Accelerating dynamic spiral MRI by algebraic reconstruction from undersampled k-t space
Nielsen J, Shin T, Nayak K
University of Southern California
The temporal resolution of dynamic MRI can be increased by sampling a fraction of k-space in an interleaved fashion, which causes spatial and temporal aliasing. We describe algebraically and graphically the aliasing process in dynamic spiral imaging to formulate unaliasing as a set of inverse problems. Since each linear system is numerically rank deficient, zero assumption in the solution and regularization are proposed. To reduce required memory and computation time, conjugate gradient method is employed as an iterative linear solver. In-vivo experiments using real-time spiral cardiac imaging demonstrate improved temporal resolution of the proposed method.