OPENING SESSION - ismrm

Monday AM
18:06 107. 16-Channel Parallel Transmission in the Human Brain at 9.4 Tesla: Initial Results
Xiaoping Wu 1 , J. Thomas Vaughan 1 , Kamil Ugurbil 1 , Pierre-Francois Van de Moortele 1
1 CMRR, University of Minnesota, Minneapolis, MN, United States
It has been shown that parallel transmission (pTx), which consists of playing different RF pulses through independent transmit (Tx)
channels, can be used to mitigate Tx B1 (B1+) nonuniformity and to achieve more homogeneous spatially selective RF excitation at
high magnetic field. We have previously reported a successful implementation of Transmit SENSE in the human brain at 9.4 T with
an 8 Tx channel system, which required addressing methodological issues such as k-space trajectory inaccuracies and large
susceptibility induced δB0. Recently, our 9.4T system has been upgraded with a 16 Tx channel console. Here we report preliminary
results of 2D (Transmit SENSE) and 3D (Spoke trajectories) pTx in the human brain at 9.4 T using a 16-channel RF coil.
18:18 108. Self-Refocused Adiabatic Pulse for Spin Echo Imaging at 7T
Priti Balchandani 1 , John Pauly 2 , Daniel Spielman 1
1 Radiology, Stanford University, Stanford, CA, United States; 2 Electrical Engineering, Stanford University,
Stanford, CA, United States
Adiabatic 180° pulses may be used to replace conventional 180° pulses in spin echo sequences to provide greater immunity to the
inhomogeneous B 1 -field at 7T. However, because the spectral profile of an adiabatic 180° pulse has non-linear phase, pairs of these
pulses are used for refocusing, resulting in increased SAR and longer minimum echo times. We have used the adiabatic SLR method
to generate a matched-phase 90° for an adiabatic 180° pulse to obviate the need for a second 180° pulse. The pulse pair was combined
into a single self-refocused pulse to achieve the minimum echo time, and phantom and in vivo experiments were performed to validate
pulse performance.
Diffusion Studies of Brain Anatomy
Victoria Hall 16:30-18:30 Moderators: Alexander L. G. Leemans and Carlo
Pierpaoli
16:30 109. In Vivo Measurement of Cortical Anisotropy by Diffusion-Weighted Imaging
Correlates with Cortex Type
Alfred Anwander 1 , André Pampel 1 , Thomas R. Knösche 1
1 Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
High resolution diffusion-weighted imaging in conjunction with highly sensitive phase array acquisition coils can identify different
anisotropic orientation depending on the cortex type. Motor cortex shows radial anisotropy while primary somatosensory cortex shows
tangential anisotropy. This might relate to a strong wiring between neighboring cortical areas.
16:42 110. Skeleton Thickness Biases Statistical Power in Skeleton-Based Analyses of Diffusion
MRI Data
Richard A E Edden 1,2 , Derek K. Jones 3
1 Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University,
Baltimore, MD, United States; 2 FM Kirby Research Center for Functional MRI, Kennedy Krieger Institute,
Baltimore, MD, United States; 3 CUBRIC, School of Psychology,, Cardiff University, Cardiff, Wales, United
Kingdom
DTI provides rotationally invariant information. Additionally, DTI acquisitions are optimised to ensure that data are statistically
rotationally invariant so that parameter variance is independent of the orientation of the fibre population within the brain. Against this
backdrop, we focus on skeletonization-based methods for group comparisons of DTI data and show that they can reintroduce
rotational dependence. Specifically, the power to detect group differences in a fibre can depend on its orientation. While the
cause/solution to this problem are trivial, the effect on statistical inference is not – and should be viewed in the light of the increasing
popularity of skeletonization-based methods.
16:54 111. Sex-Linked White Matter Microstructure of the Social and the Analytic Brain
Kun-Hsien Chou 1 , I-Yun Chen 2 , Chun-Wei Lan 3 , Ya-Wei Cheng 2 , Ching-Po Lin 2,3 , Woei-
Chyn Chu 1
1 Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2 Institute of
Neuroscience, National Yang-Ming University, Taipei, Taiwan; 3 Institute of Biomedical imaging and
Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
Empathizing, driven by the social brain, means the capacity to predict and to respond to the behavior of agents by inferring their
mental status with an appropriate emotion. Systemizing, based on the analytic brain, is the capacity to predict and to respond to the
behavior of non-agentive deterministic systems by analyzing input-operation-output relations and inferring the rules of systems.
However WM associated with the social and analytic brain as indicated by sex differences remains to be investigated. In this study, we
demonstrated WM microstructures with sexual dimorphism, which may reflected the neural underpinning of the social and analytic
brain.