Kids Health Info

Micturating cysto-urethrogram (MCU)

  • Micturating cysto-urethrogram (mick-cha-rating sis-toe you-reeth-row-gram), or MCU, is a fluoroscopy examination to look at the function of the bladder and urethra. Fluoroscopy uses X-rays to create a moving image of internal parts of the body.

    The test is not painful, and it takes about 30 minutes. An ultrasound examination (which also takes about 20 minutes) may need to be done first. 

    Why does my child need an MCU?

    An MCU may be performed for different reasons, including to:

    • check the structure and functioning of the bladder or urethra
    • diagnose, treat and manage diseases
    • monitor response to treatment.

    What to expect with an MCU

    Before the MCU

    No preparation is required for the MCU, but other tests done at the same time (e.g. an ultrasound or nuclear medicine study) may require special preparation. If this is the case, you will be given instructions to follow.

    To help distract your child and keep them occupied before and during the procedure, you may wish to bring your child’s favourite toy, electronic device or book to the appointment.

    When you arrive, your child will be changed into a hospital gown. A doctor or nurse will describe the procedure to you in detail and you will be asked to sign a consent form. You will both then be taken to the fluoroscopy room where your child will lie on their back on the examination table.

    During the MCU

    The first part of the examination is inserting a catheter into your child’s bladder via the urethra (the hole where urine comes out). You can stay with your child during this procedure, and you may be asked to help keep them still.

    • The doctor will wash the skin around the urethra with a sterile solution.
    • A soft plastic catheter (tube) coated with lubricant gel is then inserted into your child’s bladder. This can feel uncomfortable while it is going in, but it should not hurt. Once the catheter is in place it should not be uncomfortable, and it will be taped into place.
    • The bladder will then be filled with contrast dye, which is run in through the catheter.

    The fluoroscopy camera will move around your child. Although it will come quite close, it will never touch them. Images will be taken from different angles and your child will be placed into different positions. Your child must remain still while the images are being taken.

    You may be asked to stay and help hold and comfort your child; however, if there is any chance the parent or carer might be pregnant, they cannot remain in the room during the X-ray examination.

    For the test to be complete, it is very important that your child passes urine into a dish or a bottle while lying on the X-ray table - images will also be taken at this time.

    At the end of the procedure the catheter tube will be removed.

    After the MCU

    After the MCU, your child will be observed for an hour before they will be able to leave. It is extremely rare for complications to occur after the MCU, because the contrast is introduced into the bladder and urinated straight out again.

    The referring doctor will receive the report of the examination within a couple of days. If you have any questions about the results of the MCU, speak to your doctor.

    Key points to remember

    • An MCU is a fluoroscopy examination that is used to look at the bladder and urethra.
    • Your child will have a catheter inserted, and their bladder will be filled with contrast dye.
    • Ideally, a parent or carer will stay with the child during the test and help keep them still. Anyone who is pregnant will not be able to stay in the room for the test.
    • For the test to be complete it is very important that the child pass urine while they are lying on the X-ray table.

    For more information

    Common questions our doctors are asked

    My child is very anxious about medical procedures and I am worried he won't stay still for the MCU. How can I help him?

    To get some ideas of how to talk to your child about the appointment before you come to hospital, see our fact sheet Reducing your child's discomfort during procedures. You can also download our Okee in Medical Imaging app, which includes games and information especially designed to help children feel more comfortable about having medical imaging done at the RCH, and includes fun training on how to keep still.

    Are there any side effects of the contrast dye?

    It is extremely rare for a child to have an allergic reaction to the dye used in an MCU. In the event of a reaction, specially trained staff will be on-hand to manage any symptoms. The dye does not cause any long-term complications.

    Why did staff ask if my 12-year-old daughter could be pregnant?

    We understand this is a sensitive, and sometimes shocking, question to have your child asked. The RCH follows the advice of the Australian Radiation Protection and Nuclear Safety Agency, which recommends asking the pregnancy status of female patients who are of childbearing age and undergoing imaging that includes the uterus (e.g. X-rays of abdomen, pelvis, lumbar spine). This is to make sure that any possible unborn babies are not exposed to a unsafe radiation dose.

    Children vary greatly in their development, and some preteen females are developed enough that they could become pregnant. To make sure it doesn't appear to be a judgement on the individual, the RCH has made it a rule to ask any female aged 12 and over whether they could be pregnant. We do our best to approach the question sensitively and are always happy to answer further questions from parents or patients.

    Will I need to wear a lead apron during my child's X-ray?

    If you are required to calm your child during their X-ray, or hold them in a specific position, you will be offered to wear a heavy apron made of lead, to minimise your own radiation exposure. It is very important that you tell the radiographer if you are – or may be – pregnant.

    Developed by The Royal Children's Hospital Medical Imaging department. We acknowledge the input of RCH consumers and carers.

    Reviewed October 2018.

    Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit

Kids Health Info app

The app will enable you to search and browse more than three hundred medical fact sheets and work offline.

Apple store Google play

This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital, Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.