Motion-compensated cardiac MRI using low-rank diffeomorphic flow (DMoCo)

We introduce an unsupervised motion-compensated image reconstruction algorithm for free-breathing and ungated 3D cardiac magnetic resonance imaging (MRI). We express the image volume corresponding to each specific motion phase as the deformation of a single static image template. The main contribution of the work is the low-rank model for the compact joint representation of the family of diffeomorphisms, parameterized by the motion phases. The diffeomorphism at a specific motion phase is obtained by integrating a parametric velocity field along a path connecting the reference template phase to the motion phase. The velocity field at different phases is represented using a low-rank model. The static template and the low-rank motion model parameters are learned directly from the k-space data in an unsupervised fashion. The more constrained motion model is observed to offer improved recovery compared to current motion-resolved and motion-compensated algorithms for free-breathing 3D cine MRI.

@article{kettelkamp2025_2505.03149,
  title={ Motion-compensated cardiac MRI using low-rank diffeomorphic flow (DMoCo) },
  author={ Joseph Kettelkamp and Ludovica Romanin and Sarv Priya and Mathews Jacob },
  journal={arXiv preprint arXiv:2505.03149},
  year={ 2025 }
}