Bruno Madore1, Jr-Yuan Chiou1, Renxin Chu1, Tzu-Cheng Chao2, Stephan E. Maier1
1Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States; 2Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan, Taiwan
A method is proposed to reduce geometric distortions in diffusion-weighted imaging, at essentially no cost in scan time. The approach exploits the fact that diffusion-encoded data tend to be sparse when represented in the kb-kd space, where kb and kd are the Fourier transform duals of b and d, the b-factor and the diffusion direction, respectively. A main characteristic of the present work is how thoroughly navigator data get utilized in the reconstruction: The phase is used for motion correction, while the magnitude in kb-kd space is used for regularization purposes. Results were obtained showing marked reductions in image distortion as compared to single-shot EPI acquisitions.