Quantifying effective magnetic moments of narrow cylindrical objects in MRI
Quantifying effective magnetic moments of narrow cylindrical objects in MRI
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DOI：
10.1088/0031-9155/54/22/018
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发表时间：
2009-11-21
影响因子：
3.5
通讯作者：
Haacke, E. Mark
中科院分区：
文献类型：
--
作者：
Cheng, Yu-Chung N.;Hsieh, Ching-Yi;Haacke, E. Mark
提出了一种精确测量长圆柱体有效磁矩的新方法。在我们的方法中，自然地包括和克服了部分体积，脱相和相位混叠效应。从一个典型的梯度回波序列在一个单一的回波时间的图像通常足以量化有效磁矩的圆柱形物体。只需要物体附近的像素。该方法可以准确地量化磁矩，并区分圆柱形物体之间横截面的亚像素变化。通过误差传播法研究了程序的不确定性。用不同参数下获取的图像验证了方法的鲁棒性。讨论了提取不同方向物体磁矩的不同方法及其局限性。我们的方法有可能应用于任何截面接近圆盘的长物体。
A new procedure for accurately measuring effective magnetic moments of long cylinders is presented. Partial volume, dephasing and phase aliasing effects are naturally included and overcome in our approach. Images from a typical gradient echo sequence at one single echo time are usually sufficient to quantify the effective magnetic moment of a cylindrical-like object. Only pixels in the neighborhood of the object are needed. Our approach can accurately quantify the magnetic moments and distinguish subpixel changes of cross sections between cylindrical objects. Uncertainties of our procedure are studied through the error propagation method. Images acquired with different parameters are used to test the robustness of our method. Alternate approaches and their limitations to extract magnet moments of objects with different orientations are also discussed. Our method has the potential to be applied to any long object whose cross section is close to a disk.