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Magnetic Resonance Electrical Properties Tomography Based on Modified Physics- Informed Neural Network and Multiconstraints. | LitMetric

AI Article Synopsis

  • This paper introduces a new approach using physics-informed neural networks for magnetic resonance electrical property tomography (MREPT), which is a noninvasive way to assess the electrical properties of tissues during MRI scans.
  • The proposed method aims to overcome issues faced by traditional MREPT methods, like artifacts from simplifying assumptions and errors from numerical differentiation, by applying a model-driven technique based on fully connected neural networks (FCNNs).
  • To improve results, the approach includes additional constraints to ensure the consistency of electrical properties, and it has been tested using realistic simulations and experiments with a high-field animal MRI system.

Article Abstract

This paper presents a novel method based on leveraging physics-informed neural networks for magnetic resonance electrical property tomography (MREPT). MREPT is a noninvasive technique that can retrieve the spatial distribution of electrical properties (EPs) of scanned tissues from measured transmit radiofrequency (RF) in magnetic resonance imaging (MRI) systems. The reconstruction of EP values in MREPT is achieved by solving a partial differential equation derived from Maxwell's equations that lacks a direct solution. Most conventional MREPT methods suffer from artifacts caused by the invalidation of the assumption applied for simplification of the problem and numerical errors caused by numerical differentiation. Existing deep learning-based (DL-based) MREPT methods comprise data-driven methods that need to collect massive datasets for training or model-driven methods that are only validated in trivial cases. Hence we proposed a model-driven method that learns mapping from a measured RF, its spatial gradient and Laplacian to EPs using fully connected networks (FCNNs). The spatial gradient of EP can be computed through the automatic differentiation of FCNNs and the chain rule. FCNNs are optimized using the residual of the central physical equation of convection-reaction MREPT as the loss function ( L) . To alleviate the ill condition of the problem, we added multiconstraints, including the similarity constraint between permittivity and conductivity and the l norm of spatial gradients of permittivity and conductivity, to the L . We demonstrate the proposed method with a three-dimensional realistic head model, a digital phantom simulation, and a practical phantom experiment at a 9.4T animal MRI system.

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Source
http://dx.doi.org/10.1109/TMI.2024.3391651DOI Listing

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