Ankle Joint And Its Related Structures: A Comparative Study Between Cadaver Section And MR Imaging

Objective: The location, size, shape and adjacent relationships of ATFL, CFL, PTFL, ATTL, PTTL, CTL, NTL, AT, PTT, FDLT, FHLT, PBT and PLT on section specimens and MRI were studied to provide anatomic data for MRI diagnosis when foot was put in different positions. The optimal slices, sequences and methods of ankle and its related structures on MRI were investigated.Materials and methods: The location, size, shape and their adjacent relationships of ATFL, CFL, PTFL, ATTL, PTTL, CTL, NTL, AT, PTT, FDLT, FHLT, PBT and PLT on 40 ankle (natural position 34 cases, full plantar flexion 3 cases, full dorsiflexion 3 cases) section specimens were measured. SE, GE, STIR sequences of MR imagings were obtained on 40 normal ankle joints.Results: 1.The measurements on section specimens and their related values on MR imagings of ATFL, CFL, PTFL, ATTL, PTTL, CTL, NTL, AT, PTT, FDLT, FHLT, PBT and PLT were compared, but all have no significances.2. The lateral ligaments: ATFL and CFL show low-signal-intensity on Tl-weighted MR imaging. PTFL is composed of several strip shadow and show inhomogeneous signal intensity. With the foot taped into full dorsiflexion, axial images provided optimum views of ATFL through the slice end of lateral malleolus. Coronal images also provided optimum views of ATFL with the foot taped into full plantar flexion through the slice ahead of lateral malleolus. PTFL can show full-length views when foot was put into full dorsiflexion just above posterior subtalar joint. With the foot taped into full dorsiflexion, full plantar flexion and naturalposition, respectively coronal plane through back margin of lateral malleolus, axial plane and oblique axial plane through the sustentaculum tali of the calcaneus optimized visualization of CFL.3.The medial ligaments: ATTL, CTL, NTL and TSL show low-signal-intensity on Tl-weighted MR imaging. PTTL is the largest ligament of the medial ligament and show inhomogeneous signal intensity within some high signal intensity of fat. The coronal plane with the foot taped into full plantar flexion and the oblique coronal plane with the foot taped into natural position ahead of medial malleolus, can show ATTL clearly. The axial plane with the foot taped into full dorsiflexion through talotibilal joint, can also show ATTL clearly. The coronal plane in the middle of medial malleolus and the axial plane end of medial malleolus with the foot taped into full dorsiflexion, provided an overview of PTTL. The coronal plane with the foot taped into full plantar flexion and the oblique coronal plane with the foot taped into natural position, ahead of medial malleolus can show NTL well. With the foot taped into full dorsiflexion through the trochlea of talus, axial plane provided optimum views of NTL. With the foot taped into full dorsiflexion through medial malleolus and the below planes, the coronal plane and axial plane provided the best full-length views of CTL and TSL.4.Tendons: AT, the medial tendons and lateral tendons show low-signal-intensity on Tl-weighted MR imaging. Sagittal and coronal planes can show AT well and full-length views can be provided in these planes. The axial is the best plane that can be used to demonstrate PTT, FDLT and FFELT. The oblique coronal plane can show PBT and PLT well.5. We found T1WI SE sequences can show normal ligaments and tendons clearly on MR imagings, GE-STIR can show the diseases of ligaments and tendons well.Conclusion: MRI can show the anatomic structures of ATFL, CFL, PTFL,ATTL, PTTL, CTL, NTL, AT, PTT, FDLT, FHLT, PBT and PLT of the ankle in detail. There are no significant differences between the data of MRI and that of cadaver sections. Different foot positions, different imaging planes and imaging sequences can demonstrate the ankle joint and its related structures in various degrees.