Two Canonical Representations for Regularized High Angular Resolution Diffusion Imaging
نویسندگان
چکیده
Two canonical representations for regularization of unit sphere functions encountered in the context of high angular resolution diffusion imaging (HARDI) are discussed. One of these is based on spherical harmonic decomposition, and its one-parameter extension via Tikhonov regularization. This case is well-established, and is mainly reviewed for the sake of completeness. The second one is new, and is based on a higher order diffusion tensor decomposition. A homogeneous representation of this type has been proposed in the literature, but we show that this is inconvenient for the purpose of regularization. We instead construct a heterogeneous representation that can be regarded as “canonical”, to the extent that its behaviour under regularization mimics that of spherical harmonics.
منابع مشابه
Determination of Fiber Direction in High Angular Resolution Diffusion Images using Spherical Harmonics Functions and Wiener Filter
Diffusion tensor imaging (DTI) MRI is a noninvasive imaging method of the cerebral tissues whose fibers directions are not evaluated correctly in the regions of the crossing fibers. For the same reason the high angular resolution diffusion images (HARDI) are used for estimation of the fiber direction in each voxel. One of the main methods to specify the direction of fibers is usage of the spher...
متن کاملVisualization of High Angular Resolution Diffusion MRI Data with Color-Coded LIC-Maps
In diffusion MRI a voxel's local diffusion profile may be visualized in detail by glyph-based techniques, e.g. ellipsoidal or superquadric tensor glyphs. Global representations, such as streamlines and streamtubes, provide fiber continuity, but may lead to misinterpretations due to deficiences of the tractography algorithm used. Line integral convolution (LIC) has been applied to diffusion tens...
متن کاملRegularized, fast, and robust analytical Q-ball imaging.
We propose a regularized, fast, and robust analytical solution for the Q-ball imaging (QBI) reconstruction of the orientation distribution function (ODF) together with its detailed validation and a discussion on its benefits over the state-of-the-art. Our analytical solution is achieved by modeling the raw high angular resolution diffusion imaging signal with a spherical harmonic basis that inc...
متن کاملEfficient Global Spatial-Angular Sparse Coding for Diffusion MRI with Separable Dictionaries
Diffusion MRI (dMRI) provides the ability to reconstruct neuronal fibers in the brain, in vivo, by measuring water diffusion along angular gradient directions in q-space. High angular resolution diffusion imaging (HARDI) can produce better estimates of fiber orientation than the popularly used diffusion tensor imaging, but the high number of samples needed to estimate diffusivity requires lengt...
متن کاملTime-Optimized High-Resolution Readout-Segmented Diffusion Tensor Imaging
Readout-segmented echo planar imaging with 2D navigator-based reacquisition is an uprising technique enabling the sampling of high-resolution diffusion images with reduced susceptibility artifacts. However, low signal from the small voxels and long scan times hamper the clinical applicability. Therefore, we introduce a regularization algorithm based on total variation that is applied directly o...
متن کامل