Figure 10e. Pilocytic astrocytoma of the optic nerve. (a) Coronal T1-weighted image shows enlargement (arrow) of the left optic nerve within the intraconal compartment. (b) Axial T1-weighted image reveals characteristic kinking (arrowhead) of the enlarged left optic nerve. (c) Axial proton-density-weighted image demonstrates mild hyperintensity of the mass. (d) Contrast-enhanced axial T1-weighted image shows intense enhancement of the mass. (e) Photograph of the resected optic nerve mass reveals a well-circumscribed sausagelike appearance.