Noninvasive mapping of spontaneous fluctuations in tumor oxygenation using 19F MRI
Noninvasive mapping of spontaneous fluctuations in tumor oxygenation using 19F MRI
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DOI：
10.1118/1.3484056
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发表时间：
2010-10-01
期刊：
影响因子：
3.8
通讯作者：
Gallez, B.
中科院分区：
文献类型：
--
作者：
Magat, J.;Jordan, B. F.;Gallez, B.
目的：已知急性缺氧（缺氧-复氧的短暂循环）发生在实体瘤中，并且可能是一个认识不足的治疗问题，因为它可能与对放射治疗的抗性、化疗剂的递送受损或转移发展有关。本研究的目的是使用MR F-19弛豫图来分析实验性肿瘤中氧分压（pO（2））随时间的自发波动。方法：pO（2）图是在直接瘤内给药氟化合物（六氟苯）后产生的，其弛豫率（1/T-1）与% O-2成正比。作者在4.7 T下使用SNAP反转恢复序列以高空间和时间分辨率获取T-1弛豫时间的参数图像。自制的例程被开发来执行感兴趣的区域分析，以及pO（2）随时间的逐像素分析。结果：作者能够量化和探测肿瘤pO（2）中自发波动的异质性：（i）pO（2）中的自发波动发生而与基础氧合状态无关（即，在含氧和缺氧区域）和（ii）以1个周期/12-47分钟的速率发生自发波动。为了验证，在未发生急性变化的死亡小鼠中进行了分析。作者由此证明，F-19 MRI技术对肿瘤中pO（2）的急性变化敏感。结论：这是第一种允许使用look-locker方法（例如，SNAP IR）。这种方法可能是一个重要的工具，以表征肿瘤急性缺氧现象，了解其生理病理学，并改善治疗。(C)2010年美国医学物理学家协会。[DOI：10.1118/1.3484056]
Purpose: Acute hypoxia (transient cycles of hypoxia-reoxygenation) is known to occur in solid tumors and may be a poorly appreciated therapeutic problem as it can be associated with resistance to radiation therapy, impaired delivery of chemotherapeutic agents, or metastasis development. The objective of the present study was to use MR F-19 relaxometry maps to analyze the spontaneous fluctuations of partial pressure of oxygen (pO(2)) over time in experimental tumors.Methods: The pO(2) maps were generated after direct intratumoral administration of a fluorine compound (hexafluorobenzene) whose relaxation rate (1/T-1) is proportional to the % O-2. The authors used a SNAP inversion-recovery sequence at 4.7 T to acquire parametric images of the T-1 relaxation time with a high spatial and temporal resolution. Homemade routines were developed to perform regions of interest analysis, as well as pixel by pixel analysis of pO(2) over time.Results: The authors were able to quantify and probe the heterogeneity of spontaneous fluctuations in tumor pO(2): (i) Spontaneous fluctuations in pO(2) occurred regardless of the basal oxygenation state (i.e., both in oxygenated and in hypoxic regions) and (ii) spontaneous fluctuations occurred at a rate of 1 cycle/12-47 min. For validation, the analysis was performed in dead mice for which acute changes did not occur. The authors thereby demonstrated that F-19 MRI technique is sensitive to acute change in pO(2) in tumors.Conclusions: This is the first approach that allows quantitative minimally invasive measurement of the spontaneous fluctuations of tumor oxygenation using a look-locker approach (e.g., SNAP IR). This approach could be an important tool to characterize the phenomenon of tumor acute hypoxia, to understand its physiopathology, and to improve therapies. (C) 2010 American Association of Physicists in Medicine. [DOI: 10.1118/1.3484056]