The Diffusion Tensor Imaging Features in the Visual Pathways of Patients with Cavernous Sinus Meningioma Treated by Gamma Knife Radiosurgery

Objective: The objectives of this study are to evaluate the effects of diffusion tensor imaging (DTI) on visual pathways following Gamma Knife radiosurgery (GKR) and to identify any correlations between DTI results and radiosurgery data. Methods: Thirteen patients with cavernous sinus meningiomas (CSMs) and 15 controls were included. Mean diffusion coefficient (ADC), fractional anisotropy (FA), and radial diffusivity (RD) were assessed in the visual pathways using DTI, and DTI values were compared between healthy subjects and patients before and after 12 months of GCR imaging. Additionally, the correlation between these values and radiosurgery data was also investigated. Results: The ADC, FA, and RD values measured at visual pathways prior to and following GKR did not differ statistically. The FA values obtained from optic chiasm and occipital lobe were negatively correlated with the maximum and mean radiation dose to the prechiasmatic optic nerve and optic apparatus, respectively. The maximum radiation dose to the optic apparatus and the RD values obtained from the optic chiasm were found to be positively correlated. The maximum and mean radiation doses to the optic apparatus were found to positively correlate with the ADC and RD values obtained from the occipital lobe. Conclusion: Defining the radiation-related microstructural diffusion changes in visual pathways following GKR may provide useful information for tailoring the radiosurgical approach and safety of the treatment. Diffusion tensor imaging may provide useful information to characterize changes of the radiation effects on visual pathways in patients with CSMs after GKR.