The cystogram (synonyms: cystography; urinary bladder x-ray), the x-ray examination of the urinary bladder, is a diagnostic procedure in urology that can be used to assess the anatomical location and shape of the urinary bladder. It can also be used to rule out various pathological findings, such as neoplasia (benign or malignant neoplasm of tissue) or diverticula and foreign bodies.
Indications (areas of application)
- Carcinoma of the urinary bladder – this tumor may be detected by various cystography methods. To determine whether the tumor is a benign or malignant neoplasm, a biopsy (tissue sample) must be taken during cystoscopy (bladder examination).
- Diverticula – protrusions in the wall of the urinary bladder cause altered filling of the bladder, so cystography can sensitively detect diverticula.
- Foreign bodies – if there are foreign bodies in the urinary tract, they can be visualized with the help of cystography.
- Vesicoureteral reflux – evidence of pathological reflux in children is particularly common after an acute urinary tract infection. Cystography should also be used during necessary check-ups of children with reflux symptomatology.
- Follow-up – after surgery or an endoscopic procedure has been performed, cystography can be used to assess the results.
Contraindications
- Descending kidney – the presence of a descending kidney (low-lying kidneys or pelvic kidneys) should be considered a relative contraindication, since the detection of reflux is almost impossible due to the insufficient distance between the kidney and the urinary bladder.
- Acute urinary tract infection – due to the inflammation of the tissue, there is a possibility that contrast agent is absorbed by the bladder tissue and can lead to secondary damage. In addition, the risk of false positive results is significantly increased.
Before the examination
Contrast agent allergy – before the X-ray examination can be performed, it is essential to rule out an allergic reaction to the contrast agent to be applied, as the presence of an allergy can lead to life-threatening allergic shock, for example.
The procedure
However, to evaluate the urinary bladder, it is necessary for it to be filled with contrast medium in order to visualize changes in the tissue during an X-ray examination. Visualization of the urinary bladder by x-ray examination:
- Retrograde cystography – in this variant of X-ray examination, the contrast medium is applied into the urinary bladder with the help of a catheter. Before the catheter is inserted, disinfection of the urethral opening (outer end of the urinary tract) is performed to prevent possible secondary infections. After the catheter is inserted, an infusion of a contrast agent containing iodine is connected. After the application of the contrast medium, a small balloon is filled with air to seal the urinary tract, so that the actual examination can then begin.To achieve an optimal assessment of the urinary tract, X-rays are taken during the examination in the standing and lying position. To prevent false positive results, the choice of contrast medium is of crucial importance, as various contrast media can be absorbed by the bladder wall. In particular, if damage to the bladder wall is present as a result of inflammation, the risk of absorption is especially increased. The consequence of this unwanted absorption is the transfer of the contrast medium into the bloodstream and excretion of the contrast medium by the kidney. Thus, if the contrast agent is stored near the urinary tract, false positive results can be produced.
- Intravenous urography – this procedure, also known as excretory urography, is characterized by the fact that the patient does not receive a catheter for contrast agent application, but instead is administered the contrast agent via intravenous access to visualize the urinary tract and urinary bladder.
- Micturition cystourethrography (MZU) – with the help of this procedure, the physiological process of micturition can be recreated, so that a review of the function becomes more feasible.Analogous to retrograde cystography, a retrograde (from the external opening of the ureter in the direction of the urinary bladder) filling of the urinary bladder with contrast medium is first performed. To improve the validity of the procedure, it is possible to combine micturition cystourethrography with a video-based recording method. This combination is also called videourodynamics and is currently the method of choice in a review of micturition.
- Expression urethrography – this procedure plays an important role in the evaluation of pathologic processes in the urinary tract in both infants and young children. In contrast to the procedures described so far, expression urethrography is performed exclusively under general anesthesia. As a rule, urethrography can be followed by cystography without significant additional stress on the infant’s organism. After cystography, the urinary bladder contents are expressed by manipulation so that the contents move through the urethra. Thus, through the application can be not only an assessment of the urinary bladder but also the urethra.
- Polycystography – this method involves imaging of the urinary bladder with contrast instillation (administration of the contrast agent) in varying states of filling and emptying.
- Indirect radionuclide cystography – this method is used to confirm vesicoureteral reflux. However, a special feature of the method is that, in contrast to retrograde cystography, for example, no catheterization is necessary. Thus, an assessment of the micturition phase is possible under physiological conditions. In addition to the absence of a catheter, the procedure also has the advantage of higher sensitivity (percentage of diseased patients in whom the disease is detected by the use of the test, i.e. a positive test result occurs) compared to retrograde cystography in various clinical studies.
Imaging of the urinary bladder by sonography (ultrasound):
- Regardless of the field of application of sonography, this method has the advantage compared to conventional X-ray examination that it does not lead to radiation exposure.
- As another advantage of sonography is also the spatial resolution, which is superior to that of the radiological method. Meanwhile, a disadvantage is that dynamic monitoring of the filling and micturition phase simultaneously in both ureters and kidneys is not possible with sonography. Furthermore, the use of direct ultrasound contrast cystography requires the use of a bladder catheter, so there is a higher risk of complications in the form of infections and lesions in the urinary tract.
Possible complications
Since this is a non-invasive diagnostic procedure with little physical stress, there are almost no known complications. However, contrast allergies may occasionally occur, which can be associated with massive and sometimes life-threatening symptoms. Furthermore, the patient’s renal function must be intact (determination of creatinine clearance, if necessary) to ensure that the contrast medium can be excreted.
