HEMIFACIAL SPASM - 3-DIMENSIONAL MR-IMAGES IN THE EVALUATION OF NEUROVASCULAR COMPRESSION

PURPOSE: To assess the diagnostic accuracy of three-dimensional (3D) m agnetic resonance (MR) images in the preoperative evaluation of hemifa cial spasm. MATERIALS AND METHODS: In 27 patients with surgically conf irmed hemifacial spasm, the axial source images from 3D time-of-flight MR angiography were evaluated for 27 symptomatic sides and 26 asympto matic sides by three observers in a blinded manner for neurovascular c ompression and identification of compressive vessels. RESULTS: Sensiti vity was 95% and specificity was 77%. Vascular compression on the symp tomatic sides could be identified retrospectively in all 27 patients. On the asymptomatic sides, vascular compression could be excluded retr ospectively in all but one patient. In the blinded study, as the mean value of three observers, the vertebral artery and posterior inferior cerebellar artery could be identified correctly in seven and 7.7 of se ven and nine patients, respectively, whereas the compressive anterior inferior cerebellar artery was identified correctly in 7.7 of 16 patie nts. CONCLUSION: Three-dimensional MR images have a high diagnostic ac curacy and are useful in the preoperative evaluation of hemifacial spa sm.