The standard ankle MR protocol covers from the tarsometatarsal joints to the Achilles tendon and is an excellent general purpose tool for ankle pain. It is the gold standard method to assess
- Cartilage and articular surfaces
- Ligaments (including distal tibiofibular syndesmosis)
- All tendon groups
- Plantar fascia
- Bone marrow (i.e. stress repsonses / fractures)
With simple adaptations the same series can be used to assess and characterise bone lesions.
AT ALL COSTS the Fankle scan including the whole forefoot, midfoot and ankle in a single sequence should be avoided
Positioning
Ankle at 90deg neutral position, patient lying supine. Ankle of interest placed at scanner isocentre.
Scan
- High resolution ankle coil
- Base FOV 140mm ± 1mm
- Simple orthogonal planes used unless otherwise indicated
| Sequence | TE / TR | Slice / Gap / Matrix | Other |
|---|---|---|---|
| PDFS Axial | 37 / 2000 | 3mm / 0.5mm / 448 x 640 | Weak FS, Avg1 GRAPPA 2, Interpolate |
| PD Axial | 33 / 3330 | 3mm / 0.5mm / 448 x 640 | as above |
| PD Sagittal | 33 / 2000 | 3mm / 0.4mm / 512 x 640 | as above |
| PDFS Sagittal Oblique | 32 / 3300 | 3mm / 0.5mm / 512 x 640 | as above |
| PDFS Coronal | 30 / 2000 | 3mm / 0.5mm / 448x640 | as above |
| PD Coronal | 43 / 2000 | 3mm / 0.5mm / 448x640 | as above |
Variants
Suspected infection or bone tumour
| Sequence |
|---|
| T2FS Axial |
| T1 Axial |
| T1 Sagittal Oblique |
| STIR Sagittal Oblique |
| STIR Coronal |
Coping with metal work
- Increase slice gap to 20%
- Use higher bandwidth STIR or PDFS sequences
- Use MARS algorithms (such as SEMAC)