目的：建立最接近正常成人脑白质弛豫时间的琼脂及钆对比剂浓度配比的磁共振实验模型。方法：将浓度为0.03 mmol/L、0.06 mmol/L、0.09 mmol/L、0.2 mmol/L、0.4 mmol/L、0.6 mmol/L及0.8 mmol/L的钆特酸葡胺分别与1.0%、1.5%（g/dl）的琼脂混合制成模型。将模型固定于成人志愿者头颅周围行MRI扫描得到T1、T2 map图。测定各种浓度配比模型的弛豫时间，分别得到T1、T2值的回归方程。通过单变量求解计算出接近人脑白质弛豫时间95%可信区间（均值）的浓度配比。并根据计算得到的浓度配比配制成模型后与志愿者脑白质弛豫时间作进一步对比验证。结果：人脑白质T1、T2值95%可信区间（均值）分别为792.14~848.59（820.36） ms、83.45~86.09（84.77） ms。0.10~0.11 mmol/L（0.11 mmol/L）钆特酸葡胺与1%琼脂混合、0.09~0.10 mmol/L（0.10 mmol/L）钆特酸葡胺与1.5%琼脂混合后的弛豫时间与脑白质T1值95%可信区间上限值与下限值（均值）接近；0.49~0.56 mmol/L（0.52 mmol/L）钆特酸葡胺与1%琼脂混合、0.08~0.12 mmol/L（0.10 mmol/L）钆特酸葡胺与1.5%琼脂混合的弛豫时间与脑白质T2值95%可信区间上限值与下限值（均值）近似。结论：1.5%的琼脂与0.09~0.10 mmol/L的钆特酸葡胺配比制成的模型T1、T2值均接近正常成人脑白质，能用于模拟正常成人的脑白质MRI信号。
Abstract
Objective: To set up an MR study model for an appropriate mix ratio of agar and gadoteric acid similar to the relaxation time of white matter of adult brain. The mixture is expected to be a substitution of adult brain in MRI experiment. Methods: After a phantom was made of 0.03 mmol/L, 0.06 mmol/L, 0.09 mmol/L, 0.2 mmol/L, 0.4 mmol/L, 0.6 mmol/L, 0.8 mmol/L gadoteric acid mixed with 1%(g/dl) and 1.5%(g/dl) agar respectively, it was fixed around adult brains(n=11) to be scanned by a 1.5T superconducting unit to get T1 and T2 maps. Then the curve equations were fitted by regression analysis of T1, T2 values of every mixture. Single goal seeking was used to calculate the ranges of mix ratio matching to the relaxation times of 95% CI(means) of brain white matter. According to the calculated mix ratio, another phantom was made to compare it’s relaxation times to the white matter. Results: The 95% CIs(means) of T1 and T2 of white matter were 792.14~848.59(820.36) ms and 83.45~86.09(84.77) ms, respectively. The calculated mix ratio matching to the 95% CI(means) of T1 of white matter as follow: 0.10~0.11 mmol/L(0.11 mmol/L) gadoteric acid mixed with 1% agar, 0.09~0.10 mmol/L(0.10 mmol/L) gadoteric acid mixed with 1.5% agar. The calculated mix ratio matching to the 95% CI(means) of T2 of white matter as follow: 0.49~0.56 mmol/L(0.52 mmol/L) gadoteric acid mixed with 1% agar, 0.08~0.12 mmol/L(0.10 mmol/L) gadoteric acid mixed with 1.5% agar. Conclusion: A range of 0.09~0.10 mmol/L gadoteric acid mixed with 1.5% agar is an appropriate mix ratio matching to the both T1 and T2 value of adult brain white matter, which can provide an analog MRI signal of human white matter.
关键词
脑 /
凝胶类 /
磁共振成像
Key words
Brain /
Gels /
Magnetic resonance imaging
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