Accuracy and Precision of MR Blood Oximetry Based on the Long Paramagnetic Cylinder Approximation of Large Vessels
Accuracy and Precision of MR Blood Oximetry Based on the Long Paramagnetic Cylinder Approximation of Large Vessels
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DOI：
10.1002/mrm.21981
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发表时间：
2009-08-01
影响因子：
3.3
通讯作者：
Wehrli, Felix W.
中科院分区：
文献类型：
--
作者：
Langham, Michael C.;Magland, Jeremy F.;Wehrli, Felix W.
一种准确的无创测量深血管血红蛋白氧饱和度（%HbO(2)）的方法将具有许多临床应用价值。定量MRI可能是唯一的成像方式，可以解决这个困难和重要的问题。用于测量大血管血氧饱和度的基于磁共振电纳的血氧饱和度法将血管建模为浸入外场的长顺磁圆柱体。相对于周围肌肉组织的血管内磁化率是含氧血红蛋白（HbO(2)）的一个功能，可以用场映射脉冲序列来量化。本文根据任意定向圆柱体的解析表达式，从理论上考察了该方法的准确性和精密度，并在3T场强下对股动脉和股静脉进行了模拟实验和活体实验。评估了由容器倾斜、容器截面非圆度和感应磁场梯度引起的误差，设计并实现了校正方法。在连续的血管段测量血红蛋白饱和度，不同的几何形状，如偏心和血管倾斜，但恒定的血氧饱和度水平，作为评估测量一致性的手段。幻影测量的平均标准误差和变异系数为
An accurate noninvasive method to measure the hemoglobin oxygen saturation (%HbO(2)) of deep-lying vessels without catheterization would have many clinical applications. Quantitative MRI may be the only imaging modality that can address this difficult and important problem. MR susceptometry-based oximetry for measuring blood oxygen saturation in large vessels models the vessel as a long paramagnetic cylinder immersed in an external field. The intravascular magnetic susceptibility relative to surrounding muscle tissue is a function of oxygenated hemoglobin (HbO(2)) and can be quantified with a field-mapping pulse sequence. In this work, the method's accuracy and precision was investigated theoretically on the basis of an analytical expression for the arbitrarily oriented cylinder, as well as experimentally in phantoms and in vivo in the femoral artery and vein at 3T field strength. Errors resulting from vessel tilt, noncircularity of vessel cross-section, and induced magnetic field gradients were evaluated and methods for correction were designed and implemented. Hemoglobin saturation was measured at successive vessel segments, differing in geometry, such as eccentricity and vessel tilt, but constant blood oxygen saturation levels, as a means to evaluate measurement consistency. The average standard error and coefficient of variation of measurements in phantoms were