title: Human habenula segmentation using myelin content.
abstract: The habenula consists of a pair of small epithalamic nuclei located adjacent to the dorsomedial thalamus. Despite increasing interest in imaging the habenula due to its critical role in mediating subcortical reward circuitry, in vivo neuroimaging research targeting the human habenula has been limited by its small size and low anatomical contrast. In this work, we have developed an objective semi-automated habenula segmentation scheme consisting of histogram-based thresholding, region growing, geometric constraints, and partial volume estimation steps. This segmentation scheme was designed around in vivo 3 T myelin-sensitive images, generated by taking the ratio of high-resolution T1w over T2w images. Due to the high myelin content of the habenula, the contrast-to-noise ratio with the thalamus in the in vivo 3T myelin-sensitive images was significantly higher than the T1w or T2w images alone. In addition, in vivo 7 T myelin-sensitive images (T1w over T2*w ratio images) and ex vivo proton density-weighted images, along with histological evidence from the literature, strongly corroborated the in vivo 3 T habenula myelin contrast used in the proposed segmentation scheme. The proposed segmentation scheme represents a step toward a scalable approach for objective segmentation of the habenula suitable for both morphological evaluation and habenula seed region selection in functional and diffusion MRI applications.
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Electronic address: joo-won.kim@mssm.edu.
authors.forename: Joo-Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Naidich
authors.affiliation: Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Ely
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minnesota, MN, USA.
authors.forename: Essa
authors.initials: E
authors.lastname: Yacoub
authors.affiliation: Department of Cognitive Neurosciences, Faculty of Psychology and Neuroscience, Maastricht University, Netherlands.
authors.forename: Federico
authors.initials: F
authors.lastname: De Martino
authors.affiliation: Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Fowkes
authors.affiliation: Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Wayne K
authors.initials: WK
authors.lastname: Goodman
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minnesota, MN, USA. Electronic address: junqian.xu@mssm.edu.
authors.forename: Junqian
authors.initials: J
authors.lastname: Xu
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D019262:Habenula / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D009186:Myelin Sheath
keywords: Geometric constraints; Habenula; Myelin map; Myelin-sensitive image; Partial volume estimation; Region growing; Subcortical segmentation