1Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany3Section on Experimental Radiology, University of Tübingen, Tübingen, Germany4Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
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Purpose:To enable fast and flexible high-resolution four-dimensional (4D) MRI of periodic thoracic/abdominal motion for motion visualization or motion-corrected imaging.Methods:We proposed a Cartesian three-dimensional k-space sampling scheme that acquires a random combination of k-space lines in the Symbol plane. A partial Fourier–like constraint compacts the sampling space to one half of k-space. The central k-space line is periodically acquired to allow an extraction of a self-navigated respiration signal used to populate a k-space of multiple breathing positions. The randomness of the acquisition (induced by periodic breathing pattern) yields a subsampled k-space that is reconstructed using compressed sensing. Local image evaluations (coefficient of variation and slope steepness through organs) reveal information about motion resolvability. Image quality is inspected by a blinded reading. Sequence and reconstruction method are made publicly available.Results:The method is able to capture and reconstruct 4D images with high image quality and motion resolution within a short scan time of less than 2 min. These findings are supported by restricted-isometry-property analysis, local image evaluation, and blinded reading.Conclusion:The proposed method provides a clinical feasible setup to capture periodic respiratory motion with a fast acquisition protocol and can be extended by further surrogate signals to capture additional periodic motions. Retrospective parametrization allows for flexible tuning toward the targeted applications.