What is micturition ultrasonography?Micturition ultrasonography is a special ultrasound diagnostic of urinary tract and kidney using contrast media.
The term urology (MUS) includes voiding (emptying the bladder), urology (medical specialty dealing with urinary organs) and sonography (ultrasound examination of organs). The purpose of the study, which is often performed in children, is to use contrast media to diagnose a vesico-uretero-renal reflux (VUR), ie the return of the urine from the bladder via the ureters to the kidney.
It supplements classical examinations such as normal ultrasound diagnostics and laboratory diagnostics, for example the examination of urine for germs and special blood tests. In order to record the physiological processes in the urinary tract of the patient not only as a snapshot but also with regard to the functional activity, the examination is also performed during the urination or the subsequent refilling of the bladder.
Frequently, the visualization of a possible VUR is performed by means of color-coded Doppler ultrasound, as here the course of the contrast agent can be represented very precisely and in this way a very accurate diagnosis can be made.
Function, effect & goals
If children suffer from a urinary tract infection that accompanies fever, it is suspected that the kidney is involved in the disease. This is due to germs that enter the kidney via an unphysiological reflux of urine from the bladder. This reflux may be due to congenital anatomical disorders (primary VUR), but may also be due to acquired defects such as sequelae, inflammation or urinary tract disorders (secondary VUR).
In order to prevent kidney damage caused by common diseases of this kind, a possible reflux is promptly determined. Since conventional sonography can not do this alone, the diagnostic accuracy of micturition ultrasound is greatly improved. At the beginning of the examination, a thin catheter is inserted into the bladder and a conventional ultrasound of the condition of the kidney and urinary organs is carried out on the usually slightly sedated patients. Subsequently, the bladder is filled with a body-warm physiological saline solution and added the necessary contrast agent for presentation.
Already at this point, the Miktionsurosonografie under some circumstances already provide important information: If here already a back flow of the contrast medium enriched liquid to recognize, can be assumed by a Niederdruckreflux, ie a reflux already at bladder filling. In the further course of the examination, the movement of the contrast agent during the micturition is observed sonographically. If urine flows back to the kidneys, it is called a high-pressure reflec- tion, because the pressure inside the bladder increases during urination. Sometimes it is important for a reliable diagnosis assurance to check the process of filling and emptying the bladder in the Miktionsurosonografie several times.
In the same study, it is also possible to fill the bladder with air to see if air bubbles are rising into the kidney region. With the investigation can not be assured beyond all doubt, if there is a reflux. Due to the lateral separation of the function of ureter and kidneys - in contrast to laboratory investigations - the area responsible for the reflux can often already be recognized. The informative value of micturition ultrasound with regard to the VUR is very high, especially when observing multiple micturations and when using a color Doppler.
However, in the case of a non-clinical examination, it is advisable to consistently examine the urine for bacterial load in the event of further urinary tract infections with fever and, if necessary, to carry out the micturition ultrasound again with the question of a reflux. The benefit of preventing kidney damage is usually greater than the inconvenience associated with this examination.
Risks, side effects & dangers
The risks of micturition ultrasonography are - especially in comparison to otherwise possibly overlooked renal hazard from a possible reflux - low. Compared to the alternative diagnosis, the micturition cystourethrography (MCU), the MUS even offers a clear advantage: in contrast to the MCU, which also sends X-rays to the reproductive organs of mostly young patients, the sonographic variant of urological diagnostics comes without radiation out.
The ultrasonic waves used are absolutely harmless and can be used as often as desired. The contrast agent is usually well tolerated. In order to relieve children of the fear or discomfort of the somewhat unpleasant examination, a slight sedation is possible, which, as a rule, is also well tolerated. Until the calming drug has diffused out of the body, the child must be well watched, so that it does not contract, for example, by a slight restriction of the ability to coordinate.
Sedation also has the advantage of preventing injury to a catheterized patient when the catheter is inserted. A possible but rare side effect of micturition ultrasonography may be that, despite careful and correct disinfection, germs are introduced and the resulting urinary tract infection is the result. For this reason, it is important to pay attention to typical symptoms, especially fever, in the days after the examination. If an infection is suspected, a urinalysis should be carried out quickly and the necessary antibiotics administered to germs in the urine.