Traditional Posters: Diffusion & Perfusion - ismrm

1659. Language Circuits of Human Brain: An Integrated Study of FMRI and
Probabilistic DTI
Zong-Kai Hsu 1 , Tzu-Chen Yeh 2,3 , Chou-Ming Cheng 2 , Wen-Jui Kuo 4 , Jen-Chuen Hsieh 5
1 Institute of Brain Science , National Yang Ming University , Taipei, Taiwan; 2 Laboratory of Integrated Brain
Research, Department of Medical Research & Education, Taipei Veterans General Hospital, Taipei, Taiwan;
3 Institute of Brain Science , National Yang Ming University, Taipei, Taiwan; 4 Institute of Neuroscience,
National Yang Ming University, Taipei, Taiwan; 5 Institute of Brain Science, National Yang Ming University,
Taipei, Taiwan
The language anatomical model proposed that Broca¡¦s area located in the inferior frontal lobe and Wernicke¡¦s area located in the
superior temporal gyrus were connected through the arcuate fasciculus (AF). Hickok and Poeppel [1] and others recently proposed a
dual stream model for auditory language processing. From the superior temporal gyrus, which is engaged in early cortical stages of
speech perception, the system diverges into two processing streams. The aim of this study is to examine the language circuits of the
dual stream model using visual perception by an integrated functional MRI (fMRI) and probabilistic diffusion tensor imaging (pDTI)
method.
1660. Resolution-Dependent Differences in Fiber Tracking and Quantification of the
Visual Pathways
Jan Klein 1 , Peter Erhard 2 , Horst Karl Hahn 1
1 Fraunhofer MEVIS, Bremen, Germany; 2 FB 2 (Chemistry) and Center of Advanced Imaging (CAI), Germany
Fiber tracking and quantification of the visual pathways is still a challenging problem due distortions in the vicinity of the optic nerve,
the small diameter of the bundle itself, crossing fibers in the optic chiasm and the capsula interna, the high curvature in the Meyers
loop, and the discontinuity in the corpus geniculatum laterale. We examine how changes in the resolution of the DTI data sets
influence the fiber tracking and quantification of the visual pathways, and show that an anisotropic resolution with a high coronal inplane
resolution should be preferred to an isotropic resolution with the same volume per voxel.
1661. Characterization of White Matter Fasciculi with T1 Quantification: A Feasibility
Study at High Field
Nico Dario Papinutto 1 , Jorge Jovicich 1
1 Center for Mind/Brain Sciences, University of Trento, Mattarello, Trento, Italy
Diffusion tensor imaging (DTI) of in-vivo human brains is a technique that is becoming widely used to get insight into normal and
abnormal white matter anatomical connectivity. Characterization of pathologies with fractional anisotropy (FA) losses have been
done, both at voxel level and along tracts. A promising method to further improve the characterization of main streamlines consists on
adding relaxation times measurements. We present a simple method for T1 quantification of white matter tracts using sequences
available in most commercial scanners.
1662. Gradual Variation of Anatomical Connectivity in the Macaque Insula Revealed by
Probabilistic Tractography
Leonardo Cerliani 1 , Helen D'Arceuil 2 , Rajat M. Thomas 3 , Saad Jbabdi 4 , Christian M.
Keysers 1
1 Neuroscience, University Medical Center Groningen, Neuroimaging Center, Groningen, Netherlands; 2 Dept. of
Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, United
States; 3 Kapteyn Astronomical Institute, University of Groningen, Netherlands; 4 FMRIB Centre, Univ. of
Oxford, John Radcliffe Hospital, United Kingdom
The connectivity of the macaque insula was analyzed by means of probabilistic tractography on diffusion-weighted images. The main
aim was to detect and analyze trajectories of connectivity variation in this brain region, and to test the consistency of the results with
the available anatomical evidence from animal literature. The employed method of laplacian eigenmaps was able to recover the
expected gradual change in connectivity, and to discriminate this with the sharp transition in connectivity featured by the medial motor
cortex
1663. Assessment of the Reproducibility of HARDI Tractography Based Cortical
Connectivity Measures Suitable for Clinical Populations Using a Bootstrap Approach
Kerstin Pannek 1,2 , Jane Mathias 3 , James Taylor 4 , Parnesh Raniga 5 , Olivier Salvado 5 ,
Stephen Rose 1,2
1 Centre for Magnetic Resonance, University of Queensland, Brisbane, Queensland, Australia; 2 UQ Centre for
Clinical Research, University of Queensland, Brisbane, Queensland, Australia; 3 School of Psychology,
University of Adelaide, Adelaide, South Australia, Australia; 4 Magnetic Resonance Imaging Unit, Royal
Adelaide Hospital, Adelaide, South Australia, Australia; 5 The Australian E-Health Research Centre, CSIRO,
Brisbane, Queensland, Australia
Structural connectivity of the brain using MR diffusion tractography has gained significant interest. A connectivity matrix of cortical
connectivity may provide unique insight into brain organisation. We aimed to develop a method to determine the number of seeds
required to obtain stable and reproducible connectivity, and to assess reproducibility over time. We employ a bootstrap approach for
estimation of these parameters. While connectivity measures of some regions are highly reproducible over time, other connections
show poor reproducibility. This study highlights the relationship between seed number and reproducibility of connectivity.