Magnetic resonance diffusion tensor imaging (MRDTI) of the optic nerve and optic radiations at 3T in children with neurofibromatosis type I (NF-1)

Background Optic pathway glioma (OPG) is a characteristic hallmark of neurofibromatosis type I (NF-I). Objective To evaluate the feasibility of magnetic resonance diffusion tensor imaging (MRDTI) at 3T to detect abnormalities of the optic nerves and optic radiations in children with NF-I. Materials and methods 3-T MRDTI was prospectively performed in 9 children with NF-I (7 boys, 2 girls, average age 7.8 years, range 3–17 years) and 44 controls (25 boys, 19 girls, average age 8.1 years, range 3–17 years). Fractional anisotropy (FA) and mean diffusivity were determined by region-of-interest analysis for the optic nerves and radiations. Statistical analysis compared controls to NF-I patients. Results Two NF-I patients had bilateral optic nerve gliomas, three had chiasmatic gliomas and four had unidentified neurofibromatosis objects (UNOs) along the optic nerve pathways. All NF-I patients had statistically significant decreases in FA and elevations in mean diffusivity in the optic nerves and radiations compared to age-matched controls. Conclusion MRDTI can evaluate the optic pathways in children with NF-I. Statistically significant abnormalities were detected in the diffusion tensor metrics of the optic nerves and radiations in children with NF-I compared to age-matched controls.