the anatomy and any pathological changes with exceptional clarity.
The examination is often combined with other diagnostic or therapeutic procedures, such as stent placement.
