Neurovascular Conflict on Asymptomatic Sides of Hemifacial Spasm Using Magnetic Resonance Imaging Three-Dimensional Volumetric Interpolated Breath-Hold Examination Sequence: A Retrospective Study.

Abstract

Neurovascular conflict (NVC) is commonly observed in patients with hemifacial spasm (HFS); in certain instances, NVC can also be identified on the asymptomatic side of patients with HFS through magnetic resonance imaging (MRI). It is vital to evaluate NVC in asymptomatic individuals and patients with HFS before performing microvascular decompression (MVD). The aim of this study was to evaluate the role of the MRI three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) sequence in distinguishing NVC in asymptomatic individuals and patients with HFS. We reviewed the magnetic resonance images of NVC on both the symptomatic and asymptomatic sides in patients with HFS undergoing MVD. All patients underwent MRI with 3D-VIBE sequence. The same neuroradiologist blindly described the differences of magnetic resonance images, including the location of NVC (root exit zone or cisternal segment of the facial nerve), severity of NVC (mild or severe), offending vessels, vertebral artery (VA) dominance, and VA tortuosity with 3D-VIBE in asymptomatic and symptomatic nerves. One hundred twelve patients who underwent MVD for HFS were enrolled in this study. In total, 104 patients with HFS met the inclusion criteria. Of these, the asymptomatic sides of 52 patients were included in the asymptomatic control group. Severe compression at the root exit zone and VA tortuosity were more commonly observed in symptomatic nerves than in contralateral asymptomatic nerves (P values < 0.05). We conclude that the 3D-VIBE sequence is a reliable noninvasive tool for evaluating NVC in asymptomatic individuals and patients with HFS. There were differences in the location, type of blood vessel, and severity of NVC in the 3D-VIBE sequence between asymptomatic individuals and patients with HFS. Knowledge of the MRI characteristics of frequent NVC in asymptomatic individuals is essential for evaluating and selecting the appropriate treatment.