Fig 8. An intramedullary glioma extending from C2 to C4 displaying hyperintense signal intensity on T2-weighted images (A). The overlaid lines denote the levels corresponding to the axial sections in B–E. The lesion displays heterogeneous signal intensities on conventional T1 (B), EPI T2 (C), and diffusion–weighted (D) images as well as the FA map (E). Below the tumor (bottom row), a clear butterfly configuration attributed to the central gray matter of the cord is visible on T2 and diffusion-weighted images and FA map but not at the T1-weighted image. In fiber tracking, seeding of the entire superior and inferior cross-sections results in a veil of fibers around a region of low fractional anisotropy in the tumor into which tracks do not propagate, as seen when viewed in section (F, arrow). From external viewpoints, the thinning of the fiber volume is visible only when seeding is restricted to the white matter (G).