Effects of image reconstruction on fiber orientation mapping from multichannel diffusion MRI: reducing the noise floor using SENSE

Sotiropoulos, S.N.; Moeller, S.; Jbabdi, S.; Xu, J.; Andersson, J.L.; Auerbach, E.J.; Yacoub, E.; Feinberg, D.; Setsompop, K.; Wald, L.L.; Behrens, T.E.J.; Ugurbil, K.; Lenglet, C.

Abstract

Purpose: To examine the effects of the reconstruction algorithm of magnitude images from multi-channel diffusion MRI on fibre orientation estimation.
Theory and Methods: It is well established that the method used to combine signals from different coil elements in multi-channel MRI can have an impact on the properties of the reconstructed magnitude image. Utilising a root-sum-of-squares (RSoS) approach results in a magnitude signal that follows an effective non-central-distribution. As a result, the noise floor, the minimum measurable in the absence of any true signal, is elevated. This is particularly relevant for diffusion-weighted MRI, where the signal attenuation is of interest.
Results: In this study, we illustrate problems that such image reconstruction characteristics may cause in the estimation of fibre orientations, both for model-based and model-free approaches, when modern 32-channel coils are employed. We further propose an alternative image reconstruction method that is based on sensitivity encoding (SENSE) and preserves the Rician nature of the single-channel, magnitude MR signal. We show that for the same k-space data, RSoS can cause excessive overfitting and reduced precision in orientation estimation compared to the SENSE-based approach.
Conclusion: These results highlight the importance of choosing the appropriate image reconstruction method for tractography studies that use multi-channel receiver coils for diffusion MRI acquisition.

Citation

Sotiropoulos, S., Moeller, S., Jbabdi, S., Xu, J., Andersson, J., Auerbach, E., …Lenglet, C. (2013). Effects of image reconstruction on fiber orientation mapping from multichannel diffusion MRI: reducing the noise floor using SENSE. Magnetic Resonance in Medicine, 70(6), https://doi.org/10.1002/mrm.24623

• Journal Article Type: Article
• Acceptance Date: Dec 9, 2012
• Online Publication Date: Feb 7, 2013
• Publication Date: Nov 18, 2013
• Deposit Date: Jul 11, 2018
• Publicly Available Date: Jul 11, 2018
• Journal: Magnetic Resonance in Medicine
• Print ISSN: 0740-3194
• Electronic ISSN: 1522-2594
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 70
• Issue: 6
• DOI: https://doi.org/10.1002/mrm.24623
• Keywords: Sum of Squares; SENSE; Rician; Non-central-X; Magnitude Image; Tractography
• Public URL: https://nottingham-repository.worktribe.com/output/719347
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/mrm.24623
• Additional Information: This is the peer reviewed version of the following article, which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1002/mrm.24623. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.