Purpose: To optimize and investigate the influence of bipolar gradients for flow suppression in metabolic quantification of hyperpolarized 13C chemical shift imaging (CSI) of mouse liver at 9.4 T. Methods: 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. Results: 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. Conclusion: Optimization of the bipolar gradient is essential because of the short 13C 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.
Bibliographical noteFunding Information:
1Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea. 2Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea. 3Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea. 4Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea. Grant sponsor: Korean Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), Ministry for Health, Welfare & Family Affairs, Republic of Korea; Grant number: HI15C2422. *Correspondence to: Dong-Hyun Kim, Ph.D., Department of Electrical and Electronic Engineering, Building Number 124, Room C228, Yonsei University, Seoul 120-749, Korea. E-mail: email@example.com This study was presented in part at the Annual Meeting of the World Molecular Imaging Congress, Honolulu, Hawaii, USA, 2015. Received 15 July 2016; revised 21 November 2016; accepted 21 November 2016 DOI 10.1002/mrm.26578 Published online 26 December 2016 in Wiley Online Library (wileyonlinelibrary.com).
All Science Journal Classification (ASJC) codes
- Radiology Nuclear Medicine and imaging