Optic nerve tortuosity in children with neurofibromatosis type 1

Abstract

Optic nerve tortuosity is often reported in children with neurofibromatosis type 1 (NF1). To employ quantitative and subjective criteria to assess optic nerve tortuosity in individuals with NF1. A retrospective study over a period of 8years was performed on children with NF1, with and without optic pathway glioma, compared with children without NF1. A tortuosity index was computed for the optic nerve in each child using a high-resolution 3-D T1-weighted magnetization-prepared rapid gradient-echo sequence, which was averaged and compared across groups. The tortuosity index for subjects with NF1, regardless of an optic pathway glioma, was greater than those without NF1. There was no difference in the tortuosity index between NF1 subjects with optic pathway glioma and NF1 subjects without optic pathway glioma. There was also no correlation between subjective measures of tortuosity and the quantitative scoring (tortuosity index) or between the degree of tortuosity and subject age or gender. Individuals with NF1 have increased optic nerve tortuosity relative to unaffected individuals. Quantitative tortuosity index is a superior measure to subjective assessment in the evaluation of optic nerve tortuosity in children with NF1.