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Optimal acquisition orders of diffusion-weighted MRI measurements

Cook, PA; Symms, M; Boulby, PA; Alexander, DC; (2007) Optimal acquisition orders of diffusion-weighted MRI measurements. J MAGN RESON IMAGING , 25 (5) 1051 - 1058. 10.1002/jmri.20905.

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Abstract

Purpose: To propose a new method to optimize the ordering of gradient directions in diffusion-weighted MRI so that partial scans have the best spherical coverage.Materials and Methods: Diffusion-weighted MRI often uses a spherical sampling scheme, which acquires images sequentially with diffusion-weighting gradients in unique directions distributed isotropically on the hemisphere. If not all of the measurements can be completed, the quality of diffusion tensors fitted to the partial scan is sensitive to the order of the gradient directions in the scanner protocol. If the directions are in a random order, then a partial scan parts sparsely and thus provide poor spherical coverage. We compare the results of ordering with previously published methods for optimizing the acquisition in simulation.Results: Results show that all methods produce similar results and all improve the accuracy of the estimated diffusion tensors significantly over unordered acquisitions.Conclusion: The new ordering method improves the spherical coverage of partial scans and has the advantage of maintaining the optimal coverage of the complete scan.

Type:Article
Title:Optimal acquisition orders of diffusion-weighted MRI measurements
DOI:10.1002/jmri.20905
Keywords:diffusion tensor, acquisition, gradient directions, neuroimaging, patient compliance, TENSOR MRI, SCHEMES
UCL classification:UCL > School of BEAMS > Faculty of Engineering Science > Computer Science

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