The most common cause of facial hemispasm is the contact of transitory (motor root exit) zone of the facial nerve and arterial vascular loop of PICA, AICA, vertebral or cochlear artery. Magnetic resonance imaging can rule out other serious causes and has a great impact on further treatment. 11 patients with hemifacial spasm were investigated on our apparatus Philips Gyroscan NT 15 (1.5 T) during 1. 9. 1995 and 25. 5. 1998. There were 2 men and 9 women from 20 to 89 years. Neurovascular conflict was demonstrated in all of them. The other possible etiology of hemifacial spasm is venous compression, tumour, aneurysm or AV malformation. We therefore consider magnetic resonance imaging indicated under these clinical circumstances.

        Key words: hemifacial spasm - computed tomography - magnetic resonance imaging - neurovascular conflict - Botulotoxin - microvascular decompression