Model-based analysis of multi-shell diffusion MR data for tractography: How to get over fitting problems

By Saâd Jbabdi, Stamatios N. Sotiropoulos, Alex Manhaes Savio, Manuel Graña, Timothy Edward John Behrens. Magnetic Resonance in Medicine, 2012

397 citations recorded by the source corpus.

In this article, we highlight an issue that arises when using multiple b‐values in a model‐based analysis of diffusion MR data for tractography. The non‐monoexponential decay, commonly observed in experimental data, is shown to induce overfitting in the distribution of fiber orientations when not considered in the model. Extra fiber orientations perpendicular to the main orientation arise to compensate for the slower apparent signal decay at higher b‐values. We propose a simple extension to the ball and stick model based on a continuous gamma distribution of diffusivities, which significantly improves the fitting and reduces the overfitting. Using in vivo experimental data, we show that this model outperforms a simpler, noise floor model, especially at the interfaces between brain tissues, suggesting that partial volume effects are a major cause of the observed non‐monoexponential decay. This model may be helpful for future data acquisition strategies that may attempt to combine multiple shells to improve estimates of fiber orientations in white matter and near the cortex. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.

Subfields: Orthopedics and Sports Medicine, Radiology, Nuclear Medicine and Imaging

View Paper: https://www.semanticscholar.org/paper/96fc94f7c98fc1bf400f81f7352ff8e7d9f61e15

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Citations in the corpus

Hierarchical Heterogeneity across Human Cortex Shapes Large-Scale Neural Dynamics (2018, positive): “Following the HCP dMRI step, the diffusion images were underwent FSL’s bedpostx and probtrackx2 analysis workflows for probabilistic tractography.”
Sex differences in the adult human brain: Evidence from 5,216 UK Biobank participants (2017, methodology): “Following gradient distortion correction, and further correction for head movement and eddy currents, BEDPOSTx was used to model within-voxel multi-fiber tract orientation, followed by probabilistic tractography (with crossing fiber modeling) using PROBTRACKx (Behrens et al. 2003, 2007; Jbabdi et al”
Multimodal population brain imaging in the UK Biobank prospective epidemiological study (2016, neutral): “The generalised ball & stick model is fit to the multi-shell data, estimating up to 3 crossing fibre orientations per voxel.17, 69 Tractography is then performed in a probabilistic manner to estimate white matter pathways using the voxel-wise orientations.”
Advances in diffusion MRI acquisition and processing in the Human Connectome Project (2013, methodology): “, 2007) and its multi-shell extension (Jbabdi et al., 2012) have been employed for the respective”
Automated quality control for within and between studies diffusion MRI data using a non-parametric framework for movement and distortion correction (2018, neutral): “807 extension of the ball-and-stick model (Behrens et al., 2007; Jbabdi et al., 2012).”
The Human Connectome Project and Beyond: Initial Applications of 300 mT/m Gradients (2013, methodology): “Another potential limitation of the tractography results presented here is that we used the ball and two stick model with DSI data, which has the potential for overfitting and creating false positive tracts (Jbabdi et al., 2012).”
The WU-Minn Human Connectome Project: An Overview (2013, methodology): “HCP has developed novel fiber reconstruction algorithms that are optimized for multi-shell data (Jbabdi et al., 2012).”
The Minimal Preprocessing Pipelines for the Human Connectome Project (2013, positive): “The structural space diffusion data can then be subsequently used for fiber orientation estimation with FSL's multi-shell spherical deconvolution toolbox (bedpostx) (Jbabdi et al., 2012).”
Imaging brain microstructure with diffusion MRI: practicality and applications (2019, methodology): “The heterogeneity is modelled by matrix-valued gamma distributions to generalise the similar approaches in [158, 161-163].”