Magnetic resonance imaging and angiography in hemifacial spasm.

We used magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) to investigate 14 patients with unilateral hemifacial spasm (HS) and 20 controls. The relationship of the seventh and eighth cranial nerves to adjacent vessels was best visualized on the contiguous flow sensitive 3D-FISP images. Reconstruction of projectional MRA was helpful to assess the complex architecture of the vertebrobasilar system. Neurovascular contact in the facial nerve root exit zone was present in 4 of 20 controls and in 12 of 14 patients, in whom it predicted the affected side. These results support previous findings of surgical and electrophysiological investigations that local irritation of the facial nerve is the most possible explanation for HS. MRI and MRA provide vascular and brain tissue diagnosis in a single non-invasive examination and should be recommended as primary neuroradiological procedure in HS.