ISMRM 23rd Annual Meeting & Exhibition • 30 May - 05 June 2015 • Toronto, Ontario, Canada

Scientific Session • Diffusion Phantoms & Validation

Monday 1 June 2015

Constitution Hall 107

14:15 - 16:15


Markus Nilsson, Ph.D., T.B.A.

14:15 0151.   
Validation of orientation distribution functions in 3D using confocal microscopy
Kurt Schilling1, Yurui Gao1, Vaibhav Janve1, Iwona Stepniewska2, Prasanna Parvathaneni3, Hua Li1, Bennett A Landman4, and Adam W Anderson1
1VUIIS, Vanderbilt University, Nashville, TN, United States, 2Psychology, Vanderbilt University, Nasvhille, United States, 3Electrical Engineering, Vanderbilt University, TN, United States, 4Electrical Engineering, Vanderbilt University, Nashville, TN, United States

Validation of fiber orientation and anisotropy estimates from diffusion MRI (dMRI) studies has so far been limited to 2D analysis of histological sections. Here, we use structure tensor analysis to extract the 3D histological fiber orientation distribution (FOD) from confocal z-stacks, which then serves as a gold standard for comparisons with various dMRI acquisition protocols and signal models. Our results show good agreement between histological and dMRI estimates of fiber orientation in voxels containing nearly parallel fibers. Further, we find that Q-ball and DSI analysis are also able to resolve crossing fibers with similar accuracy.

14:27 0152.   Diffusivity in crossing and diverging fibers: a multi-site phantom experiment
Matthan W.A. Caan1, Ezequiel Farrher2, James Cole3, Dirk H.J. Poot4,5, Farida Grinberg2,6, and N. Jon Shah2,6
1Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Institute of Neuroscience and Medicine-4, Forschungszentrum Juelich, Juelich, Germany, 3Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, London, United Kingdom, 4Quantitative Imaging Group, Department of Imaging Physics, Delft University of Technology, Delft, Netherlands, 5Biomedical Imaging Group Rotterdam, Erasmus MC, Rotterdam, Netherlands, 6Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany

We studied diffusion parameters within a multisection diffusion phantom with parallel, diverging and crossing fibers, of which HARDI data were acquired on two 3 Tesla scanners. The single tensor model, a constrained dual tensor (DT) model and diffusion kurtosis imaging (DKI) were employed. Diffusion parameter profiles were computed in fibers tracked in different parts of the phantom. The DT model and DKI were more sensitive to minor microstructural changes. Comparing data between scanners shows an offset smaller than one standard deviation in all parameters. This approach gives insights into which parameters are most appropriate for multi-site human studies.

14:39 0153.   
Characterization of the Wallerian degeneration process in the rat spinal cord with DIAMOND and NODDI: comparison with histological obervations.
Damien Jacobs1, Benoit Scherrer2, Aleksandar Jankovski3, Anne des Rieux4, Maxime Taquet1, Bernard Gallez4, Simon K. Warfield2, and Benoit Macq1
1ICTEAM, Universite catholique de Louvain, Louvain-La-Neuve, Belgium, 2Computational Radiology Laboratory, Boston Childrens Hospital, Massachusetts, United States, 3Hopital universitaire Mont-Godinne, Universite catholique de Louvain, Godinne, Belgium, 4LDRI, Universite catholique de Louvain, Brussels, Belgium

The purpose is to investigate, for diffusion compartment models (NODDI and DIAMOND), the variations of diffusion parameters after Wallerian degeneration in the rat spinal cord. The values of diffusion parameters for NODDI and DIAMOND provide different informations and both models are investigated in the case of the Wallerian degeneration process. The alterations of each diffusion parameters are highlighted after an unilateral rhizotomy and the results are compared with the histological observations (myelin, neurofilaments, microglia, astrocytes).

14:51 0154.   
Quantitative histological correlates of NODDI orientation dispersion estimates in the human spinal cord
Francesco Grussu1, Torben Schneider1, Richard L. Yates2, Mohamed Tachrount3, Hui Zhang4, Daniel C. Alexander4, Gabriele C. DeLuca2, and Claudia A. M. Wheeler-Kingshott1
1NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, London, England, United Kingdom,2Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, England, United Kingdom, 3Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, England, United Kingdom, 4Department of Computer Science and Centre for Medical Image Computing, University College London, London, England, United Kingdom

Neurite orientation dispersion is an important morphological feature at the MRI voxel scale even in coherent areas such as the corpus callosum. In this work, we investigate its importance in another organised area: the human spinal cord. We estimate orientation dispersion in an ex vivo specimen with neurite orientation dispersion and density imaging (NODDI) at 9.4 T, and compare results with structure tensor features of silver stained sections from the same sample. We conclude that orientation dispersion is a key microstructural characteristic also of the spinal cord, and NODDI is a reliable technique for its quantification.

