Diagnosis of vascular compression in facial spasm by stereoscopic short-range magnetic resonance angiography. Technical note.

The authors describe the use of stereoscopic short-range magnetic resonance (MR) angiography to diagnose whether and by what means the brainstem is compressed in a case of facial spasm. The MR images were obtained on a 1.5-tesla imaging system with three-dimensional time-of-flight pulse sequence (repetition time 39 msec, echo time 9 msec). Six-source MR images, in which the internal acoustic meatuses were described, were processed using a maximum-intensity projection technique to reconstruct the MR angiograms. The internal acoustic meatuses, the posterior fossa, and the nearby arteries are shown on a single MR angiogram. When two MR angiograms with projection angles 10 degrees apart are placed side by side and observed through polarized glasses, a stereoscopic view of the compressing artery can easily be seen.