3D FRONSAC with PSF reconstruction

TL;DR

This paper extends the FRONSAC method to 3D MRI acquisitions, demonstrating that 3D FRONSAC improves image quality in undersampled reconstructions without altering contrast, making 3D imaging more practical.

Contribution

It introduces the first 3D FRONSAC implementation and a transform domain reconstruction, enhancing parallel imaging performance and undersampled image quality.

Findings

3D FRONSAC is feasible for human MRI scans.

FRONSAC reduces undersampling artifacts and ghosts.

Image quality metrics like SSIM and NRMSE improve with FRONSAC.

Abstract

Purpose: This study extends the Fast ROtary Nonlinear Spatial ACquisition (FRONSAC) method to include 3D acquisitions and reconstructions. It also presents a transform domain reconstruction that makes 3D reconstructions practical and provides new insights into how parallel imaging performance is enhanced by FRONSAC encoding. Methods: This work developed the first examples of FRONSAC incorporated into a 3D acquisition. 3D FRONSAC was tested on human subjects with both simple gradient echo and MPRAGE Cartesian acquisitions. The quality of the 3D FRONSAC images was evaluated using structural similarity index measure (SSIM), and normalized root mean square error (NRMSE). Results: FRONSAC encoding did not significantly modify the contrast obtained in either sequence, but it substantially improves the image quality of undersampled reconstruction. FRONSAC images have reduced undersampling ghosts and consistently improved SSIM and NRMSE. Conclusions: Acquisition and reconstruction of 3D FRONSAC images are feasible, and the additional FRONSAC encoding improves image quality in highly undersampled images.