FC12-03 - DTI-based in vivo mapping of subregions within the human hypothalamus

• Published in: European psychiatry Vol. 26; no. S2; p. 1878
• Main Authors: Schoenknecht, P, Anwander, A, Petzold, F, Schindler, S, Knoesche, T, Hegerl, U, Turner, R, Geyer, S
• Format: Journal Article
• Language: English
• Published: Elsevier SAS 2011
• Subjects: Internal Medicine; Psychiatry
• ISSN: 0924-9338; 1778-3585
• DOI: 10.1016/S0924-9338(11)73582-9

Introduction The hypothalamus is involved in many aspects of behavioral responses but parcellations of hypothalamic subnuclei have only been feasible in post-mortem brains. Thus it would be-from a clinical point of view-highly desirable if hypothalamic subnuclei could be delineated also noninvasively in living subjects. This study is a first step in this direction: We exploited the directionality information inherent in high-resolution DTI data to map subregions of the hypothalamus in healthy volunteers. directionality information using DTI data to map subregions of the hypothalamus. Methods We scanned 10 subjects with a Siemens 3 T scanner, acquired DTI and T1 scans. We computed the similarity of fiber orientations between all voxels and subjects, and clustered the similarity matrix in 3 regions using a k-means algorithm. Results The diffusion images showed anisotropic tissue orientation within the hypothalamus which was consistent across subjects. The clustering in 3 regions resulted in an anatomically coherent arrangement of clusters across hemispheres and subjects. In each ROI, we found an anterior, a posteromedial, and a lateral subdivision with consistent microscopic tissue orientations across subjects. Conclusion This is to our best knowledge the first study that demonstrates the fine-grained microstructural organization within the human hypothalamus noninvasively in living subjects.