[Dynamic nuclear magnetic resonance in strabismus]

To demonstrate that dynamic MRI is a useful tool in complex strabismus patients.

16 patients were referred to us with suspicion of slipped or '"lost" medial rectus (MR), 15 after strabismus surgery. 1 case with lost MR after trauma. One patient had "A" pattern exotropia with over depression in adduction. 8 underwent dynamic MRI examination.

The dynamic MRI showed the precise muscle location and the contractility of the muscle. All patients underwent surgery, according to deviation and ocular motility changes. All slipped muscles were found and re-attached to the globe. In the "A" pattern exotropia MRI showed superior displacement of the LR pulleys. The inferior rectus did not demonstrate contractility and a transfer procedure was made.

MRI is an index of functional muscle contractility and precise muscle location. It should be considered in complex cases of strabismus as an important argument in choosing the surgical technique.