MRI though the optic apparatus of a child with NF1 demonstrates enlargement of both optic nerves. On the right, the nerve is enlarged just anterior to the chiasm but appears normal in the orbit whereas on the left the nerve is enlarged within the orbit. The abnormality extends back to the optic nerve canal but does not appear to reach the chiasm.
The enlarged left optic nerve is of high T2 signal and demonstrates contrast enhancement.
Features are consistent with bilateral optic nerve gliomas.