Martin Blaimer1, Andr Fischer1, Philipp Ehses2, Nicole Seiberlich3, Mark A. Griswold3, Peter M. Jakob1,2, Felix A. Breuer1
1Research Center Magnetic Resonance Bavaria (MRB), Wrzburg, Bavaria, Germany; 2Department of Experimental Physics 5, University of Wrzburg, Wrzburg, Bavaria, Germany; 3Department of Radiology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH, USA
Generalized solutions for parallel MRI using arbitrary k-space trajectories are mainly based on iterative algorithms, such as conjugate gradient SENSE. In addition, an iterative GRAPPA approach for arbitrary k-space sampling has been presented. However, the reconstruction process includes several steps, including gridding, GRAPPA convolution and re-sampling operations during each iteration. Here, we present a simplified iterative GRAPPA algorithm. The key element is a GRAPPA-operator gridding (GROG) step prior to the iteration loop which removes the need for gridding and resampling during each iteration. This allows a robust and computationally efficient reconstruction of accelerated non-Cartesian MRI experiments.