Kids Health Info

CT scan

  • CT stands for Computed Tomography. CT is also sometimes called a CAT scan. The CT scanner uses X-rays to create cross-sectional images of all or a part of the body.

    CT scans can be done for many different reasons:

    • To look at the shape or structure of parts of the body (anatomy)
    • To check for any signs of disease
    • To help plan follow-up treatment after a procedure
    • To help with planning before an operation.

    A CT scan can be done on any area of the body.

    What is involved with a CT scan?

    The CT scanner is a big open doughnut-shaped machine. Patients lie down on a table which is moved through the middle of the machine. Patients go in and out of the machine at least twice. The CT scanner takes all of its pictures as the table is moving. The patient needs to keep very still for the pictures and sometimes hold their breath; usually less than 10 seconds. Generally the CT scan study takes about 10-15 minutes, but the pictures are taken in only 5-10 seconds.

    Preparing for a CT scan

    Preparation for a CT scan depends on the body area that is being scanned.

    If your child is having an abdominal scan they may need to drink an oral contrast. This is a drink that helps the radiologist to see the stomach and intestines more clearly.

    Sometimes your child may need to have contravenous (IV) contrast by injection so the radiologist can clearly see blood vessels and organs in the body. If this is needed, your child can have a topical anaesthetic cream (called Angel or Emla cream) on their hand or arm first. This will make the area numb so they are less likely to feel the injection. The Angel cream usually takes 30-60 minutes to work.

    Because every child is different, the radiologist may need to decide either before or immediately after the CT scan thatyour child needs I.V. or oral contrast. As a precaution, most children need to 'fast' (have nothing to eat or drink) before the CT scan.

    Arriving for the appointment

    CT is in the Medical Imaging (Radiology) department on the second floor of the Royal Children's Hospital. Enter from the main entrance on Flemington Road and follow the signs to the Medical Imaging department.

    • If your child's CT scan is to be performed under a general anaesthetic, you will need to go to the Day Centre. This is also on the second floor near the Medical Imaging Department. Your appointment letter will outline instructions on what to do and how to get there.
    • If your child needs to drink contrast before the test, they need to arrive one hour before the booking time.
    • If you already have been told they need a contrast injection, come at least 30 minutes before the booking time for the topical anaesthetic cream ('Angel cream') to go on your child's arm.

    After the scan

    If your child has not had I.V. contrast, you will be able to leave straight after the CT scan.

    If I.V. contrast was needed, we will observe your child for 10mins after the CT scan before allowing you to leave the department. If your child had a general anaesthetic (GA) you will need to wait until they are fully awake and until staff say it is OK to go home (see below).

    A radiologist will send the report to your referring doctor, usually within a week. If the results are needed earlier your doctor can phone the radiologist. 

    CT scan with general anaesthetic (GA) 

    Some CT scans at the RCH are done under general anaesthetic. This is usually for babies and younger children who cannot stay still or hold their breath for the duration of the scan. These children need to fast - have nothing to eat or drink - for six hours before the general anaesthetic.

    After the CT scan, your child will be taken to the recovery room where they are monitored until they are awake. Once awake, they can usually eat and drink right away, then go home about half to one hour later.

    For more information

    Developed by the RCH Day Surgery Unit.  First published Feb 2007. Updated October 2010

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