Flow-Suppressed Hyperpolarized 13C Chemical Shift Imaging Using Velocity-Optimized Bipolar Gradient in Mouse Liver Tumors at 9.4 T
Flow-Suppressed Hyperpolarized 13C Chemical Shift Imaging Using Velocity-Optimized Bipolar Gradient in Mouse Liver Tumors at 9.4 T
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DOI：
10.1002/mrm.26578
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发表时间：
2017-11-01
影响因子：
3.3
通讯作者：
Kim, Dong-Hyun
中科院分区：
文献类型：
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作者：
Lee, Hansol;Lee, Joonsung;Kim, Dong-Hyun
目的：优化并研究双极梯度对流动抑制在 9.4 T 小鼠肝脏超极化 C-13 化学位移成像 (CSI) 代谢定量中的影响。方法：模拟双极梯度流动抑制量与静态自旋 T-2* 效应之间的权衡。开发了一种自由感应衰减 CSI 序列，每次重复时间在流量抑制和非流量抑制采集之间交替，并通过注射超极化的 [1-C-13] 丙酮酸盐应用于肝肿瘤小鼠。 结果：使用速度优化双极梯度的流量抑制的体内结果与模拟结果相当。血管信号被充分抑制，静止组织中的信号损失被最小化。将速度优化的双极梯度应用于荷瘤小鼠后，血管来源的丙酮酸信号污染减少，并且在血流抑制后，肿瘤区域的平均乳酸/丙酮酸比值增加了 0.095 (P < 0.05)。结论：由于小鼠肝脏中的 C-13 T-2* 较短和静脉血流信号较高，双极梯度的优化至关重要。所提出的速度优化双极梯度可以抑制血管信号，最大限度地减少 9.4 T 下静止组织中 T-2* 相关的信号丢失。(C) 2016 国际医学磁共振学会。
Purpose: To optimize and investigate the influence of bipolar gradients for flow suppression in metabolic quantification of hyperpolarized C-13 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 T-2* effect from static spins was simulated. A free induction decay CSI sequence with alternations between the flow-suppressed and non-flowsuppressed acquisitions for each repetition time was developed and was applied to liver tumor-bearing mice via injection of hyperpolarized [1-C-13] 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 tumorbearing 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 C-13 T-2* and high signal in venous flow in the mouse liver. The proposed velocity-optimized bipolar gradient can suppress the vascular signal, minimizing T-2*-related signal loss in stationary tissues at 9.4 T. (C) 2016 International Society for Magnetic Resonance in Medicine.