• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of magnetic resonance >Microtesla MRI with dynamic nuclear polarization
【24h】

Microtesla MRI with dynamic nuclear polarization

机译：具有动态核极化的Microtesla MRI

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Magnetic resonance imaging at microtesla fields is a promising imaging method that combines the pre-polarization technique and broadband signal reception by superconducting quantum interference device (SQUID) sensors to enable in vivo MRI at microtesla-range magnetic fields similar in strength to the Earth magnetic field. Despite significant advances in recent years, the potential of microtesla MRI for biomedical imaging is limited by its insufficient signal-to-noise ratio due to a relatively low sample polarization. Dynamic nuclear polarization (DNP) is a widely used approach that allows polarization enhancement by 2-4 orders of magnitude without an increase in the polarizing field strength. In this work, the first implementation of microtesla MRI with Overhauser DNP and SQUID signal detection is described. The first measurements of carbon-13 NMR spectra at microtesla fields are also reported. The experiments were performed at the measurement field of 96 μT, corresponding to Larmor frequency of 4 kHz for protons and 1 kHz for carbon-13. The Overhauser DNP was carried out at 3.5-5.7 mT fields using rf irradiation at 120 MHz. Objects for imaging included water phantoms and a cactus plant. Aqueous solutions of metabolically relevant sodium bicarbonate, pyruvate, alanine, and lactate, labeled with carbon-13, were used for NMR studies. All the samples were doped with TEMPO free radicals. The Overhauser DNP enabled nuclear polarization enhancement by factor as large as -95 for protons and as large as -200 for carbon-13, corresponding to thermal polarizations at 0.33 T and 1.1 T fields, respectively. These results demonstrate that SQUID-based microtesla MRI can be naturally combined with Overhauser DNP in one system, and that its signal-to-noise performance is greatly improved in this case. They also suggest that microtesla MRI can become an efficient tool for in vivo imaging of hyperpolarized carbon-13, produced by low-temperature dissolution DNP.
机译：微特斯拉场的磁共振成像是一种很有前途的成像方法，将超极化量子干扰设备（SQUID）传感器与预极化技术和宽带信号接收相结合，可以在强度类似于地球磁场的微特斯拉范围磁场中进行体内MRI 。尽管近年来取得了重大进展，但由于样品极化相对较低，因此微特斯拉MRI在生物医学成像方面的潜力受到信噪比不足的限制。动态核极化（DNP）是一种广泛使用的方法，它可以将极化增强2-4个数量级，而不会增加极化场强度。在这项工作中，描述了具有特豪斯DNP和SQUID信号检测的微特斯拉MRI的第一种实现方式。还报道了在微特斯拉场上碳13 NMR光谱的首次测量。实验在96μT的测量场上进行，这对应于质子为4 kHz的拉莫尔频率和碳13为1 kHz的拉莫尔频率。使用120 MHz的射频辐射在3.5-5.7 mT的场上进行Overhauser DNP。用于成像的对象包括水体模和仙人掌植物。代谢相关的碳酸氢钠，丙酮酸，丙氨酸和乳酸的水溶液（用碳13标记）用于NMR研究。所有样品都掺有TEMPO自由基。 Overhauser DNP使质子的核极化增强高达-95，而碳13的核极化增强高达-200，分别对应于0.33 T和1.1 T场的热极化。这些结果表明，基于SQUID的微特斯拉MRI可以与Overhauser DNP自然地组合在一个系统中，并且在这种情况下其信噪比性能得到了极大的改善。他们还建议，微特斯拉MRI可以成为由低温溶解DNP产生的超极化碳13体内成像的有效工具。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号