title: Flow-suppressed hyperpolarized13C chemical shift imaging using velocity-optimized bipolar gradient in mouse liver tumors at 9.4 T.
abstract: To optimize and investigate the influence of bipolar gradients for flow suppression in metabolic quantification of hyperpolarized13C chemical shift imaging (CSI) of mouse liver at 9.4 T.
  
  
  
  The trade-off between the amount of flow suppression using bipolar gradients and T2* effect from static spins was simulated. A free induction decay CSI sequence with alternations between the flow-suppressed and non-flow-suppressed acquisitions for each repetition time was developed and was applied to liver tumor-bearing mice via injection of hyperpolarized [1-13C] pyruvate.
  
  
  
  The in vivo results from flow suppression using the velocity-optimized bipolar gradient were comparable with the simulation results. The vascular signal was adequately suppressed and signal loss in stationary tissue was minimized. Application of the velocity-optimized bipolar gradient to tumor-bearing mice showed reduction in the vessel-derived pyruvate signal contamination, and the average lactate/pyruvate ratio increased by 0.095 (P < 0.05) in the tumor region after flow suppression.
  
  
  
  Optimization of the bipolar gradient is essential because of the short13C T2* and high signal in venous flow in the mouse liver. The proposed velocity-optimized bipolar gradient can suppress the vascular signal, minimizing T2*-related signal loss in stationary tissues at 9.4 T. Magn Reson Med 78:1674-1682, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Hansol
authors.initials: H
authors.lastname: Lee
authors.affiliation: Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea.
authors.forename: Joonsung
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Eunhae
authors.initials: E
authors.lastname: Joe
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Seungwook
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Song
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Young-Suk
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Eunkyung
authors.initials: E
authors.lastname: Wang
authors.affiliation: Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Chan Gyu
authors.initials: CG
authors.lastname: Joo
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Ho-Taek
authors.initials: HT
authors.lastname: Song
authors.affiliation: Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea.
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000097:blood / Q000378:metabolism*; D005260:Female; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D019047:Phantoms, Imaging
chemical_list: D002247:Carbon Isotopes
keywords: bipolar gradient; flow suppression; hyperpolarized 13C; liver tumor; pyruvate; slow venous flow