INCREASING BOTH RESOLUTION & SIGNAL TO NOISE RATIO IN MRI

提高分辨率

• 批准号: 6495447
• 负责人: ERIK K INSKO
• 金额: $ 22.55万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6495447
• 关键词: bioengineering /biomedical engineering; bioimaging /biomedical imaging; biological products; biomedical equipment development; biomedical resource; magnetic resonance imaging; radiology; technology /technique

The advantages of high field MR Imaging have brought with it the disadvantages of increased power delivered to MRI coils. This has forced the MR community to struggle with a method to determine specific absorption rates in tissues subjected to MRI procedures. For transmit/receive surface coils, the electric field is highest at the capacitors. For a birdcage coil, the electric field increases as the square of the distance outwards from the center of the coil. It is the interaction of the electric field with the tissue which theoretically causes local heating. However, it is unclear what, in practice this heating might be, if at all. We have found a temperature dependent chemical shift for Na4HTm[DOTP]2-. This shift is very near 0.5 PPM per oC, both for a solution and in agarose. We then constructed a large agarose phantom with Na4HTm[DOTP]2- and performed 30 minute long imaging experiments, both with the birdcage and the surface coils. We monitored the chemical shift during the experiment and found it to not change at all. In addition, phase images of the phantom describe areas of local heating in the sample. In the phase images, we found no areas of local heating, in either the surface coils or the birdcage coil, even right on top of the capacitors. These preliminary results indicate the usefulness of this compound for determining heat deposition by MRI coils.

高场磁共振成像的优势带来了 增加 MRI 线圈功率的缺点。 这有 迫使 MR 社区努力寻找一种方法来确定 接受 MRI 程序的组织中的特定吸收率。 为了 发射/接收表面线圈，电场最高 电容器。 对于鸟笼线圈，电场随着 从线圈中心向外距离的平方。 这是 电场与组织的相互作用 理论上会引起局部加热。 然而，目前尚不清楚，在 实践这种加热可能是，如果有的话。 我们发现了与温度相关的化学位移 Na4HTm[DOTP]2-。 这种转变非常接近每 oC 0.5 PPM，对于 溶液和琼脂糖中。 然后我们构建了一个大型琼脂糖模型 与Na4HTm[DOTP]2-并进行30分钟长的成像实验， 都有鸟笼和表面线圈。 我们监测了 实验过程中发生化学位移，发现它在 全部。 此外，模型的相位图像描述了局部区域 在样品中加热。 在相位图中，我们没有发现任何区域 局部加热，无论是表面线圈还是鸟笼线圈，甚至 就在电容器的顶部。 这些初步结果表明 该化合物在通过 MRI 测定热沉积方面的用途 线圈。