Time-Dependent Deep Image Prior for Dynamic MRI

TL;DR

This paper introduces a novel unsupervised deep learning method for dynamic MRI reconstruction that does not require training data, effectively capturing continuous temporal variations in high-resolution images.

Contribution

It presents a generalized deep-image-prior approach for dynamic MRI that encodes temporal variations without prior training or additional data, outperforming existing methods.

Findings

Outperforms state-of-the-art methods quantitatively and qualitatively

Does not require heartbeat marking or spoke reordering for cardiac images

Successfully reconstructs continuous dynamic MRI sequences with high spatial resolution

Abstract

We propose a novel unsupervised deep-learning-based algorithm for dynamic magnetic resonance imaging (MRI) reconstruction. Dynamic MRI requires rapid data acquisition for the study of moving organs such as the heart. Existing reconstruction methods suffer from restrictions either in the model design or in the absence of ground-truth data, resulting in low image quality. We introduce a generalized version of the deep-image-prior approach, which optimizes the network weights to fit a sequence of sparsely acquired dynamic MRI measurements. Our method needs neither prior training nor additional data. In particular, for cardiac images, it does not require the marking of heartbeats or the reordering of spokes. The key ingredients of our method are threefold: 1) a fixed low-dimensional manifold that encodes the temporal variations of images; 2) a network that maps the manifold into a more expressive latent space; and 3) a convolutional neural network that generates a dynamic series of MRI images from the latent variables and that favors their consistency with the measurements in k-space. Our method outperforms the state-of-the-art methods quantitatively and qualitatively in both retrospective and real fetal cardiac datasets. To the best of our knowledge, this is the first unsupervised deep-learning-based method that can reconstruct the continuous variation of dynamic MRI sequences with high spatial resolution.