Surface rendered three-dimensional MR imaging for the evaluation of trigeminal neuralgia and hemifacial spasm.

Surface rendered three-dimensional (SR3D) magnetic resonance (MR) imaging was used to visualize the cerebellopontine angle nerves, blood vessels and brain stem and compared with the operative view in patients undergoing microvascular decompression. Thirty-one patients with 32 affected nerves manifesting as trigeminal neuralgia (TN, 16 cases), hemifacial spasm (HFS, 14 cases) and glossopharyngeal neuralgia (2 cases) underwent microvascular decompression at the Kanto Neurosurgical Hospital between February 2001 and July 2002. Preoperative MR imaging and MR angiography were performed in all patients. The SR3D MR image and the operative view correlated in 30 of the 31 patients. A very thin artery was not detected in one patient with TN. SR3D MR imaging can clearly demonstrate the three-dimensional relationship between the nerves and the offending vessel, so is very effective for the preoperative planning of microvascular decompression in cases of TN and HFS.