应用 13C-1 标记的葡萄糖后人体脑部肿瘤的活体 13C 磁共振波谱分析

In vivo 13C magnetic resonance spectroscopy of a human brain tumor after application of 13C-1-enriched glucose.

机构信息

Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.

出版信息

Magn Reson Imaging. 2010 Jun;28(5):690-7. doi: 10.1016/j.mri.2010.03.006.

DOI:10.1016/j.mri.2010.03.006

PMID:20399584

Abstract

OBJECTIVES

As a unique tool to assess metabolic fluxes noninvasively, (13)C magnetic resonance spectroscopy (MRS) could help to characterize and understand malignancy in human tumors. However, its low sensitivity has hampered applications in patients. The aim of this study was to demonstrate that with sensitivity-optimized localized (13)C MRS and intravenous infusion of [1-(13)C]glucose under euglycemia, it is possible to assess the dynamic conversion of glucose into its metabolic products in vivo in human glioma tissue.

MATERIALS AND METHODS

Measurements were done at 3 T with a broadband single RF channel and a quadrature (13)C surface coil inserted in a (1)H volume coil. A (1)H/(13)C polarization transfer sequence was applied, modified for localized acquisition, alternatively in two (50 ml) voxels, one encompassing the tumor and the other normal brain tissue.

RESULTS

After about 20 min of [1-(13)C]glucose infusion, a [3-(13)C]lactate signal appeared among several resonances of metabolic products of glucose in MR spectra of the tumor voxel. The resonance of [3-(13)C]lactate was absent in MR spectra from contralateral tissue. In addition, the intensity of [1-(13)C]glucose signals in the tumor area was about 50% higher than that in normal tissue, likely reflecting more glucose in extracellular space due to a defective blood-brain barrier. The signal intensity for metabolites produced in or via the tricarboxylic acid (TCA) cycle was lower in the tumor than in the contralateral area, albeit that the ratios of isotopomer signals were comparable.

CONCLUSION

With an improved (13)C MRS approach, the uptake of glucose and its conversion into metabolites such as lactate can be monitored noninvasively in vivo in human brain tumors. This opens the way to assessing metabolic activity in human tumor tissue.

摘要

目的

作为一种无创评估代谢通量的独特工具，（13）C 磁共振波谱（MRS）可以帮助对人类肿瘤的恶性特征进行定性和了解。然而，其低灵敏度限制了其在患者中的应用。本研究旨在证明，通过优化灵敏度的局部（13）C MRS 和静脉输注[1-（13）C]葡萄糖以保持血糖正常，可以在人体胶质瘤组织中体内评估葡萄糖转化为其代谢产物的动态过程。

材料和方法

在 3 T 下使用宽带单射频通道和正交（13）C 表面线圈进行测量，该线圈插入（1）H 体线圈中。应用（1）H/（13）C 极化转移序列，对局部采集进行修改，分别在两个（50 ml）体素中交替应用，一个体素包括肿瘤，另一个体素包括正常脑组织。

结果

在[1-（13）C]葡萄糖输注约 20 分钟后，在肿瘤体素的 MR 谱中，葡萄糖代谢产物的多个共振中出现了[3-（13）C]乳酸共振。对侧组织的 MR 谱中不存在[3-（13）C]乳酸共振。此外，肿瘤区域[1-（13）C]葡萄糖信号的强度比正常组织高约 50％，这可能反映了由于血脑屏障缺陷导致细胞外空间中有更多的葡萄糖。尽管各同位素峰信号的比值相当，但 TCA 循环中或通过 TCA 循环生成的代谢产物的信号强度在肿瘤中比在对侧区域中低。