MRI of trigeminal neuralgia: initial clinical results in patients with vascular compression of the trigeminal nerve.

The most common cause of the idiopathic trigeminal neuralgia are tortuous arteries in the prepontine space. The trigeminal nerve can be compressed by the superior cerebellar artery, the inferior cerebellar artery, or the basilar artery. Seldom the nerve is traumatised by an enlarged vein. Because an operative decompression of the nerve can relieve pain, a preoperative evaluation is needed. Angiography of the vertebral arteries is able to predict a tortuous artery close to the trigeminal nerve but cannot show the nerve itself. MRI can show tortuous vessels and the trigeminal nerve together on one single image by means of a 3D gradient-echo FLASH sequence with an effective slice thickness of approximately 1 mm and secondary reconstructions in every desired plane. MRI thus provides an efficient tool for the evaluation of patients with trigeminal neuralgia.