Journal ArticleDOI
Mapping eddy current induced fields for the correction of diffusion-weighted echo planar images.
Mark A. Horsfield
- Vol. 17, Iss: 9, pp 1335-1345
TLDR
A method is presented to measure the magnetic fields generated from the eddy currents for each of three orthogonal gradient pulse vectors, and then to ascertain the image distortion that occurs in subsequent diffusion-weighted images with arbitrary gradient pulse vector amplitude and direction.Abstract:
Diffusion-weighted echo-planar magnetic resonance imaging is potentially of great importance as a diagnostic imaging tool; however, the technique currently suffers a number of limitations, including the image distortion caused by the eddy current induced fields when the diffusion-weighting magnetic field gradient pulses are applied. The distortions cause mis-registration between images with different diffusion-weighting, that then results in artifacts in quantitative diffusion images. A method is presented to measure the magnetic fields generated from the eddy currents for each of three orthogonal gradient pulse vectors, and then to use these to ascertain the image distortion that occurs in subsequent diffusion-weighted images with arbitrary gradient pulse vector amplitude and direction, and image plane orientation. The image distortion can then be reversed. Both temporal and spatial dependence of the residual eddy current induced fields are included in the analysis. Image distortion was substantially reduced by the correction scheme, for arbitrary slice position and angulation. This method of correction is unaffected by the changes in image contrast that occur due to diffusion weighting, and does not need any additional scanning time during the patient scan. It is particularly suitable for use with single-shot echo planar imaging.read more
Citations
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Journal ArticleDOI
Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data.
Stephen M. Smith,Mark Jenkinson,Heidi Johansen-Berg,Daniel Rueckert,Thomas E. Nichols,Clare E. Mackay,Kate E. Watkins,Olga Ciccarelli,M Z Cader,Paul M. Matthews,Timothy E.J. Behrens +10 more
TL;DR: TBSS aims to improve the sensitivity, objectivity and interpretability of analysis of multi-subject diffusion imaging studies by solving the question of how to align FA images from multiple subjects in a way that allows for valid conclusions to be drawn from the subsequent voxelwise analysis.
Journal ArticleDOI
Mutual-information-based registration of medical images: a survey
TL;DR: An overview is presented of the medical image processing literature on mutual-information-based registration, an introduction for those new to the field, an overview for those working in the field and a reference for those searching for literature on a specific application.
Journal ArticleDOI
An integrated approach to correction for off-resonance effects and subject movement in diffusion MR imaging
TL;DR: The method is based on registering the individual volumes to a model free prediction of what each volume should look like, thereby enabling its use on high b-value data where the contrast is vastly different in different volumes.
Journal ArticleDOI
Diffusion-Weighted Magnetic Resonance Imaging as a Cancer Biomarker: Consensus and Recommendations
Anwar R. Padhani,Guoying Liu,Dow Mu-Koh,Thomas L. Chenevert,Harriet C. Thoeny,Taro Takahara,Andrew Dzik-Jurasz,Brian D. Ross,Marc Van Cauteren,David J. Collins,Dima A. Hammoud,Gordon J. S. Rustin,Bachir Taouli,Peter L. Choyke +13 more
TL;DR: DW-MRI should be tested as an imaging biomarker in the context of well-defined clinical trials, by adding DW-MRI to existing NCI-sponsored trials, particularly those with tissue sampling or survival indicators, and standards for measurement, analysis, and display are needed.
Journal ArticleDOI
Diffusion-tensor MRI: theory, experimental design and data analysis - a technical review.
Peter J. Basser,Derek K. Jones +1 more
TL;DR: In this article, the theoretical underpinnings of diffusion-tensor magnetic resonance imaging (DT-MRI), as well as experimental design and data analysis issues are discussed. And new statistical methods have been developed to analyse DT-MRI data, and their potential uses in clinical and multi-site studies.
References
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Journal ArticleDOI
Optimal strategies for measuring diffusion in anisotropic systems by magnetic resonance imaging.
TL;DR: An algorithm is presented that minimizes the bias inherent in making measurements with a fixed set of gradient vector directions by spreading out measurements in 3‐dimensional gradient vector space and this results in reduced scan times, increased precision, or improved resolution in diffusion tensor images.