3D Residual Eddy Current Field Characterisation: applied to Diffusion Weighted Magnetic Resonance Imaging
Clinical use of the Stejskal-Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3D eddy current field induced. In this work we aimed to predict, using linear response theory, the residual 3D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to 1Hz. The model’s performance was tested on diffusion weighted images of 4 normal volunteers, following distortion correction, the image quality of the Stejskal-Tanner diffusion-weighted images was found to have comparable image quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3D eddy current field with linear response theory enables the prediction of the 3D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.