Three-dimensional-MRI of neurovascular compression in patients with hemifacial spasm.

We prospectively studied 30 patients to assess the usefulness of three-dimensional (3D) contrast-enhanced MRI in patients with hemifacial spasm. In all patients neurovascular compression of the facial nerve could be detected. Microvascular decompression was performed in 14, and vascular compression of the root exit zone of the facial nerve and the offending artery were exactly as predicted by MRI in all but 2. We also retrospectively studied whether the symptomatic side could be defined only by enhanced 3D MRI in 55 randomised individuals (30 with and 25 without hemifacial spasm). All symptomatic sides were correctly identified, and the false-positive rate was 13.8%.