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

Abstract

Optic pathway glioma (OPG) is a characteristic hallmark of neurofibromatosis type I (NF-I). 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. 3-T MRDTI was prospectively performed in 9 children with NF-I (7 boys, 2 girls, average age 7.8years, range 3-17years) and 44 controls (25 boys, 19 girls, average age 8.1years, range 3-17years). 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. 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. 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.