Urography is a contrast-enhanced X-ray examination to visualize the entire urinary system. From the kidneys via the urinary tract to the urinary bladder. As a rule, iodine-containing drugs are used as a contrast medium. Depending on how the doctor administers this contrast agent to the patient being examined, two types can be distinguished:
- excretory urography and
- Retrograde urography
In excretory urography, doctors administer the contrast agent as an injection or infusion into the bloodstream via a vein. The kidneys, ureters, bladder and urethra then excrete it again.
In retrograde urography, on the other hand, doctors introduce the contrast agent directly into the organs to be examined. This is done using a catheter. The areas examined are the bladder, the ureters and the renal pelvis.
With retrograde urography, only a morphological examination (shape and structure) is possible. With excretory urography, on the other hand, doctors can also examine the function of the urinary tract.
Indications for performing a urography
A contrast-enhanced X-ray examination of the urinary tract makes it possible to visualize the inner contours of the kidneys, renal pelvis, ureter and bladder.
The following symptoms and complaints can be clarified:
With the help of urography, doctors can clearly diagnose the following diseases of the urinary system :
- Kidney stones or bladder stones
- Malignant tumors of the kidneys or urinary tract such as kidney cancer or bladder cancer
- Constrictions in the kidneys or urinary tract
- Congenital malformations of the ureters or kidneys
- Injury-related tears in the renal pelvis
Kidney stones are urinary stones and are deposits that form from components of the urine @ airborne77 /AdobeStock
Contraindications for performing a urography
The examination is not suitable for patients with:
In these cases, the iodine in the contrast medium leads to complications. These disorders may also speak against this examination:
- Renal dysfunction
- Heart muscle weakness
- Pregnant women
In these cases, the doctor must weigh up the risks and benefits of the examination.
Before the examination, the patient should inform the doctor about
- Any medication taken
- Previous operations
- Known allergies to contrast agents or other substances in order to prevent possible complications
The patient does not need to be fasting for an excretory urography. However, they should not eat or drink anything for at least three hours beforehand.
The patient only needs to fast for a retrograde urography if the examination is performed under general anesthesia. It may be necessary to take a laxative or anti-bloating agent in preparation for the examination. In this way, distended bowel loops do not prevent the urinary system from being seen.
During the examination, doctors take an average of three to four x-rays of the abdominal cavity. Usually while the patient is lying on their back.
The first X-ray is taken before the patient receives the contrast medium. Further X-rays are taken 3 to 10 minutes and 20 minutes after the contrast medium has been administered. A further image is taken when the patient has excreted the contrast medium from the urinary tract (excretory urography) (retrograde urography).
During excretory urography, the doctor injects the water-soluble, iodine-containing contrast agent into the patient's arm via a vein. An infusion is also possible.
From there, it reaches the kidneys via the bloodstream. The ureter, bladder and urethra excrete it again.
In retrograde urography, the examination is carried out using a catheter that doctors insert through the urethra into the bladder. Doctors inject the contrast agent directly into the organs to be examined (urethra, bladder, ureter and renal pelvis) via the catheter.
For urography, the doctor uses a contrast agent to better recognize the anatomical structures @ samunella /AdobeStock
The possible complications of a urography are
- Injuries to the urethra, bladder, ureter and kidney: these can be caused by the catheter itself or by the pressure of the contrast medium, for example.
- Excretory urography can lead to damage, infections or scars at the insertion site and on the vein.
- In some cases, kidney function may be temporarily impaired after the examination. However, serious damage to the kidneys is very rare.
- It is also possible that the patient may have an allergic reaction to the injected contrast medium. Only in rare cases does an allergic reaction lead to life-threatening complications or damage to important organs.
