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Reconstruction after Rotational Motion

Atkinson, D; Hill, DLG; (2003) Reconstruction after Rotational Motion. Magnetic Resonance in Medicine , 49 (1) pp. 183-187. 10.1002/mrm.10333.

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Patient rotational motion during a scan causes the k-space sampling to be both irregular and undersampled. Conventional regridding requires an estimate of the sampling density at each measured point and is not strictly consistent with sampling theory. Here, a 2D problem is converted to a series of 1D regriddings by exact interpolation along the measured readouts. Each 1D regridding, expressed in matrix form, requires a matrix inversion to gain an exact solution. Undersampled regions make the matrix ill-conditioned but summing the matrix columns (without inversion) indicates the undersampled regions. The missing data could be reacquired, but in this study it is estimated using a Delaunay triangle-based linear interpolation on the original 2D data. The matrix conditioning is improved, leading to images with reduced artifacts compared to other regridding schemes. Furthermore, there is no requirement to estimate a density compensation function at each of the measured points

Type: Article
Title: Reconstruction after Rotational Motion
DOI: 10.1002/mrm.10333
Keywords: Head, anatomy & histology, Humans, Image Processing, Computer-Assisted, methods, Magnetic Resonance Imaging, Research Support, Non-U.S.Gov't, Rotation
UCL classification: UCL > School of Life and Medical Sciences
UCL > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Engineering Science
URI: http://discovery.ucl.ac.uk/id/eprint/2840
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