Zhangxuan Hu1, Xiaodong Ma1, Trong-Kha Truong2, Allen W Song2, Hua Guo1. 1. Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China. 2. Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina, USA.
Abstract
PURPOSE: Either SENSE+CG or POCS-ICE methods can be used to correct for motion-induced phase errors in navigator-free multishot diffusion imaging. SENSE+CG has the advantage of a fast convergence, however, occasionally the convergence can be unstable, thus degrading the image quality. POCS-ICE has a stable convergence and can be used with a high number of shots, but its convergence is slow, which limits its practical usage. The study here proposes an improved method based on both SENSE+CG and POCS-ICE, called Phase-updated Regularized SENSE (PR-SENSE), for navigator-free multishot diffusion imaging. THEORY AND METHODS: In PR-SENSE, a total variation regularization method is used to solve the SENSE inverse problem instead of the conjugate gradient method used in SENSE+CG. This method is implemented by using a lagged diffusivity fixed point iteration algorithm. Additionally, the phase is updated during the iteration process to improve the image accuracy. RESULTS: Simulations and in vivo experiments demonstrated that PR-SENSE can successfully correct for the motion-induced phase errors in multi-shot DWI. It integrates the advantages of SENSE+CG and POCS-ICE, resulting in a fast and stable convergence with improved image quality. CONCLUSION: Given its advantages, PR-SENSE is a significant improvement over other methods for navigator-free high-resolution DWI. Magn Reson Med 78:172-181, 2017.
PURPOSE: Either SENSE+CG or POCS-ICE methods can be used to correct for motion-induced phase errors in navigator-free multishot diffusion imaging. SENSE+CG has the advantage of a fast convergence, however, occasionally the convergence can be unstable, thus degrading the image quality. POCS-ICE has a stable convergence and can be used with a high number of shots, but its convergence is slow, which limits its practical usage. The study here proposes an improved method based on both SENSE+CG and POCS-ICE, called Phase-updated Regularized SENSE (PR-SENSE), for navigator-free multishot diffusion imaging. THEORY AND METHODS: In PR-SENSE, a total variation regularization method is used to solve the SENSE inverse problem instead of the conjugate gradient method used in SENSE+CG. This method is implemented by using a lagged diffusivity fixed point iteration algorithm. Additionally, the phase is updated during the iteration process to improve the image accuracy. RESULTS: Simulations and in vivo experiments demonstrated that PR-SENSE can successfully correct for the motion-induced phase errors in multi-shot DWI. It integrates the advantages of SENSE+CG and POCS-ICE, resulting in a fast and stable convergence with improved image quality. CONCLUSION: Given its advantages, PR-SENSE is a significant improvement over other methods for navigator-free high-resolution DWI. Magn Reson Med 78:172-181, 2017.
Authors: Congyu Liao; Jason Stockmann; Qiyuan Tian; Berkin Bilgic; Nicolas S Arango; Mary Kate Manhard; Susie Y Huang; William A Grissom; Lawrence L Wald; Kawin Setsompop Journal: Magn Reson Med Date: 2019-08-01 Impact factor: 4.668
Authors: Yuxin Hu; Evan G Levine; Qiyuan Tian; Catherine J Moran; Xiaole Wang; Valentina Taviani; Shreyas S Vasanawala; Jennifer A McNab; Bruce A Daniel; Brian L Hargreaves Journal: Magn Reson Med Date: 2018-10-22 Impact factor: 4.668