Non-invasive Assessment of Microstructural Changes After CyberKnife Radiosurgery for Trigeminal Neuralgia Using Diffusion Tensor Imaging

Abstract

Background and Aims: Given the absence of a universally accepted non-invasive and objective clinical tool to predict a patient’s response to stereotactic radiosurgery for Trigeminal Neuralgia (TN), this research endeavoured to appraise the potential of Diffusion Tensor Imaging as a predictive tool in managing TN. Objective: This study aimed to assess microstructural changes in the trigeminal nerve following CyberKnife radiosurgery (CKRS) for TN using diffusion tensor imaging (DTI) and to correlate these changes with clinical outcomes. Methods: Twenty-eight TN patients treated with CKRS underwent pre and 4-month post-treatment Three-Tesla magnetic resonance imaging scans with DTI metrics, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were collected. Clinical outcomes were assessed using the Barrow Neurological Institute Pain Intensity Score (BNI-PIS) at fourth, sixth and ninth months post-CKRS. Results: Twenty-four patients reported good pain relief (responders), while four patients did not experience adequate relief (non-responders). Responders exhibited significantly lower FA (mean drop of 13.8%, P < .001) and lower RA (mean drop of 16.1%, P < .001) compared to non-responders. RD, AD and MD remained constant across the study cohort. Conclusion: DTI metrics, particularly FA and RA, at 4 months post-CKRS, emerged as predictors of long-term treatment effectiveness for TN. These findings suggest the potential utility of DTI in evaluating microstructural changes in the trigeminal nerve post-CKRS and predicting clinical outcomes.