Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Magn Reson Med. 2018 Jul;80(1):11-20. doi: 10.1002/mrm.27003. Epub 2017 Nov 13.
C magnetic resonance spectroscopy (MRS) in combination with infusion of C-labeled substrates has led to unique insights into human brain metabolism and neurotransmitter cycling. However, the low sensitivity of direct C MRS and high radiofrequency power requirements has limited C MRS studies to predominantly data acquisition in large volumes of the occipital cortex. The purpose of this study is to develop an MRS technique for localized detection of C-labeling of glutamate and glutamine in the human frontal lobe.
We used an indirect ( H-[ C]), proton-observed, carbon-edited MRS sequence (selPOCE) for detection of C-labeled metabolites in relatively small volumes located in the frontal lobe at 4 T. The SelPOCE method allows for selective and separate detection of glutamate and glutamine resonances, which significantly overlap at magnetic field strengths used for clinical MRI.
Phantom data illustrate how selPOCE can be tuned to selectively detect C labeling in different metabolites. Three-dimensional specific absorption rate simulations of radiofrequency power deposition show that the selPOCE method operates comfortably within the global and local Food and Drug Administration specific absorption rate guidelines. In vivo selPOCE data are presented, which were acquired from a 45-mL volume in the frontal lobe of healthy subjects. The in vivo data show the time-dependent C-labeling of glutamate and glutamine during intravenous infusion of [1- C]-glucose. Metrics describing spectral fitting quality of the glutamate and glutamine resonances are reported.
The SelPOCE sequence allows the detection of C-labeling in glutamate and glutamine from a relatively small volume in the human frontal lobe at low radiofrequency power requirements. Magn Reson Med 80:11-20, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
C 磁共振波谱（MRS）与 C 标记底物的输注相结合，使人们对人类大脑代谢和神经递质循环有了独特的认识。然而，直接 C MRS 的低灵敏度和高射频功率要求限制了 C MRS 研究主要在枕叶的大体积数据采集。本研究旨在开发一种用于局部检测谷氨酸和谷氨酰胺在人额叶中 13 C 标记的 MRS 技术。
我们使用间接（H-[13C]）、质子观察、碳编辑的 MRS 序列（selPOCE），在 4T 下检测额叶内相对较小体积中 13 C 标记代谢物。SelPOCE 方法允许选择性和单独检测谷氨酸和谷氨酰胺共振，这些共振在用于临床 MRI 的磁场强度下显著重叠。
幻影数据说明了 selPOCE 如何能够调谐以选择性地检测不同代谢物中的 13 C 标记。射频功率沉积的三维特定吸收率模拟表明，selPOCE 方法在全球和局部食品和药物管理局特定吸收率指南内舒适地运行。呈现了来自健康受试者额叶中 45ml 体积的体内 selPOCE 数据。体内数据显示了静脉内输注[1-13C]-葡萄糖期间谷氨酸和谷氨酰胺的时间依赖性 13 C 标记。报告了描述谷氨酸和谷氨酰胺共振光谱拟合质量的度量。
SelPOCE 序列允许在低射频功率要求下从人额叶的相对较小体积中检测谷氨酸和谷氨酰胺的 13 C 标记。磁共振医学 80:11-20,2018。©2017 年国际磁共振学会。
