title: High-Resolution MR Imaging of the Human Brainstem In vivo at 7 Tesla.
abstract: The human brainstem, which comprises a multitude of axonal nerve fibers and nuclei, plays an important functional role in the human brain. Depicting its anatomy non-invasively with high spatial resolution may thus in turn help to better relate normal and pathological anatomical variations to medical conditions as well as neurological and peripheral functions. We explored the potential of high-resolution magnetic resonance imaging (MRI) at 7 T for depicting the intricate anatomy of the human brainstem in vivo by acquiring and generating images with multiple contrasts: T 2-weighted images, quantitative maps of longitudinal relaxation rate (R 1 maps) and effective transverse relaxation rate ([Formula: see text] maps), magnetic susceptibility maps, and direction-encoded track-density images. Images and quantitative maps were compared with histological stains and anatomical atlases to identify nerve nuclei and nerve fibers. Among the investigated contrasts, susceptibility maps displayed the largest number of brainstem structures. Contrary to R 1 maps and T 2-weighted images, which showed rather homogeneous contrast, [Formula: see text] maps, magnetic susceptibility maps, and track-density images clearly displayed a multitude of smaller and larger fiber bundles. Several brainstem nuclei were identifiable in sections covering the pons and medulla oblongata, including the spinal trigeminal nucleus and the reticulotegmental nucleus on magnetic susceptibility maps as well as the inferior olive on R 1, [Formula: see text], and susceptibility maps. The substantia nigra and red nuclei were visible in all contrasts. In conclusion, high-resolution, multi-contrast MR imaging at 7 T is a versatile tool to non-invasively assess the individual anatomy and tissue composition of the human brainstem.
authors.affiliation: Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Center of Radiology, Jena University Hospital - Friedrich Schiller University Jena , Jena , Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Deistung
authors.forename: Andreas
authors.initials: A
authors.lastname: Schäfer
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Schweser
authors.forename: Uta
authors.initials: U
authors.lastname: Biedermann
authors.forename: Daniel
authors.initials: D
authors.lastname: Güllmar
authors.forename: Robert
authors.initials: R
authors.lastname: Trampel
authors.forename: Robert
authors.initials: R
authors.lastname: Turner
authors.forename: Jürgen R
authors.initials: JR
authors.lastname: Reichenbach
keywords: anatomy; brain; brainstem; diffusion tensor imaging; effective transverse relaxation; longitudinal relaxation; quantitative susceptibility mapping; track-density imaging