A comparative simulation study of bayesian fitting approaches to intravoxel incoherent motion modeling in diffusion-weighted MRI.
PURPOSE
To assess the performance of various least squares and Bayesian modeling approaches to parameter estimation in intravoxel incoherent motion (IVIM) modeling of diffusion-weighted MRI data.


METHODS
Simulated tissue models of different type (breast/liver) and morphology (discrete/continuous) were used to generate noisy data according to the IVIM model at several signal-to-noise ratios. IVIM parameter maps were generated using six different approaches, including full nonlinear least squares (LSQ), segmented least squares (SEG), Bayesian modeling with a Gaussian shrinkage prior (BSP) and Bayesian modeling with a spatial homogeneity prior (FBM), plus two modified approaches. Estimators were compared by calculating the median absolute percentage error and deviation, and median percentage bias.


RESULTS
The Bayesian modeling approaches consistently outperformed the least squares approaches, with lower relative error and deviation, and provided cleaner parameter maps with reduced erroneous heterogeneity. However, a weakness of the Bayesian approaches was exposed, whereby certain tissue features disappeared completely in regions of high parameter uncertainty. Lower error and deviation were generally afforded by FBM compared with BSP, at the cost of higher bias.


CONCLUSIONS
Bayesian modeling is capable of producing more visually pleasing IVIM parameter maps than least squares approaches, but their potential to mask certain tissue features demands caution during implementation. Magn Reson Med 78:2373-2387, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
['While|Peter T|PT|']
D000328:Adult D000465:Algorithms D016477:Artifacts D001499:Bayes Theorem D001940:Breast D003198:Computer Simulation D038524:Diffusion Magnetic Resonance Imaging D005260:Female D006801:Humans D007089:Image Enhancement D007091:Image Processing, Computer-Assisted D016018:Least-Squares Analysis D008099:Liver D008297:Male D009038:Motion D016011:Normal Distribution D015203:Reproducibility of Results D059629:Signal-To-Noise Ratio
intravoxel incoherent motion least squares Bayesian analysis diffusion MRI estimation techniques