196 High-Resolution Magnetic Resonance Imaging in Trigeminal Neuralgia: Added Benefit of Contrast Enhanced Constructive Interference in Steady State Imaging.

INTRODUCTION: MRI is performed in the assessment of patients with trigeminal neuralgia (TGN). However, there is poor contrast between vessels and nerves, because both are low in intensity on heavily T2-weighted images. METHODS: A retrospective review was performed of high-resolution 3D MRI studies of patients from 2011 to 2014. Eighty-one TGN patients and 15 controls were independently reviewed by 2 neuroradiologists in a blinded fashion. The cisternal segment of the trigeminal nerve root was assessed bilaterally for metrics of neurovascular conflict, including grade (0-3), nerve root cross-sectional area (CSA), and degree of flattening (DOF). The data were correlated with side of symptoms and postoperative pain relief after microvascular decompression (MVD). RESULTS: Grade 1 neurovascular conflict was prevalent on both the asymptomatic side (59.3%) and in controls (60%), but advanced grade neurovascular conflict was rare on the asymptomatic side (7.4%) and not seen in controls (0%). Grade 3 neurovascular conflict occurred in 46.9% on the symptomatic side, but was highly specific for that side (94.6%). Review of contrast-enhanced 3D constructive interference in steady state (CISS) imaging (CE-CISS) more than doubled the prevalence of grade 3 neurovascular conflict (14.8% vs 33.3%, P = .001), and yielded lower CSA and greater DOF for advanced grade neurovascular conflict on the side of symptoms compared with imaging without contrast (NE-CISS). Patients with complete pain relief after MVD had significantly lower CSA on CE-CISS compared with NE-CISS on preoperative imaging. The area under the curve (AUC) for predicting complete relief of symptoms after MVD was significantly higher for CE-CISS than for NE-CISS for grade of neurovascular conflict (AUC = 0.835 vs 0.803, P = .017) and CSA (AUC = 0.709 vs 0.682, P = .002). CONCLUSION: The addition of gadolinium-based contrast to 3D-CISS imaging improves performance in predicting the side of symptoms in patients with TGN and in predicting favorable outcomes after MVD, which may be helpful in preoperative planning.

Duke Scholars

Author Courtney Rory Goodwin Neurosurgery