MRI Atlas of the Human Deep Brain

Abstract

Mastering detailed anatomy of the human deep brain in clinical neurosciences is challenging. Although numerous pioneering works have gathered a large dataset of structural and topographic information, it is still difficult to transfer this knowledge into practice, even with advanced magnetic resonance imaging techniques. Thus, classical histological atlases continue to be used to identify structures for stereotactic targeting in functional neurosurgery. Physicians mainly use these atlases as a template co-registered with the patient's brain. However, it is possible to directly identify stereotactic targets on MRI scans, enabling personalized targeting. In order to help clinicians directly identify deep brain structures relevant to present and future medical applications, we built a volumetric MRI atlas of the deep brain (MDBA) on a large scale (infra millimetric). Twelve hypothalamic, 39 subthalamic, 36 telencephalic, and 32 thalamic structures were identified, contoured, and labeled. Nineteen coronal, 18 axial, and 15 sagittal MRI plates were created. Although primarily designed for direct labeling, the anatomic space was also subdivided in twelfths of AC-PC distance, leading to proportional scaling in the coronal, axial, and sagittal planes. This extensive work is now available to clinicians and neuroscientists, offering another representation of the human deep brain ([https://hal.archives-ouvertes.fr/] [hal-02116633]). The atlas may also be used by computer scientists who are interested in deciphering the topography of this complex region.

Keywords: MRI; atlas; deep brain; human; hypothalamus; stereotaxis; subthalamus; thalamus.

Figure 1

Principle of contouring and voxel objects (frontal view; coronal slices). (A) ventrocaudal medial nucleus of thalamus (pink). (B) retrolenticular-reticularoïd zone (light beige). (C) smoothed surfaces of voxel objects, ventrocaudal medial nucleus of thalamus, retrolenticular-reticularoïd zone, red nucleus (red), and hippocampal formation (light brown).

Figure 2

(A) Contouring and labeling of the retrolenticular reticularoid zone (RLRZ; the voxel object is overlaid) on MRI slice (see MDBA plate 10); medial geniculate body, M-GB; lateral geniculate body, L-GB; stria terminalis, STR-ter; caudate nucleus, CAU-nu. (B) Same region according to Riley (36); the RLRZ is visible (histologic preparation) but not identified. (C) Same region according to Dejerine (26); the RLRZ is visible (artist drawing) but not identified.

Figure 3

(A) Colored surfaces and acronyms, plate CR8 (millimeter scale), the ACPC line is depicted as a black circle. (B) Same plate, colors are specified according to subregions (proportional and millimeter scales); thalamus (blue gradation), subthalamus (brown gradation) and telencephalon (green gradation). (C) Same plate, MRI slice and white contours of structures (no scale).

Figure 4

Position of slices (colored lines: axial, red; coronal, blue; sagittal, green) on the axial ACPC plan (A0-ACPC; left row), coronal MI plan (CR6-MI; intermediate row) and 9-mm lateral sagittal plan (S4; right row); proportional grid (purple) in 12th of ACPC distance; HT, thalamus height.