Improved Image Reconstruction and Diffusion Parameter Estimation Using a Temporal Convolutional Network Model of Gradient Trajectory Errors

TL;DR

This paper introduces a temporal convolutional network that accurately models gradient trajectory errors in MRI, leading to improved image reconstruction and diffusion parameter estimation by correcting nonlinear gradient distortions.

Contribution

The study presents a novel nonlinear gradient system model using convolutional networks, outperforming linear methods in predicting gradient distortions in MRI.

Findings

Accurately predicts nonlinear gradient distortions

Improves image quality and diffusion mapping

Outperforms existing linear correction methods

Abstract

Summary: Errors in gradient trajectories introduce significant artifacts and distortions in magnetic resonance images, particularly in non-Cartesian imaging sequences, where imperfect gradient waveforms can greatly reduce image quality. Purpose: Our objective is to develop a general, nonlinear gradient system model that can accurately predict gradient distortions using convolutional networks. Methods: A set of training gradient waveforms were measured on a small animal imaging system, and used to train a temporal convolutional network to predict the gradient waveforms produced by the imaging system. Results: The trained network was able to accurately predict nonlinear distortions produced by the gradient system. Network prediction of gradient waveforms was incorporated into the image reconstruction pipeline and provided improvements in image quality and diffusion parameter mapping compared to both the nominal gradient waveform and the gradient impulse response function. Conclusion: Temporal convolutional networks can more accurately model gradient system behavior than existing linear methods and may be used to retrospectively correct gradient errors.