20. Magnetic resonance volumetry confirms trigeminal nerve atrophy in patients suffering from essential trigeminal neuralgia

Abstract

Objective The aim of this study was to assess trigeminal nerve (TN) atrophy in trigeminal neuralgia (TNr) using magnetic resonance imaging (MRI) in patients that subsequently underwent gamma knife surgery (GKS) and to evaluate correlation between anatomic findings and clinical data. Methods We measured TN volumes along their course through the pontocerebellar cistern in 55 subjects. MRI was performed on a 1.5 T Siemens Avanto scanner using a CISS sequence (T2 ci3d, slice thickness 0.9 mm, inplane resolution 0.45 × 0.45 mm, TE 2.47 ms, TR 5.54 ms, NEX = 2). Volumometry was performed in a consistent grayscale using an auto-level mode in Leksell GammaPlan v.10.1 by manually tracing the contours. Two independent investigators carried out the measurements. Statistical analyses (paired Wilcoxon test, descriptive statistics and Spearman non-parametric correlation) was calculated in GraphPad Prism 5.01. Results The volume of the TN on the affected side was significantly smaller (32.6 ± 13 (SD) – observer DU and 31.6 ± 12 mm 3 – observer VS) than the volume of the unaffected side (41.2 ± 18 mm 3 , and 36.53 ± 14; p mm 3 (observer VS)) were detected. Conclusion TN volumes significantly differ among affected and unaffected TN in TNr patients. Statistically significant correlation between the duration of pain and TN volume was not found and atrophy was not observed to progress throughout the course of the disease, suggesting that volume changes may be a predisposing factor for TNr. This study was supported by IGA MZ CR NT11328 and Research Project Charles University in Prague PRVOUK P34.