Coveney, S. orcid.org/0000-0002-7134-3196, Afzali Deligani, M., Mueller, L. et al. (4 more authors) (Accepted: 2025) Robust constrained weighted least squares for in vivo human cardiac diffusion kurtosis imaging. Magnetic Resonance in Medicine. ISSN: 0740-3194 (In Press)
Abstract
Purpose
Cardiac diffusion tensor imaging (cDTI) can investigate the microstructure of heart tissue. At sufficiently high b-values, additional information on microstructure can be observed, but the data require a representation such as diffusion kurtosis imaging (DKI). cDTI is prone to image corruption, which is usually treated with shot-rejection but which can be handled more generally with robust estimation. Unconstrained fitting allows DKI parameters to violate necessary constraints on signal behaviour, causing errors in diffusion and kurtosis measures.
Methods
We developed robust constrained weighted least squares (RCWLS) specifically for DKI. Using in vivo cardiac DKI data from 11 healthy volunteers collected with a Connectom scanner up to b-value 1350 s/mm² , we compared fitting techniques with/without robustness and with/without constraints.
Results
Constraints, but not robustness, made a significant difference on all measures. Robust fitting corrected large errors for some subjects. RCWLS was the only technique that showed radial kurtosis to be larger than axial kurtosis for all subjects, which is expected in myocardium due to increased restrictions to diffusion perpendicular to the primary myocyte direction. For b = 1350 s/mm² , RCWLS gave the following measures across subjects: mean diffusivity (MD) 1.68 ± 0.050 ×10‾³mm² /s, fractional anisotropy (FA) 0.30 ± 0.013, mean kurtosis (MK) 0.36 ± 0.027, axial kurtosis (AK) 0.26 ± 0.027, radial kurtosis (RK) 0.42 ± 0.040, and RK/AK 1.65 ± 0.19.
Conclusion
Fitting techniques utilizing both robust estimation and convexity constraints, such as RCWLS, are essential to obtain robust and feasible diffusion and kurtosis measures from in vivo cardiac DKI.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | This is an author produced version of an article accepted for publication in Magnetic Resonance in Medicine, made available under the terms of the Creative Commons Attribution License (CC-BY), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds) |
Funding Information: | Funder Grant number Wellcome Trust 219536/Z/19/Z |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Aug 2025 12:53 |
Last Modified: | 06 Aug 2025 12:53 |
Status: | In Press |
Publisher: | Wiley |
Identification Number: | 10.1002/mrm.70037 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:230044 |