What is assessed in a foot and ankle MRI?
A foot and ankle MRI allows assessment of the ligaments (lateral ankle ligaments, deltoid ligament, syndesmosis), the tendons (Achilles, tibialis posterior, peroneal, flexor and extensor tendons), the plantar fascia, the cartilage, the bones (talus, calcaneus, malleoli, metatarsals) and the soft tissues, including looking for a Morton's neuroma.
Because it uses a magnetic field rather than X-rays, MRI involves no ionising radiation and gives great detail of the soft tissues and of bone injuries that are not visible on a plain X-ray. The report is written by a radiologist; the clinical reading is your treating doctor's.
When it is requested
- Ankle sprain with persistent pain or a feeling of instability.
- Suspected Achilles tendon injury (tendinopathy or rupture).
- Tibialis posterior tendon dysfunction (adult acquired flatfoot).
- Plantar fasciitis that does not improve or where the diagnosis is unclear.
- Suspected stress fracture or a bone injury that does not show on an X-ray.
- Osteochondral injury of the talus (cartilage + bone).
- Morton's neuroma or other causes of forefoot pain.
- Assessment before or after surgery to the foot or ankle.
What the exam is like
- 1Before
Reception and safety questionnaire
Arrive 15 minutes early and fill in the safety questionnaire, if you haven't already done so online.
- 2
Changing room
You undress and stay in underwear with no metal parts; for a foot study, you may need to take off your shoes and socks. You are given a gown.
- 3
Positioning
The foot or ankle is placed inside a dedicated coil and you go into the scanner feet first.
- 4
Inside the scanner
Because you go in feet first, most of your body and your head stay outside the tunnel — one of the best tolerated MRI exams for people with claustrophobia.
- 520–30 min
Image acquisition
Several sequences with a characteristic noise; you are given ear protection. Contrast is rarely needed.
- 6
Finishing up
You get dressed and can leave without needing anyone to accompany you.
Preparation
- Fasting: not needed in general.
- Changing room and clothing: as a rule, you undress and stay in underwear with no metal parts. For a foot/ankle study, you may need to take off your shoes and socks; the radiographer will tell you what to keep on. You are given a gown.
- Devices and implants: note any pacemaker, neurostimulator and osteosynthesis hardware in the foot/ankle on the safety questionnaire.
- Documents: your referral, your insurer or subsystem card (if using an agreement), and any previous exams.
- Claustrophobia: you go in feet first and your head stays outside the tunnel — a well tolerated exam.
Results
The report is written by a radiologist from the images. The report is available as a PDF (by email or printed) and the images on CD and on CRMA's imaging platform, to take to your treating doctor — orthopaedic surgeon, physiatrist, family doctor or other.