FIG 4. Axial gradient-echo 8-T MR images (600/12, 23° flip angle, 2-mm section thickness, 1024 x 1024 matrix, 20-cm FOV) display the medullary veins in the head of a healthy volunteer. The image is centered at the centrum semiovale and shows many transmedullary veins (black arrowheads) that drain into the subependymal veins (arrows), which are depicted as linear signal intensity voids converging on the surface of the lateral ventricles. Also note the cortical penetrating veins (white arrowheads). A indicates anterior; L, lateral; M, medial; and P, posterior.