Usefulness of high-resolution magnetic resonance cisternography in patients with hemifacial spasm.

To analyse the usefulness of preoperative magnetic resonance (MR) cisternography in patients with hemifacial spasm (HFS), MR observations were compared with surgical findings. High-definition images were obtained using MR cisternography which employed a long echo train length, fast spin-echo sequence, which revealed both nerves and blood vessels without any contrast media. In 35 HFS patients, certified radiologists examined the presence of vascular compression of the facial nerve and identified the offending vessels. MR cisternography depicted neurovascular compression in 31 patients (sensitivity 88.6%) and correctly determined the offending vessels in 28 patients. In 4 patients, MR cisternography revealed the presence of the vessel near the facial nerve, but the radiologist evaluated the compression as questionable (false-negative rate 11.4%). Even in these patients, MR cisternography revealed the precise anatomy of cerebellopontine (CP) cistern. High-resolution MR cisternography is useful in identifying the vessels and nerve bundles in the CP cistern, and in so doing can provide surgeons with valuable information regarding neurovascular decompression for HFS.