This document summarizes a study on developing a probabilistic tractography and segmentation method to chart the human thalamus. The study used diffusion tensor imaging and probabilistic tractography to visualize cortico-thalamic connections. It then developed a statistical shape model of the mean thalamus atlas incorporating these connectivity maps. The method was able to align the atlas to individual subjects' geometry with sub-millimeter accuracy, outperforming conventional alignment methods. This individualized target mapping method could help guide image-guided neurosurgery of the thalamus.
6. What really causes anisotropic diffusion? Beaulieu C. The basis of anisotropic water diffusion in the nervous system - a technical review. NMR Biomed 2002;15:435-455 .
19. Further implications of probabilistic tracking Behrens et al. Non-invasive mapping of connections between human thalamus and cortex using diffusion imaging Nature Neuroscience 6 , 750 - 757 (2003) Jakab et al. Connectivity-based parcellation reveals interhemispheric differences in the insula Brain Topography – in press - (2011) “ Based on connection targets” “ Clustering based on similarities of connectome”
20. Donnerstag, 20. Oktober 2011 Departement/Institut/Gruppe MTT Sat., Gringel et al. 2009 7T T1-w Zürich Morel et al. 1997 fMRI - Hulme et al. 2010 DTI+SSM Atlas- Jakab et al. 2011?
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22. State of the art imaging of the thalamus with DTI Donnerstag, 20. Oktober 2011 D-ITET / COMPUTER VISION LABORATORY Diffusion tensor imaging and probabilistic tractography visualizes cortico-thalamic connections Top right images> Behrens et al. Non-invasive mapping of connections between human thalamus and cortex using diffusion imaging Nature Neuroscience 6 , 750 - 757 (2003) Clinical, 1.5T 3DT1 Gross, structural information
31. Cortico-thalamic connections depicted using probabilistic tractography. Points represent the center-of-gravities of each connectivity map. Axial (top) view, isometric 3d display.
32. Connections of the precentral and postcentral gyrus and the spatial relationship between connectivity-based landmarks and the MNI152-transformed Morel Atlas data (VLpv, VPLa, VPLp nuclei). Points represent the center-of-gravities of each connectivity map. Superior view, isometric 3d display.
33. Results – aligned maps and intrathalamic landmarks Donnerstag, 20. Oktober 2011 D-ITET / COMPUTER VISION LABORATORY Black outlines: SSM-matched thalamus atlas Red spot: somatosensory connections, VPL
34. Results – Comparison to ACPC matching Donnerstag, 20. Oktober 2011 D-ITET / COMPUTER VISION LABORATORY Blue: SSM-based target map Red: ACPC aligned thalamus atlas Comparison on 1.5 T clinical imaging and CORTICOTHALAMIC TRACTOGRAPHY VL nucleus (VLa, VLpv) Somatomotor connections Somatomotor connections
35. Results – Comparison to ACPC matching Donnerstag, 20. Oktober 2011 D-ITET / COMPUTER VISION LABORATORY Blue: SSM-based target map Red: ACPC aligned thalamus atlas Comparison on 7.0 T post mortem imaging CENTROMEDIAN NUCLEUS