水凝胶、顺磁盐溶液及油在0.35T、1.5T、3T下的T1、T2及复介电常数
T1, T2, and complex permittivities of hydrogels, paramagnetic salt solutions, and oils at 0.35, 1.5, and 3 Tesla
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中文总结 AI 辅助
该研究测量了水凝胶等MRI体模成分在不同磁场下的T1、T2及复介电常数，筛选出适合高场低介电体模的油类及多种优良水凝胶候选材料。
中文摘要 AI 辅助
方法：测量了候选MRI体模成分（水凝胶、顺磁电解质、油）在不同磁场强度和浓度下的T1、T2及复介电常数。数据：除PEG外，T1随浓度升高而降低；聚乙二醇（PEG）、聚乙烯吡咯烷酮（PVP）、聚丙烯酸钠及去离子水的T1、T2弛豫率未随磁场强度显著变化；明胶、海藻酸钠的T2弛豫率未随磁场强度显著变化；所有水凝胶和顺磁电解质溶液均具有与水相似的高静态介电常数（如εs≈70）；Miller's LB琼脂、明胶、PVA、海藻酸钠、聚丙烯酸钠、黄原胶、CuSO4、NiCl2、Mn(NO3)2的静态电导率随浓度升高而上升，而PEG和PVP的电导率未随浓度升高而上升。结论：聚丙烯酸钠、PVP及PEG水凝胶难以制备出一致性良好的体模；海藻酸钠、Miller's LB琼脂、黄原胶是优良的水凝胶候选材料；Mn(NO3)2在测试样品中具有最高的弛豫率；三种油（菜籽油、蓖麻油、葡萄籽油）均是高场应用中低介电（εs<10）体模的优良候选材料，且电导率较低。
英文摘要
Approach: The T1, T2, and complex permittivities of candidate MRI phantom constituents (hydrogels, paramagnetic electrolytes, and oils) were measured at different magnetic field strengths and concentrations. Data: T1 decreased with increasing concentration except for PEG. The T1 and T2 relaxivities of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), sodium polyacrylate, and deionized water did not significantly vary with field strength. The T2 relaxivities of gelatin and sodium alginate did not significantly vary with field strength. All of the hydrogels and paramagnetic electrolyte solutions had high static dielectrics (e.g., εs~70) similar to water. The static electrical conductivities of Miller's LB agar, gelatin, PVA, sodium alginate, sodium polyacrylate, xanthan gum, CuSO4, NiCl2, and Mn(NO3)2 rose with concentration. However, the conductivities of PEG and PVP did not rise with concentration. Conclusions: Sodium polyacrylate, PVP, and PEG hydrogels are challenging for generating consistent phantoms. Sodium alginate, Miller's LB agar, and xanthan gum were good hydrogel candidates. Mn(NO3)2 had the highest relaxivities of the tested samples. All three oils (canola, castor, and grapeseed) are good candidates for low dielectric (εs<10) phantoms for high field applications) but with low conductivities.
