Trigeminal neuralgia: evaluation of neuralgic manifestation and site of neurovascular compression with 3D CISS MR imaging and MR angiography.

PURPOSE: To evaluate three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging and MR angiography with multiplanar reconstruction (MPR) for detection of neurovascular compression (NVC) in patients with trigeminal neuralgia and to evaluate the relationship between clinical symptoms related to trigeminal branches and those related to the site of trigeminal nerve compression.
MATERIALS AND METHODS: Fifty-four consecutive patients with trigeminal neuralgia were examined at 3D CISS imaging and MR angiography with a 1.5-T MR system. Original transverse and four reformatted images were used for image interpretation. Vascular contact with the trigeminal nerve at the root entry zone (REZ) was determined, and the nature of the involved vessels was identified. The position of the blood vessel compressing the nerve was classified into cranial, caudal, medial, or lateral sites. Statistical analysis was performed with the chi2 test or the Fisher exact test between two groups and with the chi2 test among more than two groups.
RESULTS: In 12 of 15 patients who underwent surgery, the artery that was considered a responsible vessel at 3D CISS imaging and MR angiography was confirmed as such. In the other three patients, the vein was the responsible vessel, which was detected only at 3D CISS imaging. Sixteen (89%) of 18 patients with symptoms related to the maxillary division had NVC at the medial site of the REZ, while 16 (76%) of 21 patients with symptoms related to the mandibular division had NVC at the lateral site (P <.001, chi2 test).
CONCLUSION: 3D CISS MR imaging with MPR is useful in the detection of NVC in patients with trigeminal neuralgia, compared with MR angiography. A close relationship was found between the region of neuralgic manifestation and the site of trigeminal nerve compression. Copyright RSNA, 2003.