TRADITIONAL POSTER - ismrm

Poster Sessions
1633. Measuring Isotropic Diffusion with Rotating Diffusion Gradients
Irvin Teh 1,2 , Xavier Golay 1,3 , David Larkman 2
1 Lab of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore; 2 Imaging Sciences Department, Imperial
College London, London, United Kingdom; 3 Institute of Neurology, University College London, London, United Kingdom
A diffusion-weighted fast spin echo periodically rotated overlapping parallel lines with enhanced reconstruction (DW-FSE-PROPELLER) sequence was
combined with a multiple axis Stejskal-Tanner diffusion weighting scheme that rotated and alternated across blades. This reduced the number of DW
acquisitions needed to acquire the mean apparent diffusion coefficient from three to one, halving the total acquisition time. This motion and distortion robust
method was tested in the in-vivo mouse brain and compared to previously proposed rotating DW strategies.
1634. Novel Diffusion-Diffraction Patterns in Double-PFG NMR Afford Accurate Microstructural
Information in Size Distribution Phantoms
Noam Shemesh 1 , Evren Özarslan 2 , Peter J. Basser 2 , Yoram Cohen 1
1 School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2 Section on Tissue Biophysics and Biomimetics, NICHD, National
Institutes of Health, Bethesda, MD, United States
Diffusion-diffraction minima, which convey important microstructural information, vanish from the signal decay in single-pulsed-field-gradient (s-PFG)
experiments conducted on specimens characterized by size distributions. The double-PFG (d-PFG) methodology, an extension of s-PFG, was recently
predicted to exhibit zero-crossings (analogous to s-PFG diffusion-diffraction minima) that would persist even when the specimen is characterized by a broad
size-distribution. We therefore studied the signal decay in both s- and d-PFG in size-distribution phantoms consisting of water-filled microcapillaries of
various sizes. We find that the diffusion-diffraction minima in s-PFG indeed vanish, while the zero-crossings in d-PFG indeed persist, allowing to extract
important microstructural information.
1635. Metrics for Distinguishing Axon Disorder from Demyelination in Regions of Decreased Fractional
Anisotropy
Christine Marie Zwart 1 , David H. Frakes 1,2 , Josef P. Debbins 3
1 School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States; 2 School of Electrical,
Computer, and Energy Engineering, Arizona State University, Tempe, AZ, United States; 3 Keller Center for Imaging Innovation, St.
Joseph's Hospital and Medical Center, Phoenix, AZ, United States
Many diseases of the white matter are accompanied by an observable decrease in fractional anisotropy as measured with Diffusion Tensor Imaging. This
decrease can be attributable to a general increase in extracellular space or an absence of collinearity with respect to axon orientations. For studying the
progression of diseases such as multiple sclerosis (demyelination) and epilepsy (disorder) we have developed a correlation based metric that distinguishes
between these processes.
Diffusion Artifacts & Reproducibility
Hall B Thursday 13:30-15:30
1636. Enhanced ICBM Diffusion Tensor Template of the Human Brain
Shengwei Zhang 1 , Huiling Peng 1 , Robert Dawe 1 , Konstantinos Arfanakis 1
1 Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States
The purpose of this study was to develop a diffusion tensor (DT) template that is more representative of the microstructure of the human brain, and more
accurately matches ICBM space than existing templates. This was achieved by normalizing 67 DT datasets with minimal artifacts using high-dimensional
non-linear registration. The normalization accuracy achieved for the 67 datasets was evaluated. The properties of the resulting template were compared to
those of the current state of the art. The new template was shown to be more representative of single-subject human brain diffusion characteristics, and more
accurately matches ICBM space than previously published templates.
1637. Variability of Diffusion Tensor Characteristics in Human Brain Templates: Effect of the Number of
Subjects Used for the Development of the Templates
Shengwei Zhang 1 , John D. Carew 2 , Konstantinos Arfanakis 1
1 Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States; 2 Dickson Institute for Health Studies, Carolinas
Healthcare System, Charlotte, NC, United States
Development of a diffusion tensor (DT) brain template that is not biased by the properties of a single subject requires averaging of the DT information from
multiple subjects. The purpose of this study was to investigate the variability of DT characteristics in templates developed using different numbers of
subjects. The variability of template DT properties decreased as the number of subjects increased. Furthermore, DT templates constructed from 30 subjects
demonstrated high stability in tensor properties of voxels with FA=(0.6,1]. When considering voxels with FA=(0.2-1], more than 60 subjects were necessary
in order to achieve sufficiently high stability in tensor properties.
1638. Assessing the Accuracy of Spatial Normalization of Diffusion Tensor Imaging Data in the Presence of
Image Artifacts
Anton Orlichenko 1 , Robert J. Dawe 2 , Huiling Peng 2 , Konstantinos Arfanakis 2
1 Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL, United States; 2 Biomedical Engineering, Illinois
Institute of Technology, Chicago, IL, United States
Use of diffusion tensor imaging (DTI) data with minimal image artifacts may enhance the accuracy of inter-subject spatial normalization. This effect was
investigated by comparing the coherence of primary eigenvectors after normalizing separately a) data with minimal artifacts, and b) data with typical field