15:03 0155.   Validation of double diffusion schemes of microscopic fractional anisotropy
Henrik Lundell1, Tim B. Dyrby1, Penny L. Hubbard Cristinacce2,3, Feng-Lei Zhou2,4, Geoffrey J.M. Parker2,3, and Sune N. Jespersen5,6
1Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark, 2Centre for Imaging Sciences, The University of Manchester, United Kingdom, 3Biomedical Imaging Institute, The University of Manchester, United Kingdom, 4The School of Materials, The University of Manchester, United Kingdom, 5CFIN/MINDLab, Aarhus University, Denmark, 6Department of Physics and Astronomy, Aarhus University, Denmark

Double diffusion encoding pulse sequences (also known as double PFG) have been shown to detect microscopic diffusion anisotropy in macroscopically isotropic systems. Here we present and validate three sets of gradient direction schemes to measure microscopic diffusion anisotropy (e.g. µFA) in the presence of macroscopic anisotropy. In a phantom of co-electro-spun fibers, our results demonstrate similar performance of the three schemes, and show how µFA and FA together inform about microscopic anisotropy and fiber dispersion in a model independent fashion.

15:15 0156.   Estimating microstructural properties of a biomimetic tumour tissue phantom using diffusion-weighted MRI
Damien J McHugh1,2, Fenglei Zhou1,3, Penny L Hubbard Cristinacce1,2, Josephine H Naish1,2, and Geoff J M Parker1,2
1Centre for Imaging Sciences, The University of Manchester, Manchester, United Kingdom, 2Biomedical Imaging Institute, The University of Manchester, Manchester, United Kingdom, 3Materials Science Centre, The University of Manchester, Manchester, United Kingdom

In this work we introduce a novel phantom with microstructural characteristics mimicking tumour cellular structure, consisting of a collection of roughly spherical polymer structures. A two-compartment biophysical model was applied to diffusion data acquired over a range of gradient strengths and diffusion times, allowing the size and volume fraction of the ‘cells’ to be estimated. The radius was slightly underestimated compared with that determined from scanning electron microscope measurements, the fitted volume fraction was plausible, and parameters were found to be estimated with reasonably good precision. Such phantoms may be useful for testing microstructural models of the diffusion signal, and for scanner and protocol calibration.

15:27 0157.   Reduction of Susceptibility-Induced Field Gradients in Anisotropic Diffusion Fibre Phantoms using Susceptibility Matching - permission withheld
Johannes Lindemeyer1, Ezequiel Farrher1, Farida Grinberg1,2, Ana-Maria Oros-Peusquens1, and N. Jon Shah1,2
1Institute of Neuroscience and Medicine 4, INM-4, Medical Imaging Physics, Forschungszentrum Jülich GmbH, Jülich, Germany, 2Faculty of Medicine, Department of Neurology, RWTH Aachen University, JARA, Aachen, Germany

In this work we present an approach to reduce the effect of microscopic, susceptibility-induced field gradients on diffusion metrics in artificial anisotropic fibre phantoms. The approach relies on the use of MgCl2 to match the magnetic susceptibility of the liquid to that of the fibres.

15:39 0158.   A processing pipeline and anisotropic diffusion phantom to calibrate DTI experiments
Alexandru V. Avram1, Michal E. Komlosh1,2, Alan S. Barnett1,2, Elizabeth Hutchinson1,2, Dan Benjamini1,3, and Peter J. Basser1
1Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD, United States, 2The Henry Jackson Foundation, Bethesda, MD, United States, 3Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel

Experimental design and environmental factors can bias the quantitation of anisotropic diffusion using DTI-derived metrics, such as FA, compromising the value of longitudinal data and multicenter clinical studies. We propose the use of a novel anisotropic diffusion phantom in conjunction with a general method for modeling the diffusion signal produced by that phantom using the details of the DWI pulse sequence and the multiple correlation function (MCF) framework. The well-defined and known microstructure of the phantom generates a wide range of DTI parameters that can be used to calibrate various DTI pulse sequences and optimize clinical DTI protocols.

15:51 0159.   A novel phantom for quantitative diffusion MRI based on acetone and deuterium oxide
Xiaoke Wang1, Scott B. Reeder2,3, and Diego Hernando2
1Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, United States, 2Radiology, University of Wisconsin, Madison, Wisconsin, United States, 3Medical Physics, University of Wisconsin, Madison, Wisconsin, United States

Phantoms exhibiting desired diffusion behavior could provide a controlled means for validation of quantitative diffusion MRI techniques. Ideally, such phantoms should possess a single-peak MR spectrum and ADC values over the entire physiological range at a controlled temperature. Recently proposed phantoms such as PVP and sucrose phantoms may not meet all of these requirements. The purpose of this study is to investigate the spectral diffusion behavior of sucrose and PVP phantoms, and propose acetone D2O mixture as an alternative. Sucrose phantom showed multiple spectral peaks. PVP phantom showed narrow ranged ADC. Acetone-D2O phantom meets the requirements described above.

16:03 0160.   Hyperpolarized gas MR diffusion simulations and experiments in realistic 3D models and phantoms of human acinar airways
Juan Parra-Robles1, Bart Veeckmans2, Madhwesha Rao1, James C Hogg3, and Jim M Wild1
1University of Sheffield, Sheffield, South Yorkshire, United Kingdom, 2Materialise, Leuven, Belgium, 3University of British Columbia, Vancouver, British Columbia, Canada

The validity of current theoretical models of hyperpolarized gas MR diffusion used to quantify lung microstructure is limited by their use of simplified geometries. This work describes de development of realistic geometric models of human lung microstructure based on micro-CT images of excised lung samples. These models are used in numerical simulations of gas MR diffusion and to create realistic phantoms by 3D printing, which are used in 3He MR experiments to validate modelling results. These models and phantoms provide a new simulation and experimental framework to develop new MR methods and theoretical models to study lung anatomy and physiology.