Trigeminal neuralgia (tic douloureux): MR imaging assessment.

The magnetic resonance (MR) imaging studies and clinical records of 29 patients with typical or atypical trigeminal neuralgia (TN) were retrospectively reviewed and compared with the MR studies of 30 patients imaged for reasons unrelated to the fifth cranial nerve. The symptomatic patients were in three groups. Group 1 included those without masses or multiple sclerosis (MS) and those who had not undergone microvascular decompression; group 2, those who underwent microvascular decompression; and group 3, those with masses or MS. Twenty-seven percent of the control group and 57% of the symptomatic patients without masses or MS showed vessel contact with the root entry zone of the preganglionic segment of the fifth cranial nerve. Vessel contact in the symptomatic groups was generally indistinguishable from that seen in the normal group. Fifteen percent of the patients had MS or masses. It is concluded that MR imaging is useful in evaluating patients with TN by facilitating identification of MS or masses but is not helpful in selecting patients with vascular contact who might benefit from microvascular decompression.