使用MR光谱学测量聚烯 (PVP) 溶液中的温度
Neville D Gai1, Ruifeng Dong1, Jan Willem van der Veen2
1Laboratory on Quantitative Medical Imaging, NIBIB/NIH, Bethesda, Maryland, USA.
Medical physics
|February 17, 2025
概括
聚烯 (PVP) 溶液可用于使用磁共振 (MR) 谱学准确测量温度. 这种方法可用于校准不同MRI扫描仪的扩散MRI测量.
科学领域:
- 磁共振成像是一种磁共振成像技术.
- 生物医学工程 生物医学工程
- 材料科学 材料科学 材料科学
背景情况:
- 聚烯立 (PVP) 水溶液对于验证跨站点和供应商的扩散测量非常有价值.
- 精确的温度测定至关重要,因为水的扩散性取决于温度.
研究的目的:
- 研究MR光谱 (MRS) 在PVP溶液中绝对温度测量的使用.
- 在三个不同的MRI扫描仪供应商中评估温度测量的可重复性和可重复性.
主要方法:
- 在球形容器中使用40%的PVP w/w溶液.
- 在3T扫描仪 (GE,西门子,飞利浦) 上使用点分辨率光谱 (PRESS) 序列与水抑制.
- 将特定的PVP甲基烯质子峰的频率转移与光纤探测器测量的温度进行映射.
主要成果:
- 在PVP溶液中确定了稳定的质子峰值,与甲基峰相比,水峰值转移了~-0.01 ppm/°C.
- 在扫描仪上表现出极好的重复性 (std范围:0.00-0.14°C) 和可重复性 (平均差异:0.1-0.4°C).
- 来自MRS的温度与内部幽灵的探针测量结果一致,商业幽灵的变化有所不同.
结论:
- PVP 解决方案具有稳定的质子峰值,适合通过 MR 质子光谱进行温度评估.
- 基于MRS的温度测量是快速的,可以使用标准序列进行,并且对于校准扩散MRI至关重要.
- 该技术为扩散测量的跨供应商验证提供了基本数据.
相关概念视频
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
1.0K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.0K
Chemical Shift: Internal References and Solvent Effects
590
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
590
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
1.0K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.0K
¹H NMR of Labile Protons: Temporal Resolution
1.1K
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
1.1K
![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)

