Getting ready for a scan
MRI, CT, ultrasound and X-ray: what each one is for, how to prepare and what it feels like.
Your doctor chooses a scan according to what they need to see. Whichever one you’re having, bring your request form, your ID and health card, and any earlier scans of the same area.
MRI
MRI uses a strong magnet and radio waves, with no radiation. It’s the best test for the brain, spine, joints and soft tissue. You lie still inside a tunnel for 20 to 60 minutes, and the machine is loud, so you’ll be given ear protection.
- Tell the team beforehand if you have a pacemaker, a cochlear implant, aneurysm clips, a joint replacement, metal fragments from an injury, or if you might be pregnant.
- Leave jewellery, watches, bank cards and hairpins outside the room.
- If small spaces make you anxious, tell your doctor in advance. There are ways to help.
CT
CT takes X-ray pictures from many angles to build a detailed image. It takes only a few minutes. For some scans you’ll be given contrast dye to drink or through a vein, which can cause a warm feeling for a few seconds.
- Tell the team if you have kidney problems, diabetes treated with metformin, a previous reaction to contrast dye, or if you might be pregnant.
- You may be asked not to eat for a few hours beforehand.
Ultrasound
Ultrasound uses sound waves, with no radiation, and is safe in pregnancy. A probe is moved over the skin with a little gel.
- For a scan of the abdomen, you’ll usually be asked not to eat for six to eight hours.
- For a pelvic or early pregnancy scan, you’ll usually need a full bladder.
X-ray
An X-ray is the quickest test of all and the usual first look at bones and the chest. Tell the radiographer if you are or might be pregnant.
Your results
A radiologist studies the images and sends a written report to the doctor who requested the scan. Ask when you book how and when you’ll receive yours.