Stefan Kroboth1, Frederik Testud2, Kristian Bredies3, Kelvin J. Layton4, Daniel Gallichan5, Chris A. Cocosco2, Gerrit Schultz2, Florian Knoll1, Christoph Barmet6, 7, Klaas P. Pruessmann8, Maxim Zaitsev2, Rudolf Stollberger1
1Institute of Medical Engineering, Graz University of Technology, Graz, Austria; 2Medical Physics, University Medical Center Freiburg, Freiburg, Germany; 3Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria; 4Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, Victoria, Australia; 5LIFMET, Ecole Polytchnique Fdrale de Lausanne, Lausanne, Switzerland; 6Institute for Biomedical Engineering, University and ETH Zurich, Zrich, Switzerland; 7Skope Magnetic Resonance Technologies, Zrich, Switzerland; 8Institute for Biomedical Engineering, University of Zrich and ETH Zrich, Zrich, Switzerland
This work investigates the reconstruction of single shot North-West Echo Planar Imaging (NW-EPI) data with estimated trajectories using field cameras. NW-EPI is a multidimensional trajectory designed to improve the resolution in a selected region by exploiting the spatially varying resolution characteristic of nonlinear PatLoc fields. Reconstruction with Total Generalized Variation (TGV) was successfully applied to PatLoc imaging with 2D trajectories to reduce noise, Gibbs ringing and undersampling artifacts. However, for multidimensional trajectories, TGV converges very slowly. We therefore present a new concept of numerically solving the inverse problem, called Total Generalized Variation - Conjugate Gradient (TGV-CG) to increase convergence speed.