Severity analysis of neurovascular contact in patients with trigeminal neuralgia: assessment with the inner view of the 3D MR cisternogram and angiogram fusion imaging.

BACKGROUND AND PURPOSE Neurovascular contact (NVC) of the trigeminal nerve is not only detected at the affected trigeminal nerve in patients with trigeminal neuralgia (TN) but is also observed at the asymptomatic nerves on the side contralateral to the TN as well as in normal nerves in control subjects. The frequency and severity of the NVC among the affected, contralateral, and normal trigeminal nerves were analyzed by 3D MR cisternogram and angiogram fusion imaging in relation to the cause of TN. MATERIALS AND METHODS The inner view of the fusion MR imaging projected from inside the trigeminal nerve was used. The severity of the NVC was classified as none, simple, moderate, or severe, according to the nerve circumference in contact with the vessel. The NVC was analyzed in the affected nerves (n = 66) and the contralateral nerves (n = 66). Forty patients underwent microvascular decompression surgery, and 26 were treated medically. The NVC at the normal trigeminal nerves (n = 78) was studied in 39 control subjects without symptoms of TN. RESULTS The NVC in the affected trigeminal nerve was observed more frequently and much more severely than that at the contralateral and normal trigeminal nerves in controls (P < .01). Additionally, the NVC in the surgical patients was more severe than that in the medically treated patients (P < .01). CONCLUSIONS Severity analysis of the NVC with the inner view of the fusion MR imaging may provide useful information in the diagnosis of TN and can be a helpful adjunct in treatment planning for patients with TN.