Objective: Brown syndrome is characterized by limitation of elevation in adduction, with complex mechanisms involving muscle, tendon, and trochlea. Here, we investigated mechanisms of Brown syndrome by magnetic resonance (MR) imaging.
Methods: It was a retrospective case series study. Fourteen patients with unilateral Brown syndrome between 3 and 54 years of age (10 cases of congenital and 4 cases with acquired disease) were included in the study. All patients underwent complete ophthalmic and orthoptic evaluation. Imaging of the ocular motor nerves at the brainstem was performed on 3D-FIESTA sequence, the orbits were imaged with FSE T1, T2WI using surface coils.
Results: Nine of 10 with congenital Brown syndrome demonstrated hypoplasia of the superior oblique (SO) of the affected side. Abnormal low signal intensity in the trochlea area was found in one patient. Three of 4 acquired patients had a history of trauma and were demonstrated fracture of the trochlea, extensive scarring, and superior orbital fracture. One acquired case was demonstrated scarring of anterior part of the SO and hypoplasia of the posterior part.
Conclusion: Brown syndrome consists of a series of diseases. Their clinical features are quite similar while their anatomical mechanism varies in numerous ways. Therefore, based on patient's individual pathophysiology, the management in Brown syndrome should be personalized.