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Medical-image Analysis and Statistical Interpretation Lab

Stability of Gradient Field Corrections for Quantitative Diffusion MRI

Posted by on Tuesday, November 1, 2016 in Diffusion Tensor Imaging, Diffusion Weighted MRI.

Baxter P. Rogers, Justin Blaber, E. Brian Welch, Zhaohua Ding, Adam W. Anderson, Bennett A. Landman. “Stability of Gradient Field Corrections for Quantitative Diffusion MRI” In Proceedings of the SPIE Medical Imaging Conference. Orlando, Florida, February 2017.

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Abstract

In diffusion-weighted MRI, gradient nonlinearity causes significant bias in the estimation of quantitative diffusion parameters such as diffusivity, anisotropy, and diffusion direction. We measured the gradient stability over time. Over the course of one month the change in these quantities due to calibration-related factors was <0.5% for b-values, and <0.5 degrees for angular deviation. The proposed calibration procedure allows the estimation of gradient nonlinearity to correct b-values and gradient directions ahead of advanced diffusion image processing for high angular resolution data, and requires only a five-minute phantom scan that can be included in a weekly or monthly quality assurance protocol.

Figure 1. LEFT: Image of the gradient field mapping phantom. RIGHT: Measured field map for the X gradient coil. Fields were measured for all three linear gradient coils.

Figure 1. LEFT: Image of the gradient field mapping phantom. RIGHT: Measured field map for the X gradient coil. Fields were measured for all three linear gradient coils.