NEW PULSE SEQUENCE FOR INDIRECT DETECTION OF 17O IN BRAIN

用于间接检测大脑中 17O 的新脉冲序列

• 批准号: 6657633
• 负责人: SRIDHAR R CHARAGUNDLA
• 金额: $ 22.55万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6657633
• 关键词: bioimaging /biomedical imaging; biological products; biomedical resource; child (0-11); female; human subject; magnetic resonance imaging; male; nuclear magnetic resonance spectroscopy

During our continued effort to measure iron level in tissue, we have developed two novel methods for the measurement of magnetic susceptibility. Before applying these techniques to humans, we need to conduct thorough phantom and animal studies. Significant progress has been made in this direction. In the first technique, called the contact reference method, a series of gerbil mice were injected iron dextran solutions to induce iron overload to different levels. Then we measured their liver and heart magnetic susceptibilities ex vivo. At the same time, these samples were sent to an independent lab to measure their iron concentrations using atomic absorption spectroscopy. We have found that sample magnetic susceptibilities are linearly proportional to their iron concentrations. Another susceptibility measurement we have developed is the dipole field model. First, a test tube was inserted in a big flask filled with water. We acquired the phase image of a slice in the coronal direction. Then a small sample (solid or liquid) was placed in the test tube. Under the same experimental conditions, we took the measurement again. The two phase image difference provides the magnetic field generated by the sample magnetization. We approximated the sample to a magnetic dipole, ignoring all other higher order field, and then modelled the magnetic field of sample to the dipole field formula. This way, we could extract the magnetic susceptibility of sample. Computer simulation shows that the dipole field approximation introduces very small error. Currently we are seeking to apply this method to mapping brain magnetic susceptibility.

在我们持续衡量组织中铁水平的努力中，我们 已经开发了两种用于测量磁的新方法 敏感性。 在将这些技术应用于人类之前，我们需要 进行彻底的幻影和动物研究。 取得重大进展 已经朝这个方向制作。 在第一个技术中，称为接触参考方法 注入铁葡聚糖溶液以诱导一系列的沙鼠小鼠 铁超负荷到不同的水平。 然后我们测量了他们的肝脏， 心脏磁敏感性在体内。 同时，这些 样品被送到独立实验室以测量其铁 使用原子吸收光谱法浓度。 我们找到了 样品磁敏感性与 他们的铁浓度。 我们开发的另一个敏感性测量是 偶极场模型。 首先，将试管插入大瓶中 充满水。 我们获得了切片的相位图像 冠状方向。 然后放置一个小样品（固体或液体） 在试管中。 在相同的实验条件下，我们接受了 再次测量。 两个相图差提供了 样品磁化产生的磁场。 我们近似 样品到磁偶极子，忽略所有其他高阶 场，然后对样品的磁场建模到偶极子 现场公式。 这样，我们可以提取磁化率 样品。 计算机模拟显示偶极子场 近似引入了非常小的错误。 目前我们正在寻找 将此方法应用于映射大脑磁敏感性。