Saudi Journal of Kidney Diseases and Transplantation

: 2008  |  Volume : 19  |  Issue : 1  |  Page : 20--25

Which is the Best Way of Performing a Micturating Cystourethrogram in Children?

Ola Ali Al-Imam, Nareeman Moh’d Al-Nsour, Samih Al-Khulaifat 
 Radiology Department, King Hussein Medical Center, Amman, Jordan

Correspondence Address:
Ola Ali Al-Imam
Radiology Department, King Hussein Medical Center, Amman


The Micturating Cystourethrogram (MCU) is a tough and stressful examination for patients and their parents as well as the radiologists and pediatric radiology nurses. Even though, it is one of the most commonly used fluoroscopic procedures in pediatric radiology practice, there is no definite agreement as to the best way to perform it, considering that this examination results in the children receiving a high dose of radiation to the gonadal region. This review was undertaken to determine the best way to perform the MCU in modern pediatric radiology practice.

How to cite this article:
Al-Imam OA, Al-Nsour NM, Al-Khulaifat S. Which is the Best Way of Performing a Micturating Cystourethrogram in Children?.Saudi J Kidney Dis Transpl 2008;19:20-25

How to cite this URL:
Al-Imam OA, Al-Nsour NM, Al-Khulaifat S. Which is the Best Way of Performing a Micturating Cystourethrogram in Children?. Saudi J Kidney Dis Transpl [serial online] 2008 [cited 2021 Sep 26 ];19:20-25
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The Micturating Cystourethrogram (MCU) is one of the most commonly performed fluoroscopic investigations in any pediatric radiology department, and accounts for 40% of all fluoroscopic procedures performed on children in Europe. [1] The MCU remains essential and a primary tool for the diagnosis and evaluation of infants and young children with many genitourinary disorders, and this procedure is used to obtain specific diag­nostic information not already provided by other imaging modalities. The MCU demons­trates anatomy of both the bladder and urethra and the presence or absence of vesicouretral reflux (VUR); it also provides information about the function and co-ordination of the bladder and urethral sphincter. [2] It remains the investigation of choice for delineating the anatomy and determining the function of the lower urogenital tract.

The MCU is indicated in the investigation of patients with a wide variety of clinical conditions including urinary tract infection (UTIs), VUR, antenatal renal dilatation, congenital renal anomalies, posterior urethral valve (PUV), bladder neck trauma, hypos­padias, cloacal abnormalities and bladder diverticula. [3]

Undoubtedly this examination is an un­pleasant experience for patients, parents and radiology staff performing the test. It has been cited as being a more highly distressing investigation than several other invasive procedures performed on children. Unfor­tunately it is also an examination for which there are no recognized standard protocols. [4]

The purpose of this paper is to identify ways in which pediatric radiologists can adjust their protocols and techniques in order to obtain the best results needed.

 Patient and Parents Preparation

No physical preparation is necessary. However, the fact that this examination uses radiation and requires urethral cathe­terization can cause great anxiety in parents and their children. Children have a fear of both pain and the unknown and for these reasons, psychological preparation of both the parents and the child is mandatory. [2] The MCU remains the most distressing urinary radiological investigation experienced by our pediatric patients. [5] Thus, individuals who perform the MCU are responsible for doing all they can reduce the levels of distress and anxiety to the maximum extent possible. [3]

Patient and parent preparation can be in many forms; an explanatory pamphlet provided to the parents and children prior to the procedure describing the technique and explaining efforts to assure comfort and safety, in non-medical terms, can be useful. [2] Parental influence on the child during inves­tigation is an important factor that decides the degree of fear and anxiety induced by the MCU. Further benefit can thus be obtained by reducing the anxiety in the parents which will in turn reflect on the child's condition. Unexpected stress is obviously more anxiety provoking and difficult to deal with than anticipated or predicted stress. The evidence therefore shows that proper mental preparation of the patients and parents (especially in the younger patient group) can lead to a significant reduction in perceived anxiety and stress levels. [5],[6],[7] Preparation has also been shown to reduce the incidence of post-procedure anxiety which can manifest itself as excessive crying and withdrawal. [5]

Just before the actual examination, the procedure should be explained again to both the parent and the child using words and pictures; also, questions should be encou­raged. The child should be told repeatedly that there would be no surprises. [2]

During the procedure the parent should be encouraged to join in with the use of dis­tracting techniques. These have been shown to reduce stress and help the child cope with the situation. [7]

 Contrast Medium

A low osmolar contrast medium (150-160 mgI/ml) is perfectly adequate for pediatric MCU examination. This is what is usually used at our department in The King Hussein Medical Center, Amman, Jordan.

The contrast medium should be warmed to body temperature as it causes signifi­cantly less distress than cold medium. It does not prolong screening time or increase the volume of contrast required. [4] Other studies have shown that the detection of VUR was unaffected by the temperature of the contrast medium in children with previously diagnosed VUR as well as and in those being studied for the first time. [8]

Temperature receptors located within the mucosa of the bladder wall and trigone are responsible for a very sensitive cooling reflex. The infusion of iced liquid ( [8] This test is generally positive during the first four years of life but is typically negative in children older than five years. [9]

The estimated volume of contrast medium to be given during the examination is deter­mined mainly by the age of the child except for children less than one year of age in whom it is determined by weight: [10]

Less than one year,

Weight (kg) × 7 = capacity (ml)

Less than two years,

(2 × age in years + 2) × 30 = capacity (ml)

More than two years,

(Age in years/2 + 6) × 30 = capacity (ml)

Contrast medium is given by hand injection slowly to prevent transmucosal absorption and consequent contrast reactions. It should be noted that contrast maybe also given via the gravity drip method.


