目的:制备和分析大豆-卵磷脂-琼脂凝胶,用于在3T时具有组织样弛豫时间的无毒弛豫测量法体模。
方法:模拟各种组织(灰质和白质,肾皮质和髓质,脾,脾肌肉,肝脏)用临床3T全身MR扫描仪进行构建和测试。推导了简单的方程式,以计算水溶液中大豆卵磷脂和琼脂的适当浓度,以实现所需的弛豫时间。测试了幻影的测量值与计算的T1和T2值之间的对应关系,再现性,空间同质性,和时间稳定性。应用了T1和T2映射技术以及具有高空间分辨率的3DT1加权序列。
结果:除了肝脏松弛体模,所有的幻影都是成功和可重复地生产的。在目标和测量的弛豫时间之间发现了良好的一致性。与目标弛豫时间的百分比偏差对于T1小于3%,对于T2小于6.5%。此外,幻影是均匀的,几乎没有气泡。然而,随着时间的推移,幻影是不稳定的:在4周的储存期后,在几乎所有的幻影中都检测到霉菌的生长和弛豫时间的变化。
结论:大豆-卵磷脂-琼脂凝胶是一种无毒材料,可用于构建具有组织样弛豫时间的弛豫测量模型。他们很容易准备,廉价和允许T1和T2的独立调整。然而,改善幻影的长期稳定性仍有工作要做。
OBJECTIVE: To prepare and analyze soy-lecithin-agar gels for non-toxic relaxometry phantoms with tissue-like relaxation times at 3T.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.