Physics-informed neural networks for myocardial perfusion MRI quantification

TL;DR

This paper introduces physics-informed neural networks (PINNs) for myocardial perfusion MRI quantification, improving parameter estimation accuracy by integrating physical models with neural networks, validated through simulations and patient data.

Contribution

The study presents a novel PINN framework for myocardial perfusion MRI analysis, combining physical laws with neural networks to enhance parameter inference accuracy.

Findings

Reduced mean-squared error in simulations compared to traditional methods

Parameter maps align with clinical diagnoses

Method produces physiologically plausible parameter estimates

Abstract

Tracer-kinetic models allow for the quantification of kinetic parameters such as blood flow from dynamic contrast-enhanced magnetic resonance (MR) images. Fitting the observed data with multi-compartment exchange models is desirable, as they are physiologically plausible and resolve directly for blood flow and microvascular function. However, the reliability of model fitting is limited by the low signal-to-noise ratio, temporal resolution, and acquisition length. This may result in inaccurate parameter estimates. This study introduces physics-informed neural networks (PINNs) as a means to perform myocardial perfusion MR quantification, which provides a versatile scheme for the inference of kinetic parameters. These neural networks can be trained to fit the observed perfusion MR data while respecting the underlying physical conservation laws described by a multi-compartment exchange model. Here, we provide a framework for the implementation of PINNs in myocardial perfusion MR. The approach is validated both in silico and in vivo. In the in silico study, an overall reduction in mean-squared error with the ground-truth parameters was observed compared to a standard non-linear least squares fitting approach. The in vivo study demonstrates that the method produces parameter values comparable to those previously found in literature, as well as providing parameter maps which match the clinical diagnosis of patients.