Prior to starting the procedure, it should be ensured that the child should has received the appropriate dose of antibiotic (one day prior to the examination and should continue three days after). The procedure should not be performed if the child has active UTI. However, the presence and grade of VUR is not influenced by the timing of the MCU one week after acute symptomatic UTI; [11] it can be safely performed in individuals known to have hyper sensitivity to contrast media

MCU should be performed under fluoros­copic guidance with the child awake. [2] The nurse will lay the child on the fluoroscopic table and the parent is asked to stand at the top of the table and hold the child's hand. Urethral catheterization should be done on the table using strict aseptic technique, after proper cleaning of the interlabial area or penile tip (the labia should be kept separated to avoid contamination). To facilitate easy introduction, gel is applied to the tip of the 8-Fr catheter (feeding tube) in all children except small premature infant when 5-Fr is substituted. [3]

The catheter is not advanced any further than 1-2 cm after urine is obtained, which can be placed in a sterile container for culture if required, and then the catheter is secured by taping it to upper inner thigh in girls. In boys, one piece of tape on the penis and the other on the right thigh will facilitate proper view of the urethra in the right lateral oblique position. [3]

The feeding tube is used in this examination because cyclical voiding is required; i.e. to refill the bladder multiple times and allow the child to urinate while the catheter is still in. VUR can occur intermittently and there­fore may not occur on a single void. [12]

One of the main reasons for performing the MCU is to detect VUR. Obtaining a second voiding cycle has been shown to increase the detection of VUR significantly; also, second cycle void can also increase the grade of reflux that was detected on the first void. [12],[13] Detecting the grade of reflux is of vital importance to plan appropriate treatment. Prone positioning has not been shown to enhance detection of VUR as did multiple studies performed with the patient supine. [13]

The duration of fluoroscopy should be kept to minimum and low-dose technique should be used whenever possible. [2] The gonadal radiation dose received by children undergoing MCU can be as high as 309 mRad in boys and 1,900 mRad in girls. [14] The risk of developing leukemia at this radiation does is calculated at 7-9 cases per 10 million children examined.

With recent advances in fluoroscopy, dose reduction can be easily achieved without any perceived loss of image quality. [15],[16]

Radiation exposure in pediatric fluoroscopy can be reduced to values well below the exposure settings that are typically found on un-optimized fluoroscopes. Pulsed fluoros­copy is considered a requisite for optimal pediatric fluoroscopy. [17]


Intermittent screening should take place throughout the study; most departments obtain 4-6 spot images. The spot films taken during fluoroscopy varies between different institutions and also between individual radiologists in the same institution. [1]

The following images should be obtained during examination:

Control film is obtained including the symphysis pubis to confirm the presence of radio-opaque shadow in bladder or urethra.Early filling view of the bladder reveals uretrocele, which may become obscured as the bladder fills with contrast media; any abnormalities of the bladder contour are noted. The initial filling is monitored by fluoroscopy in case the catheter is in the distal ureter (thereby mimicking VUR) or vagina. [18] Full bladder view: The excepted bladder capacity in ml for children is calculated with the formula mentioned earlier. This view is to document the bladder wall appearances at bladder capacity. [3] Voiding urethra view. In boys, it should be obtained by turning him to the right or left anterior oblique position while in girls, the view is obtained in supine position. Taking this view with the cathe­ter in may mask the appearances of posterior urethral valve (PUV). Obtaining urethral-free image in boys is unnece­ssary unless there is significant diagnostic doubt as to the presence of valves on the "catheter-in" image. [19] Full-length view of the abdomen is taken to demonstrate any reflux of contrast medium that might have occurred un­noticed into the kidneys and to record the post-void residue. [18] Children under one year of age do not empty their bladder completely. [20]

The last three images should be repeated as part of cyclical voiding study.


Complications arise usually from catheterization or rarely, absorption of the contrast medium. They include:

Catheter trauma may produce dysuria, frequency, hematuria and urinary reten­tion which occur in the first 24 hours after the examination. These effects can be kept to a minimum by encouraging the child to drink a large volume of fluids and to micturate in a warm bath. [18] Acute urinary tract infection, which can be avoided by covering the child with antibiotics as mentioned earlier. [21] Catheter maybe inadvertently placed in the vagina or via the uretrovesical junction into the ureter, or into uretrocele. [22] Perforation of the bladder may also occur, although is exceedingly rare and usually confined to patients with chronic renal failure or unused bladder. [3] Adverse reaction may result from absorp­tion of contrast media through the bladder mucosa. [1]


One of the major causes of impaired renal function and hypertension in later life is VUR, and MCU has been proved to be the investigation of first choice in the diag­nosis of VUR as well as a wide variety of clinical conditions.

This review has been written based on our own practical experience as well as literature review in order to illustrate the best and most appropriate way to perform the MCU with minimal distress and com­plication to both child and parent.


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