In this article, the authors review the application of diffusion tensor (DT) magnetic resonance (MR) imaging to demonstrate anatomical substructures that cannot be resolved by conventional structural imaging. They review the physical basis of DT imaging and provide illustrative anatomical examples. The DT imaging technique measures the self-diffusion, or random thermal motion, of the endogenous...

The aim of this work was to develop a simple and fast 3D MRI-based computer model of arrhythmia inducibility in porcine hearts with chronic infarct scar, and to further validate it using electrophysiology (EP) measures obtained in-vivo. The heart model was built from MRI scans (with voxel size smaller than 1mm) and had fiber directions extracted from diffusion tensor DT-MRI. We used a macroscop...

The effect of heart geometry and anisotropy on cardiac re-entry dynamics and self-termination is studied here in anatomically realistic computer simulations of human foetal heart. 20 weeks of gestational age human foetal heart isotropic and anisotropic anatomy models from diffusion tensor MRI data sets are used in the computer simulations. The fiber orientation angles of the heart were obtained...

Diffusion-tensor magnetic resonance imaging (DT-MRI) offers great potential for understanding structure-function relationships in human skeletal muscles. The purposes of this study were to demonstrate the feasibility of using in vivo human DT-MRI fiber tracking data for making pennation angle measurements and to test the hypothesis that heterogeneity in the orientation of the tibialis anterior ...

This paper reports fabrication of a magnetic resonance imaging (MRI) phantom created by stacking of multiple thin polydimethylsiloxane (PDMS) layers. PDMS is spin coated on SU-8 molds to obtain the desired layer thickness and imprints of the microchannel patterns that define the phantom geometry. This paper also identifies the unique challenges related to the fabrication and assembly of multipl...

radical resection of a pathological lesion along with the preservation of eloquent cerebral tissue is the principle goal of neurosurgery. brain lesions are usually diagnosed by conventional magnetic resonance imaging (mri), but this method is unable to describe the relationship between lesions and neighboring specific white matter (wm) tracts. diffusion tensor tractograghy (dtt) is a new sophis...

This paper discusses registration of diffusion tensor (DT) MRIs (magnetic resonance images). An existing method for registration of 3D intensity images, the multi-resolution elastic matching algorithm, [1-3], is adapted to work with this new data type. A method is described for extracting the appropriate reorientation of DTs to accompany warps of the image from the local displacement field. Fur...

Diffusion MRI has become an invaluable tool for studying white matter microstructure and brain connectivity. The emergence of quantitative susceptibility mapping and susceptibility tensor imaging (STI) has provided another unique tool for assessing the structure of white matter. In the highly ordered white matter structure, diffusion MRI measures hindered water mobility induced by various tissu...

This thesis develops a registration algorithm specifically for diffusion-tensor (DT) im­ ages. The proposed approach matches the tensor orientations to find the registration transformation. Early results show that local optimisation does not find the global minimum in registration of DT-MR brain images. Therefore, a global optimisation re­ gistration technique is also implemented. This thesis p...

We construct the components for a family of computational models of the electrophysiology of the human foetal heart from 60 days gestational age (DGA) to full term. This requires both cell excitation models that reconstruct the myocyte action potentials, and datasets of cardiac geometry and architecture. Fast low-angle shot and diffusion tensor magnetic resonance imaging (DT-MRI) of foetal hear...