Vascular compressive abducens nerve palsy disclosed by magnetic resonance imaging

PURPOSE: To assess magnetic resonance imaging as a diagnostic tool of neurovascular compression in a patient with abducens nerve palsy. METHODS: We performed magnetic resonance imaging of the brainstem of a 46-year-old patient with left abducens nerve palsy using spoiled gradient recalled acquisition in the steady state (SPGR), which allows high-resolution T-1-weighted imaging and detection of the arteries across the plane of slices as a high-signal-intensity area. RESULTS: Computed tomography of the brain was unremarkable except for leftward shifting of the basilar artery, As disclosed by magnetic resonance imaging with the SPGR, the right vertebral artery was shifted to the left and joined with the left vertebral artery, and the left abducens nerve was compressed by the vertebral artery. No other abnormal signals were seen in the brainstem. CONCLUSIONS: These findings suggest that the abducens nerve palsy in this patient was caused by vascular compression at the root exit zone. Magnetic resonance imaging with the SPGR is useful for the diagnosis of vascular compressive neuropathy.