MRI Ankle and Hindfoot — routine
Distal tibia and fibula through the talus, calcaneus and midfoot. Extend to the forefoot where diabetic foot infection is the question.
Typical, not policy
Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.
When to use it
- Suspected Achilles, peroneal or tibialis posterior tendon tear or tendinopathy.
- Osteochondral lesion of the talar dome.
- Chronic ankle instability with suspected ligament injury.
- Plantar fasciitis or hindfoot pain not responding to treatment.
- Suspected osteomyelitis in the diabetic foot, where marrow signal and soft-tissue collections both matter.
Technique
- Axial, coronal and sagittal imaging with both a fluid-sensitive fat-suppressed sequence and a T1 or proton-density sequence in each relevant plane.
- Axial plane perpendicular to the long axis of the tibia for tendons; the peroneal and posterior tibial tendons are best assessed in true axial sections.
- Small field of view and thin slices; the structures of interest are only a few millimetres across.
- For suspected osteomyelitis, T1 is the key sequence — confluent low marrow signal is the discriminator — with post-contrast imaging to define abscess and sinus tracks.
Where it goes wrong
- Magic-angle artefact in curving tendons, especially the peronei around the lateral malleolus, mimicking a tear on short-echo sequences.
- Positioning in plantar flexion, which exaggerates magic-angle effects and distorts tendon course.
- Field of view limited to the ankle when the diabetic foot question requires the forefoot.
- Relying on fluid-sensitive sequences alone for osteomyelitis, where reactive oedema overcalls marrow involvement without the T1 correlate.
Clinical questions that reach this study
Contrast
NoneGadolinium, intravenous
Where infection or tumour is suspected, a macrocyclic gadolinium agent at a typical single dose of about 0.1 mmol/kg with fat-suppressed post-contrast T1.
- Routine tendon, ligament and osteochondral assessment is unenhanced. Contrast is added for suspected osteomyelitis, abscess and soft-tissue mass.
Acquisition
- Breathing
- Not applicable; foot immobilised in a dedicated coil in neutral dorsiflexion where tolerated.
- Preparation
- Say which structure is suspected: the coil, centring and plane angulation differ between an Achilles question, a hindfoot question and a forefoot question. For suspected diabetic foot infection, the field of view must be extended to include the forefoot and contrast is usually added.
Safety checks this protocol carries
Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.
- MR safety screening for implants and foreign bodies· radiographer at scan