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Phantom‐based evaluation of geometric distortions in functional magnetic resonance and diffusion tensor imaging
Author(s) -
Mattila Seppo,
Renvall Ville,
Hiltunen Jaana,
Kirven Douglas,
Sepponen Raimo,
Hari Riitta,
Tarkiainen Antti
Publication year - 2007
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.21218
Subject(s) - imaging phantom , diffusion mri , magnetic resonance imaging , scanner , orientation (vector space) , echo planar imaging , nuclear magnetic resonance , biomedical engineering , computer science , distortion (music) , nuclear medicine , physics , artificial intelligence , medicine , mathematics , radiology , geometry , amplifier , computer network , bandwidth (computing)
Phantom‐based evaluation of geometric distortions in functional MRI and diffusion tensor imaging (DTI) was investigated. An acrylic water‐filled phantom with a grid structure was designed and manufactured to provide accurate geometric information over the volume measured in human brain imaging. The grid structures were well detected in data acquired using a 3‐T MRI scanner with echo‐planar imaging (EPI) sequences commonly applied in functional MRI and DTI. A method for quantifying distortions in the phantom data was presented and applied for the images. The validity of the phantom for EPI was evaluated by quantitatively comparing the distortions present in and induced by the phantom and a human brain when imaged under identical conditions. The results suggest that the new phantom can reveal geometric distortions easily undermined by standard MRI phantoms. For example, prominent variability in the distortions was found as a function of the orientation of the diffusion‐sensitizing gradient. Possible future applications for this type of phantom include quality assurance and calibration of the hardware and software used in EPI‐based functional MRI and DTI. Magn Reson Med 57:754–763, 2007. © 2007 Wiley‐Liss, Inc.