Quantitative determination of Gd-DTPA concentration in T1-weighted MR renography studies
Quantitative determination of Gd-DTPA concentration in T1-weighted MR renography studies
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DOI：
10.1002/mrm.21169
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发表时间：
2007-06-01
影响因子：
3.3
通讯作者：
Lee, Vivian S.
中科院分区：
文献类型：
--
作者：
Bokacheva, Louisa;Rusinek, Henry;Lee, Vivian S.
开发了MR信号强度（SI）的对比度浓度的方法，并验证了用于T-1加权MR肾脏摄影（MRR）研究的方法。该方法基于在GD-DTPA掺杂的水幻象中对SI和松弛时间T-1的参考测量值。在人体组织中观察到了相同形式的SI与T-1依赖性。由提出的方法计算出的对比度浓度在0和1 mm之间没有偏差，并且与使用相对信号方法计算的浓度相比，与直接T-1测量得出的参考值更好地同意。基于幻影的转化率用于确定九名患者的肾脏组织中的对比度浓度，这些患者在1.5T和TC-99M-DTPA放射性核ellide肾脏术（1313）中接受了动态GD-DTPA增强的3D MRR。发现两种对比剂的浓度在幅度上均接近，并且显示出相似的吸收和冲洗行为。如Monte Carlo模拟所示，SNR = 20的SI噪声引起的浓度误差低于10％，而预将对的T-1值的误差为10％，导致0.1和1 mm之间的浓度误差12-17％。预期该提出的方法对于评估高度浓缩对比度的区域特别有用。
A method for calculating contrast agent concentration from MR signal intensity (SI) was developed and validated for T-1-weighted MR renography (MRR) studies. This method is based on reference measurements of SI and relaxation time T-1 in a Gd-DTPA-doped water phantom. The same form of SI vs. T-1 dependence was observed in human tissues. Contrast concentrations calculated by the proposed method showed no bias between 0 and 1 mM, and agreed better with the reference values derived from direct T-1 measurements than the concentrations calculated using the relative signal method. Phantom-based conversion was used to determine the contrast concentrations in kidney tissues of nine patients who underwent dynamic Gd-DTPA-enhanced 3D MRR at 1.5T and Tc-99m-DTPA radionuclide renography (1313). The concentrations of both contrast agents were found to be close in magnitude and showed similar uptake and washout behavior. As shown by Monte Carlo simulations, errors in concentration due to SI noise were below 10% for SNR = 20, while a 10% error in precontrast T-1 values resulted in a 12-17% error for concentrations between 0.1 and 1 mM. The proposed method is expected to be particularly useful for assessing regions with highly concentrated contrast.