About an ankle MRI scan
The ankle is a complex joint where the shin bones (tibia and fibula) meet the talus bone of the foot. It is held together by strong ligaments and surrounded by tendons, including the Achilles tendon at the back, the peroneal tendons on the outside and the tibialis posterior tendon on the inside. Ankle sprains are among the most common sports injuries.
An MRI scan uses a strong magnetic field and radio waves, not X-rays, to make detailed pictures of the ankle. X-rays mainly show bone, whereas MRI also shows soft tissues such as ligaments, tendons and cartilage, as well as bruising inside the bone that cannot be seen on an X-ray. This makes it useful when ankle pain, swelling or instability has not settled, or when a more serious injury is suspected. Left and right ankles are separate scans, so choose the side you need when you book.
What happens during the scan
You lie on your back on the scanner bed with your foot and ankle in a special coil. Usually only your legs and lower body go into the scanner, so many people find this scan easier than a scan of the head or body. The scanner is loud, so you will wear ear plugs or headphones, and you need to keep your foot still while the pictures are taken. Contrast dye is not usually needed.
What the scan can show
An ankle MRI can help to look at:
- ligament sprains and tears, including the outer ankle ligaments and “high ankle sprains” of the ligaments joining the shin bones
- damage to the cartilage and bone surface of the talus (osteochondral lesions)
- tendon problems, including Achilles, peroneal and tibialis posterior tendon tears and tendinopathy
- bone bruises and stress fractures that may not show on an X-ray
- impingement, where tissues are pinched as the ankle moves
- nerve compression on the inner ankle (tarsal tunnel syndrome) and lumps such as ganglion cysts
- arthritis and joint inflammation
A normal MRI does not always rule out every ligament or cartilage injury, so your doctor will consider the scan alongside your symptoms and examination.
Preparing for your scan
No special preparation is needed for an ankle MRI. You can eat and drink normally. If you have been given a walking boot, splint or cast, bring it with you; the radiographer will tell you whether it needs to come off for the scan.
You can usually eat, drink and take your normal medicines unless the scanning centre tells you otherwise. Wear loose, comfortable clothing without metal zips or buttons, and leave jewellery at home. You will be asked to remove metal items such as hair clips, hearing aids, coins and keys, and you may be asked to change into a gown.
Before the scan you will complete a safety questionnaire. Tell the team if you have a pacemaker, any metal implant, surgical clips or other device, if you have kidney problems or allergies, or if you are, or might be, pregnant or breastfeeding. If you feel anxious in enclosed spaces, let us know when you book. Some centres can offer a relaxant, and if you take one you will need someone to take you home and must not drive for 24 hours.
Frequently asked questions
Should I have an X-ray or an MRI for my ankle?
An X-ray is usually the first test after an injury to check for a broken bone. An MRI is used when pain, swelling or instability continues, or when an injury to the ligaments, tendons or cartilage is suspected, as these do not show on an X-ray.
Will my whole body go into the scanner?
Usually not. For an ankle scan you normally go into the scanner feet first, and your head stays outside or near the opening.
Do I need to book the left or right side?
Yes. Each ankle is a separate scan. If you need both, book them together, as two or more areas booked together qualify for the lower clubbed price.
Do I need a referral?
You can tell us if you have a referral from your GP, physiotherapist or consultant and upload it when you book. If you do not have one, select “no referral” when you book and the scanning centre will confirm the next steps with you.
Sources
- Gorbachova T. – Magnetic resonance imaging of the ankle and foot (Polish Journal of Radiology, 2020)
- RadiologyInfo.org – Musculoskeletal MRI
- NHS – MRI scan
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.