1. Free-Breathing and Ungated Dynamic MRI Using Navigator-Less Spiral SToRM.
- Author
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Ahmed, Abdul Haseeb, Zhou, Ruixi, Yang, Yang, Nagpal, Prashant, Salerno, Michael, and Jacob, Mathews
- Subjects
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LOW-rank matrices , *K-spaces , *MISSING data (Statistics) , *FOUR-dimensional imaging , *RESPIRATION , *SPIRAL computed tomography , *ALGORITHMS , *EXPLORERS - Abstract
We introduce a kernel low-rank algorithm to recover free-breathing and ungated dynamic MRI from spiral acquisitions without explicit k-space navigators. It is often challenging for low-rank methods to recover free-breathing and ungated images from undersampled measurements; extensive cardiac and respiratory motion often results in the Casorati matrix not being sufficiently low-rank. Therefore, we exploit the non-linear structure of the dynamic data, which gives the low-rank kernel matrix. Unlike prior work that rely on navigators to estimate the manifold structure, we propose a kernel low-rank matrix completion method to directly fill in the missing k-space data from variable density spiral acquisitions. We validate the proposed scheme using simulated data and in-vivo data. Our results show that the proposed scheme provides improved reconstructions compared to the classical methods such as low-rank and XD-GRASP. The comparison with breath-held cine data shows that the quantitative metrics agree, whereas the image quality is marginally lower. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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