PURPOSE: Quantitative susceptibility map (QSM) reconstruction is ill posed due to the zero values on the "magic angle cone" that make the maps prone to streaking artifacts. We propose projection onto convex sets (POCS) in the method of steepest descent (SD) for QSM reconstruction. METHODS: Two convex projections, an object-support projection in the image domain and a projection in k-space were used. QSM reconstruction using the proposed SD-POCS method was compared with SD and POCS alone as well as with truncated k-space division (TKD) for numerically simulated and 7 Tesla (T) human brain phase data. RESULTS: The QSM reconstruction error from noise-free simulated phase data using SD-POCS is at least two orders of magnitude lower than using SD, POCS, or TKD and has reduced streaking artifacts. Using the l1 -TV reconstructed susceptibility as a gold standard for 7T in vivo imaging, SD-POCS showed better image quality comparing to SD, POCS, or TKD from visual inspection. CONCLUSION: POCS is an alternative method for regularization that can be used in an iterative minimization method such as SD for QSM reconstruction.
PURPOSE: Quantitative susceptibility map (QSM) reconstruction is ill posed due to the zero values on the "magic angle cone" that make the maps prone to streaking artifacts. We propose projection onto convex sets (POCS) in the method of steepest descent (SD) for QSM reconstruction. METHODS: Two convex projections, an object-support projection in the image domain and a projection in k-space were used. QSM reconstruction using the proposed SD-POCS method was compared with SD and POCS alone as well as with truncated k-space division (TKD) for numerically simulated and 7 Tesla (T) human brain phase data. RESULTS: The QSM reconstruction error from noise-free simulated phase data using SD-POCS is at least two orders of magnitude lower than using SD, POCS, or TKD and has reduced streaking artifacts. Using the l1 -TV reconstructed susceptibility as a gold standard for 7T in vivo imaging, SD-POCS showed better image quality comparing to SD, POCS, or TKD from visual inspection. CONCLUSION: POCS is an alternative method for regularization that can be used in an iterative minimization method such as SD for QSM reconstruction.
Authors: Stephen M Smith; Mark Jenkinson; Mark W Woolrich; Christian F Beckmann; Timothy E J Behrens; Heidi Johansen-Berg; Peter R Bannister; Marilena De Luca; Ivana Drobnjak; David E Flitney; Rami K Niazy; James Saunders; John Vickers; Yongyue Zhang; Nicola De Stefano; J Michael Brady; Paul M Matthews Journal: Neuroimage Date: 2004 Impact factor: 6.556
Authors: G Bartzokis; J L Cummings; C H Markham; P Z Marmarelis; L J Treciokas; T A Tishler; S R Marder; J Mintz Journal: Magn Reson Imaging Date: 1999-02 Impact factor: 2.546
Authors: Tian Liu; Ildar Khalidov; Ludovic de Rochefort; Pascal Spincemaille; Jing Liu; A John Tsiouris; Yi Wang Journal: NMR Biomed Date: 2011-03-08 Impact factor: 4.044
Authors: Carlos Milovic; Cristian Tejos; Julio Acosta-Cabronero; Pinar Senay Özbay; Ferdinand Schwesser; Jose Pedro Marques; Pablo Irarrazaval; Berkin Bilgic; Christian Langkammer Journal: Magn Reson Med Date: 2020-02-21 Impact factor: 4.668