Biomechanics-informed Neural Networks for Myocardial Motion Tracking in MRI

TL;DR

This paper introduces a biomechanics-informed regularisation method using a variational autoencoder to improve myocardial motion tracking in MRI, enhancing accuracy and generalisability by incorporating biomechanical prior knowledge.

Contribution

It presents a novel deep learning regularisation approach that implicitly learns biomechanical priors for more accurate and generalisable myocardial motion tracking in MRI.

Findings

Achieves better motion tracking accuracy than competing methods.

Learns biomechanical properties like incompressibility and strains.

Demonstrates improved generalisability to unseen domains.

Abstract

Image registration is an ill-posed inverse problem which often requires regularisation on the solution space. In contrast to most of the current approaches which impose explicit regularisation terms such as smoothness, in this paper we propose a novel method that can implicitly learn biomechanics-informed regularisation. Such an approach can incorporate application-specific prior knowledge into deep learning based registration. Particularly, the proposed biomechanics-informed regularisation leverages a variational autoencoder (VAE) to learn a manifold for biomechanically plausible deformations and to implicitly capture their underlying properties via reconstructing biomechanical simulations. The learnt VAE regulariser then can be coupled with any deep learning based registration network to regularise the solution space to be biomechanically plausible. The proposed method is validated in the context of myocardial motion tracking on 2D stacks of cardiac MRI data from two different datasets. The results show that it can achieve better performance against other competing methods in terms of motion tracking accuracy and has the ability to learn biomechanical properties such as incompressibility and strains. The method has also been shown to have better generalisability to unseen domains compared with commonly used L2 regularisation schemes.