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Visualization of tensor fields using superquadric glyphs
Author(s) -
Ennis Daniel B.,
Kindlman Gordon,
Rodriguez Ignacio,
Helm Patrick A.,
McVeigh Elliot R.
Publication year - 2005
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20318
Subject(s) - visualization , tensor (intrinsic definition) , diffusion mri , ellipsoid , orientation (vector space) , voxel , computer science , glyph (data visualization) , oblate spheroid , eigenvalues and eigenvectors , geometry , artificial intelligence , physics , mathematics , classical mechanics , magnetic resonance imaging , medicine , quantum mechanics , astronomy , radiology
The spatially varying tensor fields that arise in magnetic resonance imaging are difficult to visualize due to the multivariate nature of the data. To improve the understanding of myocardial structure and function a family of objects called glyphs, derived from superquadric parametric functions, are used to create informative and intuitive visualizations of the tensor fields. The superquadric glyphs are used to visualize both diffusion and strain tensors obtained in canine myocardium. The eigensystem of each tensor defines the glyph shape and orientation. Superquadric functions provide a continuum of shapes across four distinct eigensystems (λ i , sorted eigenvalues), λ 1 = λ 2 = λ 3 (spherical), λ 1 < λ 2 = λ 3 (oblate), λ 1 > λ 2 = λ 3 (prolate), and λ 1 > λ 2 > λ 3 (cuboid). The superquadric glyphs are especially useful for identifying regions of anisotropic structure and function. Diffusion tensor renderings exhibit fiber angle trends and orthotropy (three distinct eigenvalues). Visualization of strain tensors with superquadric glyphs compactly exhibits radial thickening gradients, circumferential and longitudinal shortening, and torsion combined. The orthotropic nature of many biologic tissues and their DTMRI and strain data require visualization strategies that clearly exhibit the anisotropy of the data if it is to be interpreted properly. Superquadric glyphs improve the ability to distinguish fiber orientation and tissue orthotropy compared to ellipsoids. Magn Reson Med 53:169–176, 2005. Published 2004 Wiley‐Liss, Inc.