DIAGNOSIS OF VASCULAR COMPRESSION IN FACIAL SPASM BY STEREOSCOPIC SHORT-RANGE MAGNETIC-RESONANCE ANGIOGRAPHY

The authors describe the use of stereoscopic short-range magnetic reso nance (MR) angiography to diagnose whether and by what means the brain stem is compressed in a case of facial spasm. The MR images were obtai ned on a 1.5-tesla imaging system with three-dimensional time-of-fligh t pulse sequence (repetition time 39 msec, echo time 9 msec). Six-sour ce MR images, in which the internal acoustic meatuses were described, were processed using a maximum-intensity projection technique to recon struct the MR angiograms. The internal acoustic meatuses, the posterio r fossa, and the nearby arteries are shown on a single MR angiogram. W hen two MR angiograms with projection angles 10 degrees apart are plac ed side by side and observed through polarized glasses, a stereoscopic view of the compressing artery can easily be seen.