FIG. 1.

Magnetic resonance imaging (MRI) contrast for in vivo delineation of several human brainstem nuclei (Bn). The fractional anisotropy (FA) map (coronal view shown) computed from 1.1 mm isotropic diffusion-weighted MRI data at an ultra-high magnetic field (∼24 min acquisition, example dataset, native echo-planar-imaging (EPI) space) displays good gray matter–white matter contrast in the brainstem, which provides complementary information to relaxivity-based (T2-, T2*-, and T1-weighted) MRI. On the FA map, the locations of several Bn are indicated: periaqueductal gray (PAG, pink arrow), mesencephalic tegmental nuclei (yellow arrows), raphe nuclei (green arrows), pontine nuclei (blue arrows), and inferior olivary nuclei (ION, red arrows).