title: Phase-updated regularized SENSE for navigator-free multishot diffusion imaging.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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. © 2016 International Society for Magnetic Resonance in Medicine.
authors: Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors: Zhangxuan
authors: Z
authors: Hu
authors: Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors: Xiaodong
authors: X
authors: Ma
authors: Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina, USA.
authors: Trong-Kha
authors: TK
authors: Truong
authors: Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina, USA.
authors: Allen W
authors: AW
authors: Song
authors: Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors: Hua
authors: H
authors: Guo
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: POCS-ICE; PR-SENSE; SENSE+CG; diffusion-weighted imaging (DWI); multishot diffusion imaging; phase correction