발목 관절의 MRI 체크리스트
1. Tibiotalar joint including talar dome (T1W for subchondral signal change and T2W)
2. Subtalar joints : posterior, middle, anterior facets (T1 & T2)
3. Midfoot : calcaneocuboid joint, talonavicular joint, Lisfranc ligament
4. Interosseous membrane(high signal or thickening indicated injury : axial images)
5. Ligaments (at least axial and coronal proton density)
1) Lateral Ligament
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AITF : "D" shaped fibula on axial plane
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PITF : "D" shaped fibula on axial plane
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ATF : "C" shaped/concave fibula on axial plane
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PTF : "C" shaped/concave fibula on axial plane
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CF : normally not as black as anterior talofibular ligament
2) Medial Ligament (=Deltoid ligament)
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Deep Deltoid : normally heterogenous, if loses hetergeneity this is bad
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Spring ligament : travels under the talar head medial ankle
6. Tendons
1) Posterior Tendons
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Achilles tendon : normally concave or flat anteriorly on axials. Normally <6mm thick
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FHL can have fluid around it as well, FDL
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Tibialis posterior tendon
Allowed to have a small bit of fluid around it at the level of the medial malleolus, anymore and it is abnormal.
If the fluid is circumferential or if it is > 3mm thick then it is abnormal.
The normal tibialis posterior tendon should be only 2-3 times the size of the flexor digitorum tendon in the axial plane.
2) Anterior Tendons : Tibialis Anterior tendon, Extensor digitorum longus tendon
- Sinus tarsi : fat should remain preserve (FSE and T1 bright)
8. Plantar fascia
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Medial band is more commonly affected than lateral band
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If thickness of the medial band is >5 mm or if high T2 signal (edema) this is abnormal
9. Assess tarsal tunnel (look for masses such as ganglions or synovial cysts
10. Check the base of the 5th metatarsal for a fracture on the axial PDs
* Tendon anatomy
1. FHL = FDL X 2
2. TP = FDL X 2~3
3. PTT = FDL X 3~4
4. PB = FDL X 1.5