Urethral X-ray (Urethrogram)

A urethrogram is a diagnostic procedure used in urology to assess the function of the urethra (urethra) and urinary bladder, which is performed using X-ray diagnostics. For better assessment of the anatomical structures, X-ray diagnostics is performed with a contrast medium, so that the lumina (openings) to be examined become more visible. Depending on the variant of the procedure, the examination is performed as a micturition dynamic examination, also known as a micturition cystourethrogram, or as a retrograde (backward) urethrogram. The aim of the procedure is to detect stenosis (narrowing) and, if necessary, complete obstruction of the urinary tract.

Indications (areas of application)

  • Radiographic examination (in this case, retrograde urethrography, RUG) of the male urethra for evaluation (evaluation) of trauma (injury), diverticula (wall protrusion), strictures (narrowing), or valves.
  • Urinary tract infection – with the help of micturition cystourethrography and retrograde urethrography, it is possible to detect a urinary tract infection associated with micturition disorders. In such a case, the procedure is a method of confirming the diagnosis.
  • Widening of the renal pelvis – widening of the renal pelvis indicates urinary dysfunction, so a urethrogram is usually made by X-ray diagnosis.
  • Bladder wall thickening – the presence of thickening of the urinary bladder wall primarily indicates an adaptive reaction of the tissue, which is stimulated by increased pressure to proliferate (cell proliferation). However, in addition to urinary retention, tumors can also be responsible for the thickening.
  • Vesico-ureteral reflux (synonyms: vesicoureteral reflux, vesico-uretero-renal reflux, VRR, VUR, vesicorenal reflux) – unphysiological reflux of urine from the bladder via the ureters (ureters) into the renal pelvis; in the case of a urinary tract infection, there is thus the possibility that infected urine runs back into the ureters into the renal pelvis. Micturition cystourethrography can be used to check whether urine is flowing back into the ureters both at rest and during micturition. The procedure used is to assess the risk of inflammation of the kidney due to reflux.

Contraindications

Allergy to contrast media – if an allergy is present, urethrography should not be performed under any circumstances because of the risk of allergic shock.

The procedure

Retrograde urethrogram (RUG).

  • The retrograde urethrogram is of great importance in radiologic imaging of both the male and female urethra. However, because no assessment is possible without the movement of a fluid, the procedure is one of the partial urodynamic diagnostic procedures. With the help of the creation of a retrograde urethrogram, it is possible to detect evidence of dysfunction in the urinary drainage area. Pathological changes that can be detected with the use of the urethrogram include, for example, short and long urethral strictures and urethral diverticula (bulges in the urethra). The consequence of these pathological changes is the development of clinical functional impairment of the lower urinary tract.
  • However, retrograde urethrogram represents a relatively complex procedure in both men and women. This is based in particular on the fact that in the male, air-free retrograde contrast administration and a seal of the meatus urethrae externus (external opening of the urethra) must be performed. In women, however, sealing is no easier, as both the meatus urethrae externus and the meatus urethrae internus (external and internal opening of the urethra) must be provided with flow prevention. In addition to the varying seal, the methods of implementation differ significantly in men and women.
  • In the male patient, a number of applicators are necessary when performing the retrograde urethrogram in order to use the procedure. The applicators used serve on the one hand to stretch the urethra, and on the other hand to seal the meatus urethrae externus. The seal is indispensable so that a complete and adequate contrast filling of the urethra (urethra) becomes feasible.
  • To ensure a meaningful examination of urinary outflow in female patients, a double balloon system must be used when filling the urethra (urinary tract) with contrast medium. With the help of this double balloon system, the urethra can be temporarily closed to the meatus urethrae externus. Furthermore, the use of this system leads to the safe prevention of a transfer of the contrast medium into the bladder. Due to the exclusive filling of the urethra, it is relatively stretched by the contrast medium, so that an optimal representation of existing pathological processes can be made.
  • However, it should be noted that a combination of the retrograde urethrogram with an additional urodynamic measurements such as micturition cystourethrogram is not feasible, because the retrograde urethrogram may not allow physiological micturition. However, the procedure can be used before an invasive method by means of an endoscope in order to avoid the minimally invasive measure, if necessary.

Micturition cystourethrogram (MZU).

  • With the help of micturition cystourethrography (synonym: micturition cyst urethrography, MCU), it is possible to recreate the physiological process of micturition and thus detect possible strictures or other pathological changes. At the beginning of the procedure, a transurethral (passing through the urethra) filling of the urinary bladder with contrast medium is performed. The use of the contrast medium is intended to simplify the assessment of the urinary tract and thus represents an important component of the X-ray examination.
  • If the micturition cystourethrogram is combined with a simultaneous recording method, a precise assessment of pathological processes in the lower genitourinary tract can be achieved, which also serves as the gold standard (method of first choice) in diagnostics. Simultaneous recording as video is also called videourodynamics. Although the procedure is used relatively often in pathological changes in the urethra, the examinations must still be repeated several times to obtain therapeutically useful results.
  • The preparation of the micturition cystourethrogram is usually performed in a sitting body position. However, the body position can be varied depending on the question. In order to obtain an overview of the bladder and urethra (urethra), the shape, position and, moreover, the function are observed by taking X-rays already during the filling of the bladder. Only when the bladder is completely filled and the micturition phase can take place, the micturition is examined with the help of various X-rays. By using different perspectives, a determination of the bladder function and a complete visualization of the bladder neck and the posterior urethra are possible. The closer the measurement method depicts the physiological micturition process, the better the results of the diagnostic procedure.

Possible complications