Diffusion-Tensor MRI is a technique allowing the measurement of the water molecule motion in the tissues fibers, by the mean of rendering multiple MRI images under different oriented magnetic fields. This large set of raw data is then further estimated into a volume of diffusion tensors (i.e. 3 × 3 symmetric and positive-definite matrices) that describe through their spectral elements, the diff...

In this report, we present a kernel-based approach to the clustering of diffusion tensors in images of the human skeletal muscle. Based on the physical intuition of tensors as a means to represent the uncertainty of the position of water protons in the tissues, we propose a Mercer (i.e. positive definite) kernel over the tensor space where both spatial and diffusion information are taken into a...

In this article, we introduce nonlinear versions of the popular structure tensor, also known as second moment matrix. These nonlinear structure tensors replace the Gaussian smoothing of the classical structure tensor by discontinuity-preserving nonlinear diffusions. While nonlinear diffusion is a well-established tool for scalar and vector-valued data, it has not often been used for tensor imag...

Introduction Steady-state diffusion-weighted imaging enables high-SNR, high-resolution diffusion images of brain and is potentially effective in the diagnosis of stroke location [1]. However, white matter anisotropic tissue contrast can mask out a real stroke location. In order to get rid of the anisotropic effect of diffusion, the whole diffusion tensor is acquired and its trace is derived. Al...

INTRODUCTION: Diffusion tensor imaging (DTI) is capable of non-invasively measuring water diffusion in vivo. While DTI has been widely em delineate potential white matter abnormality in different neurological diseases, registration of diffusion tensor images across different subjects i prerequisite for detailed statistical analysis on voxel-by-voxel basis. However, spatial normalization of diff...

Within biological systems water molecules undergo continuous stochastic Brownian motion. The rate of this diffusion can give clues to the structure of underlying tissues. In some tissues the rate is anisotropic – faster in some directions than others. Diffusion-rate images are second-order tensor fields and can be calculated from diffusion-weighted magnetic resonance images. A 2D diffusion tens...

In this report, we propose a novel diffusion tensor registration algorithm based on a discrete optimization approach in a Reproducing Kernel Hilbert Space (RKHS) setting. Our approach encodes both the diffusion information and the spatial localization of tensors in a probabilistic framework. The diffusion probabilities are mapped to a RKHS, where we define a registration energy that accounts bo...

A. Leemans, J. Sijbers, M. Verhoye, A. Van der Linden Physics, University of Antwerp, Antwerp, Belgium, Biomedical Sciences, University of Antwerp, Antwerp, Belgium Introduction and Purpose Diffusion tensor magnetic resonance imaging (DT-MRI) is becoming an important diagnostic tool for various neuropathological diseases [1, 2]. It is often desirable to combine multiple DT-MRI data sets of the ...

Intraoperative line scan diffusion imaging (LSDI) on a 0.5 Tesla interventional MRI was performed during neurosurgery in three patients. Diffusion trace images were obtained in acute ischemic cases. Scan time per slice was 46 seconds and 94 seconds, respectively, for diffusion tensor images. Diagnosis of acutely developed vascular occlusion was confirmed with follow-up scans. White matter tract...

Accurate extraction of cardiac fiber orientation from diffusion tensor imaging is important for determining heart structure and function. However, the acquisition of magnetic resonance (MR) diffusion tensor images is costly and time consuming. By comparison, cardiac ultrasound imaging is rapid and relatively inexpensive, but it lacks the capability to directly measure fiber orientations. In ord...