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Novel spherical phantoms for Q‐ball imaging under in vivo conditions
Author(s) -
MoussaviBiugui Amir,
Stieltjes Bram,
Fritzsche Klaus,
Semmler Wolfhard,
Laun Frederik B.
Publication year - 2011
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.22602
Subject(s) - anisotropy , diffusion mri , ball (mathematics) , materials science , diffusion imaging , fractional anisotropy , optics , biomedical engineering , physics , nuclear magnetic resonance , magnetic resonance imaging , geometry , mathematics , medicine , radiology
For the validation of complex diffusion imaging techniques like q‐ball imaging that aim to resolve multiple fiber directions, appropriate phantoms are highly desirable. However, previous q‐ball imaging phantoms had diffusion anisotropies well below those of in vivo white matter. In this work, fiber phantoms of well‐defined geometry are presented. The fibers are wound on a spherical spindle yielding high packing densities and consequently high diffusion anisotropies (fractional anisotropy 0.93 ± 0.02 at b = 500 s/mm 2 ). Phantoms with 90° and 45° crossing angle were constructed both with two crossing types. In the “stacked” crossing, two fiber strings were wound consecutively to simulate two touching fibers, in the “interleaved” crossing, fibers were wound alternately. The stacked crossing allows the alteration of partial volumes, whereas the interleaved crossing provides constant partial volumes, allowing e.g. the easy alteration of the SNR by varying the slice thickness. Exemplary q‐ball imaging validation measurements using different b ‐values and slice thicknesses are presented. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.