title: Robust water fat separated dual-echo MRI by phase-sensitive reconstruction.
abstract: The purpose of this work was to develop and evaluate a robust water-fat separation method for T1-weighted symmetric two-point Dixon data.
  
  
  
  A method for water-fat separation by phase unwrapping of the opposite-phase images by phase-sensitive reconstruction (PSR) is introduced. PSR consists of three steps; (1), identification of clusters of tissue voxels; (2), unwrapping of the phase in each cluster by solving Poisson's equation; and (3), finding the correct sign of each unwrapped opposite-phase cluster, so that the water-fat images are assigned the correct identities. Robustness was evaluated by counting the number of water-fat swap artifacts in a total of 733 image volumes. The method was also compared to commercial software.
  
  
  
  In the water-fat separated image volumes, the PSR method failed to unwrap the phase of one cluster and misclassified 10. One swap was observed in areas affected by motion and was constricted to the affected area. Twenty swaps were observed surrounding susceptibility artifacts, none of which spread outside the artifact affected regions. The PSR method had fewer swaps when compared to commercial software.
  
  
  
  The PSR method can robustly produce water-fat separated whole-body images based on symmetric two-echo spoiled gradient echo images, under both ideal conditions and in the presence of common artifacts. Magn Reson Med 78:1208-1216, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors: Department of Biomedical Engineering, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
authors: Thobias
authors: T
authors: Romu
authors: Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.|Department of Radiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors: Nils
authors: N
authors: Dahlström
authors: Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.|Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors: Olof Dahlqvist
authors: OD
authors: Leinhard
authors: Department of Biomedical Engineering, Linköping University, Linköping, Sweden.|Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
authors: Magnus
authors: M
authors: Borga
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry / Q000000981:diagnostic imaging*; D000465:Algorithms; D001834:Body Water / Q000737:chemistry / Q000000981:diagnostic imaging*; D005223:Fats / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051598:Whole Body Imaging
chemical_list: D005223:Fats
keywords: Dixon imaging; phase correction; segmentation; water-fat separation; whole-body imaging