Evaluation of Optical Radiation from Visual Pathways with Diffusion Tensor Imaging in Patients with Neurofibromatosis Type 1

Abstract

Objective:It was investigated whether patients with neurofibromatosis type 1 (NF1) with and without optic glioma (OG) differed from the healthy control group in terms of diffusion tensor imaging (DTI) parameters obtained from optic radiation.Methods:Eighty three patients and 36 healthy controls followed with the diagnosis of NF1 were included in the study. Routine MRI and DTI were applied to all subjects. Fractional anisotropy (FA), mean diffusity (MD), radial diffusity (RD) and axial diffusity (AD) values were calculated by placing ROI on the right and left optic radiation on colored FA maps. Patients with OG detected by conventional magnetic resonance imaging (n=19) were classified as group 1, patients with NF1 without OG (n=64) were classified as group 2 and they were compared with the healthy control group in terms of DTI parameters.Results:The right and left optic radiation FA values of the patients in group 1 and group 2 were significantly different when compared with the healthy control group. Optical radiation FA values were significantly lower than healthy control group. MD values in group 1 patients with OG were significantly higher than healthy control group. Optic radiation RD values were significantly higher in group 1 and group 2 compared with healthy control group.Conclusion:There appears to be microstructural damage in optic radiation in patients with NF1 with or without OG. The idea that changes in FA values detected in optic radiation in visual pathways in patients with NF1 can be predicted in the early period of visual impairment is promising in terms of treatment planning and management.

Keywords

• neurofibromatosis type 1
• optic gliom
• diffusion tensor imaging
• fractional anisotropy