Trigeminal Neuralgia: MR Sequence Selection and MRI Diagnosis

Objective To study MRI features and optimal sequences of trigeminal neuralgia, to evaluate MRI in the diagnosis of trigeminal neuralgia.Materials and Methods Using 3D constructive interference in steady state (3D CISS), 3D fast imaging with steady state precession (3D FISP) and 3D magnetization prepared rapid gradient echo imaging (3D MPR), combined with multi plane reconstruction, MR scanning was performed in 50 patients with trigeminal neuralgia and 25 normal subjects. Neurovascular compression or contact was observed.Results (1) Neurovascular compression or contact was found in 30% normal subjects and in 96% patients at symptomatic side. Vascular encapsulation and deformity of the nerve were found in 5 patients but none in normal subjects. (2) Of 50 patients, 38 showed neurovascular compression on or contact with the cisternal portion of the trigeminal nerve, of which 18 cases were proved by surgery. Ten patients were treated with γ knife. Seven patients had C P angle tumor, which was proved by surgery and pathology. On MRI, 5 patients showed vascular lesion, which was confirmed by microvascular decompression. (3) The difference in neurovascular compression or contact between normal subjects and patients was highly significant (P0.005). The diagnostic sensitivity and specificity of MR was 96% and 79%, respectively. Conclusion MR 3D CISS and 3D FISP, combined with 3D MPR sequences, have high sensitivity in judging neurovascular compression or contact. MRI plays an important role in demonstrating the relationship of the fifth cranial nerve with its surrounding vasculature, very useful in making preoperative evaluation and in guiding clinical management.