This page explains about what happens when your child has an MRI scan without sedation or general anaesthetic and what to expect when your child comes to Great Ormond Street Hospital (GOSH) to have this procedure.
An MRI (magnetic resonance imaging) scan uses a magnetic field rather than X-rays to take pictures of your child’s body. The MRI scanner is a hollow machine with a tube running horizontally through its middle. Your child will lie on a bed that slides into the tube. An MRI scan usually lasts between 20 minutes and an hour.
Watch our short video film about having an MRI or listen to our audio podcast. If you would like further advice about preparing your child for the scan, please ring the department’s play specialist on the numbers below.
Are there any alternatives?
Your child may need this scan so that their doctors can get detailed pictures of the size and shape of part of your child’s body. Various types of scan such as CT, ultrasound and X-rays can show the size and shape of parts of your child’s body, but not in as much detail as an MRI scan. The information from the scan is then used to help with diagnosis and plan their treatment.
When you receive your appointment letter
If you are unable to keep this appointment, please inform the department as soon as possible beforehand. Sometimes, we can offer the appointment to another child on the waiting list.
The day of the scan
When you arrive at the hospital, you should report to the MRI department. Some scans need additional preparation – information about whether your child needs any additional preparation is in your appointment letter. Your appointment time is 30 minutes before the scan is scheduled. We need this time to prepare you and your child, for instance, completing the metal check described below and to apply some local anaesthetic cream in case your child needs an injection.
Children having the scan without sedation or general anaesthetic do not need to fast or stop eating and drinking before the scan, unless stated in the appointment letter.
Your child should wear clothes without zips or metal poppers for the scan – otherwise they will need to change into a gown. Before the scan starts, the nurse or radiographer will check you or your child do not have a pacemaker, metal implants or clips, dental braces, a history of metal fragments in the eyes or any allergies. We will ask you to sign a form to confirm this. If you are wearing a medication patch, for instance, for pain relief or to quit smoking, please remove this before you go into the scanner room. You will also need to leave metallic objects like jewellery, watches, keys, pens or cards with metallic strips like bank cards and train tickets in the lockers outside the scanner room.
You are welcome to stay with your child during the scan, but if you are in the first three months of pregnancy, you should let us know beforehand. If your daughter is 12 years old or older, we will ask her about her periods and any possibility she could be pregnant.
Your child will be able to watch a DVD during the scan, so please bring along any favourites. It can also help if your child has a favourite toy to hold as well.
What does the scan involve?
Your child will need to lie on the bed for the scan. Depending on the part of their body being scanned, they may need to have a coil over part of their body or wear a head coil (this will not touch their head).
When your child is in the correct position, the radiographer will move the bed inside the scanner and then go into the control room. The scanner will make a continuous knocking sound throughout the scan, which can be quite loud, but we will give you and your child ear protectors to minimise any discomfort. If your child is watching a DVD, or listening to a CD, this will distract from the noise too.
The radiographer will warn you and your child when a loud noise is due by talking to them through an intercom. When the scan has finished, the radiographer will move the bed out of the scanner and your child can get up and leave.
Medicines given during an MRI scan
We may give your child some medicine during the MRI scan to make the image clearer. The radiographer will tell you which medicines your child has had in case of later side effects. The medicines we use most often at Great Ormond Street Hospital (GOSH) include:
Secretin – This is a naturally occurring hormone that increases the volume of juice within the duct of the pancreas. It is given as an injection. Possible side effects include: loose or runny poo, cramplike stomach ache, headache, skin itching and a rash.
Hyoscine butylbromide (Buscopan®) – This medicine relaxes the smooth muscle of the intestine. Possible side effects immediately after the injection include: dilated pupils, dry mouth, flushing of the skin, dislike of bright light and palpitations. In the hours following the injection, other side effects may occur: constipation, urinary retention and urinary urgency.
Furosemide – This medicine increases the production of urine immediately after injection. Possible side effects include: low blood pressure and dehydration. You can reduce these side effects by encouraging your child to drink plenty of fluids in the hours after the scan.
Mannitol – This medicine is drunk and allows clear imaging of the wall of the bowel. A common side effect is loose or runny poo, so in the first few hours after the scan, your child should have access to a toilet. Dehydration may also occur, so ensure plenty of fluids in the hours following the scan.
Gadoteric acid (Dotarem®) – This is a dye that makes blood vessels and any inflammation show up more clearly on the pictures. It is given as an injection. A possible side effect is hypersensitivity, but this will normally be an immediate effect. There are no reported long term side effects of gadoteric acid.
Are there any risks?
There are no risks associated with MRI scans. They are painless with no lasting effects. The scanner does not touch your child during the scan. MRI scans are not suitable for people with certain metal implants inside them (such as pacemakers) because the scanner emits a strong magnetic field. This is why we carry out a thorough metal check before your child has the scan.
What happens afterwards?
In most cases, your child will be able to go home straight after the scan has finished. The radiologist (doctor specialising in scans) will send a report of the scan to your child’s doctor in time for their next appointment. If you have not been given a follow up appointment to see your consultant, please contact their secretary after two weeks.
Last reviewed by Great Ormond Street Hospital: January 2013
Please note this is a generic GOSH information sheet. If you have specific questions about how this relates to your child, please ask your doctor. Please note this information may not necessarily reflect treatment at other hospitals.