Section of Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany.
Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany.
MAGMA. 2024 Oct;37(5):899-907. doi: 10.1007/s10334-024-01166-7. Epub 2024 May 11.
To prepare and analyze soy-lecithin-agar gels for non-toxic relaxometry phantoms with tissue-like relaxation times at 3T.
Phantoms mimicking the relaxation times of various tissues (gray and white matter, kidney cortex and medulla, spleen, muscle, liver) were built and tested with a clinical 3T whole-body MR scanner. Simple equations were derived to calculate the appropriate concentrations of soy lecithin and agar in aqueous solutions to achieve the desired relaxation times. Phantoms were tested for correspondence between measurements and calculated T1 and T2 values, reproducibility, spatial homogeneity, and temporal stability. T1 and T2 mapping techniques and a 3D T1-weighted sequence with high spatial resolution were applied.
Except for the liver relaxation phantom, all phantoms were successfully and reproducibly produced. Good agreement was found between the targeted and measured relaxation times. The percentage deviations from the targeted relaxation times were less than 3% for T1 and less than 6.5% for T2. In addition, the phantoms were homogeneous and had little to no air bubbles. However, the phantoms were unstable over time: after a storage period of 4 weeks, mold growth and also changes in relaxation times were detected in almost all phantoms.
Soy-lecithin-agar gels are a non-toxic material for the construction of relaxometry phantoms with tissue-like relaxation times. They are easy to prepare, inexpensive and allow independent adjustment of T1 and T2. However, there is still work to be done to improve the long-term stability of the phantoms.
制备和分析大豆卵磷脂-琼脂凝胶，以在 3T 下获得具有类似组织弛豫时间的无毒弛豫度体模。
构建了模拟各种组织（灰质和白质、肾皮质和髓质、脾、肌肉、肝）弛豫时间的体模，并在临床 3T 全身磁共振扫描仪上进行了测试。推导出了简单的方程，以计算在水溶液中获得所需弛豫时间所需的大豆卵磷脂和琼脂的适当浓度。测试了体模的测量值与计算的 T1 和 T2 值、重现性、空间均匀性和时间稳定性之间的一致性。应用了 T1 和 T2 映射技术和具有高空间分辨率的 3D T1 加权序列。
除了肝脏弛豫体模外，所有体模都成功且可重复地制备。目标和测量的弛豫时间之间存在良好的一致性。T1 的偏差百分比小于 3%，T2 的偏差百分比小于 6.5%。此外，体模均匀且几乎没有气泡。然而，体模随时间不稳定：在 4 周的储存期后，几乎所有体模中都检测到霉菌生长和弛豫时间的变化。
大豆卵磷脂-琼脂凝胶是一种用于构建具有类似组织弛豫时间的弛豫度体模的无毒材料。它们易于制备、价格低廉，并允许独立调整 T1 和 T2。然而，仍需要进一步改进体模的长期稳定性。
