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Proceedings Paper

Simulation of susceptibility-induced distortions in fMRI
Author(s): Ning Xu; Yong Li; Cynthia B. Paschal; J. Christopher Gatenby; Victoria L. Morgan; David R. Pickens; Benoit M. Dawant; J. Michael Fitzpatrick
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Paper Abstract

It has been recently proposed that computer-simulated phantom images can be used to evaluate methods for fMRI preprocessing. It is widely recognized that Gradient-Echo Echo Planar Imaging (EPI), the most often used technique for fMRI, is strongly affected by field inhomogeneities. Accurate and realistic phantom images for use by the fMRI community for software evaluation and training must incorporate these distortions and account for the effects of head motion and respiration on the distortions. A method to generate realistic distortions caused by field inhomogeneity for the generation of an fMRI phantom is presented in this paper. Changes in field inhomogeneity due to motion are studied by means of adding motions to the brain model and calculating the induced field map numerically rather than measuring it experimentally. A fast analytic version of an MR simulation is used to generate distorted EPI images based on the calculated field maps. The new generated fMRI phantoms can be used to evaluate processing algorithms for fMRI study more accurately. We can appreciate the importance of distortions for fMRI phantom generation by simulating a distortion-free image and adding distortions afterwards. Validations are performed by comparing the calculated field maps with measured ones. In addition, we show the similarities between a simulated fMRI phantom and real EPI image from our MR scanner.

Paper Details

Date Published: 20 March 2006
PDF: 9 pages
Proc. SPIE 6144, Medical Imaging 2006: Image Processing, 61446I (20 March 2006);
Show Author Affiliations
Ning Xu, Vanderbilt Univ. (United States)
Yong Li, Vanderbilt Univ. (United States)
Cynthia B. Paschal, Vanderbilt Univ. (United States)
J. Christopher Gatenby, Vanderbilt Univ. (United States)
Victoria L. Morgan, Vanderbilt Univ. (United States)
David R. Pickens, Vanderbilt Univ. (United States)
Benoit M. Dawant, Vanderbilt Univ. (United States)
J. Michael Fitzpatrick, Vanderbilt Univ. (United States)

Published in SPIE Proceedings Vol. 6144:
Medical Imaging 2006: Image Processing
Joseph M. Reinhardt; Josien P. W. Pluim, Editor(s)

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