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Medical-image Analysis and Statistical Interpretation Lab

Assessment of bias for MRI diffusion tensor imaging using SIMEX

Posted by on Friday, September 30, 2011 in Diffusion Weighted MRI.

Carolyn B. Lauzon, Andrew Asman, Ciprian Crainiceanu, Brian Caffo, Bennett A. Landman. “Assessment of Bias for MRI Diffusion Tensor Imaging Using SIMEX”, In International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI), Toronto, Canada, September 2011 (30% acceptance rate) NIHMS ID 301343

Full text: https://www.ncbi.nlm.nih.gov/pubmed/21995019

Abstract

Diffusion Tensor Imaging (DTI) is a Magnetic Resonance Imaging method for measuring water diffusion in vivo. One powerful DTI contrast is fractional anisotropy (FA). FA reflects the strength of water’s diffusion directional preference and is a primary metric for neuronal fiber tracking. As with other DTI contrasts, FA measurements are obscured by the well established presence of bias. DTI bias has been challenging to assess because it is a multivariable problem including SNR, six tensor parameters, and the DTI collection and processing method used. SIMEX is a modem statistical technique that estimates bias by tracking measurement error as a function of added noise. Here, we use SIMEX to assess bias in FA measurements and show the method provides; i) accurate FA bias estimates, ii) representation of FA bias that is data set specific and accessible to non-statisticians, and iii) a first time possibility for incorporation of bias into DTI data analysis.

Flow chart of steps to create SIMEX Estimated Bias and True Bias maps. Variables refer to terms defined explicitly by equations in the Theory section.
Flow chart of steps to create SIMEX Estimated Bias and True Bias maps. Variables refer to terms defined explicitly by equations in the Theory section.

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