[Magnetic resonance imaging of idiopathic trigeminal neuralgia].

Seventeen patients with idiopathic trigeminal neuralgia (ITN) and seven subjects of control group were evaluated with magnetic resonance imaging (MRI). Vascular contact at the proximal portion of the preganglionic segment (PGS) of the trigeminal nerve was observed in 100% of ITN on the affected side, 76% of ITN on the non-affected side, and 21% of control group. Deformity of the PGS was observed in 65% of ITN on the affected side, and in none of ITN on the non-affected side or control group. Non-surgical treatments were effective in all of the 6 patients without deformed PGS, but they failed to control trigeminal neuralgia in 4 of 11 patients with deformed PGS. This preliminary study suggests that MRI could be used for the clinical assessment of trigeminal neuralgia before treatment.