Department of Physics, Science and Arts Faculty, Cukurova University, 01330, Adana, Turkey.
Department of Medical Physics, Velindre Cancer Centre, CF14 2TL, Cardiff, UK.
Med Phys. 2018 Jun;45(6):2476-2485. doi: 10.1002/mp.12907. Epub 2018 Apr 27.
The aim of this work was to create tissue-mimicking gel phantoms appropriate for diffusion kurtosis imaging (DKI) for quality assurance, protocol optimization, and sequence development.
A range of agar, agarose, and polyvinyl alcohol phantoms with concentrations ranging from 1.0% to 3.5%, 0.5% to 3.0%, and 10% to 20%, respectively, and up to 3 g of glass microspheres per 100 ml were created. Diffusion coefficients, excess kurtosis values, and relaxation rates were experimentally determined.
The kurtosis values for the plain gels ranged from 0.05 with 95% confidence interval (CI) of (0.029,0.071) to 0.216(0.185,0.246), well below the kurtosis values reported in the literature for various tissues. The addition of glass microspheres increased the kurtosis of the gels with values up to 0.523(0.465,0.581) observed for gels with the highest concentration of microspheres. Repeat scans of some of the gels after more than 6 months of storage at room temperature indicate changes in the diffusion parameters of less than 10%. The addition of the glass microspheres reduces the apparent diffusion coefficients (ADCs) and increases the longitudinal and transverse relaxation rates, but the values remain comparable to those for plain gels and tissue, with ADCs observed ranging from 818(585,1053) × 10 mm /s to 2257(2118,2296) × 10 mm /s, R values ranging from 0.34(0.32,0.35) 1/s to 0.51(0.50,0.52) 1/s, and R values ranging from 9.69(9.34,10.04) 1/s to 33.07(27.10, 39.04) 1/s.
Glass microspheres can be used to effectively modify diffusion properties of gel phantoms and achieve a range of kurtosis values comparable to those reported for a variety of tissues.
本工作旨在创建适用于扩散峰度成像（DKI）的组织模拟凝胶体模，以进行质量保证、方案优化和序列开发。
我们创建了一系列琼脂、琼脂糖和聚乙烯醇体模，浓度范围分别为 1.0%至 3.5%、0.5%至 3.0%和 10%至 20%，以及每 100 ml 多达 3 g 的玻璃微球。通过实验确定了扩散系数、超峰度值和弛豫率。
普通凝胶的峰度值范围为 0.05（置信区间 95%为 0.029-0.071）至 0.216（0.185-0.246），远低于文献中报道的各种组织的峰度值。加入玻璃微球会增加凝胶的峰度，最高浓度微球的凝胶峰度值高达 0.523（0.465-0.581）。室温下储存 6 个月以上的一些凝胶重复扫描表明，扩散参数的变化小于 10%。加入玻璃微球会降低表观扩散系数（ADC）并增加纵向和横向弛豫率，但这些值仍与普通凝胶和组织的值相当，观察到的 ADC 值范围为 818（585-1053）×10 -3 mm 2/s 至 2257（2118-2296）×10 -3 mm 2/s，R 值范围为 0.34（0.32-0.35）1/s 至 0.51（0.50-0.52）1/s，R 2 值范围为 9.69（9.34-10.04）1/s 至 33.07（27.10-39.04）1/s。
玻璃微球可有效改变凝胶体模的扩散特性，实现与多种组织报道相当的峰度值范围。
