MRI scan uses a magnetic field to create detailed two‑dimensional images of structures inside the body.
MRI stands for Magnetic Resonance Imaging.
MRI may be used:
to aid diagnosis and staging of retinoblastoma.
in routine follow up of high risk retinoblastoma.
in routine follow up of adults with constitutional RB1 mutation.
Before the Scan
Some children feel claustrophobic inside the scanner, so prepare your child for this. You can often arrange a pre-scan visit with your child to familiarise yourselves with the machine.
Some computer games are available that let your child hear how loud an MRI is when it is working, and prepare a character for their MRI.
Your child will be asked to remove jewellery and clothing containing metal, and may be asked to wear a hospital gown. You will be asked if she has any metal implants as these can interfere with the scanner. Orbital implants and artificial eyes contain no metal and are very safe for MRI.
Before or during the scan, your child may be given an intravenous injection of liquid contrast dye that creates clearer pictures of certain tissue types. If she does not have a central line, an IV will be inserted to deliver the contrast. The injection may make her feel hot or flushed for a minute. This does not hurt, but she may cry if she is unprepared for this sensation.
The contrast may make your child feel warm and tingly all over for a few minutes. This does not hurt, but she may cry if she is unprepared for the sensation.
The contrast often contains iodine. The technician will first ask if your child is allergic to it or has asthma. If the department knows about this in advance, the contrast can usually still be given, but your child will be given a steroid the day before and on the day of the scan, to prevent a reaction.
During the Scan
This painless scan takes 60 to 90 minutes. Your child will lie on the scanner bed, with her head on a special pillow. A device called a surface coil will be placed around her head to immobilize it and enable imaging.
The machine makes loud knocking noises as images are taken. Your child will be given earplugs or headphones to dull this sound. She will still be able to hear, and speak to, the technician through a microphone inside the scanner.
The scan bed will move so your child’s head is inside the cylindrical scanner. The technician will then leave the room during the scan.
Many hospitals allow parents to stay if the scan is done awake. You have the right to request this. Do advocate to stay with your child as your presence can be very reassuring.
Young children are often given a short acting general anaesthetic as it is vital they lay very still during the scan to obtain good images. However, with good child life support, children as young as 2 can complete the scan awake.
After the Scan
If your child completes the scan awake, you will be free to go as soon as it is over.
If she has sedation or a general anaesthetic, she will usually be taken to recovery or a day care ward. You will be allowed to leave once she is fully awake and has had something to drink.