MRI Scanning Technique of Ankle Joint

Ankle joint can be scanned in a knee coil.

Initially localizer is taken.

T2 Sagittal sequence is taken in straight sagittal plane. The straight sagittal slices are set up off an axial scout image and are oriented parallel to the long axis of the foot. The epicenter of FOV is set at the middle of the ankle joint in sagittal localizer.

T2 Axial sequence is taken now. The straight axial slices should be roughly perpendicular to the long axis of the tibia and if the ankle is held in neutral position, will be roughly parallel to the bottom of the foot. The slices should begin well proximal to the level of the malleoli and extend distal to the calcaneus. The oblique axial slices are set up off the same straight sagittal reference image, and are oriented parallel to the long axis of the metatarsals. The slices should include all of the tarsals from the back of the calcaneus through the metatarsal bases. For forefoot, short axis (perpendicular to the long axis of the metatarsals) and long axis (parallel to the long axis of the metatarsals) plane are used for clinical scans.

 

T1 Axial sequence is planned by copying the slices of T2 Axial sequence.

T2 Coronal sequence is scanned then. The straight coronal slices, set up off a sagittal reference image should be oriented perpendicular to the plantar aponeurosis. Cover from proximal metatarsals to the distal calcaneus. The oblique coronal slices are oriented perpendicular to the posterior facet of the subtalar joint. The slices should include all of the hindfoot and midfoot.

Mortise Coronal slices are set up off a straight axial reference image taken through the top of the talar dome. The slices are aligned parallel to a line drawn between the medial and lateral malleoli. These slices are useful for imaging osteochondral lesions of talus and also for looking malleoli and the ankle ligaments.

Mortise Sagittal slices are set up off the same straight axial reference image and the slices are oriented perpendicular to the mortise coronal slices. These slices are useful for imaging osteochondral lesions of talus.

The routine sequence for MRI Scanning Technique of Ankle Joint are:

T2 Sagittal (Straight)

T2 Axial (Straight)

T2 Coronal 

T1 Axial

T2 Sagittal STIR (preferably Mortise Sagittal)

T2 Coronal STIR (preferably Mortise Coronal)

PD weighted sagittal images may be need to better delineate tears in the substance of the ankle tendons.

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