An analysis of the accuracy of magnetic resonance flip angle measurement methods
An analysis of the accuracy of magnetic resonance flip angle measurement methods
复制标题
DOI：
10.1088/0031-9155/55/20/008
复制
发表时间：
2010-10-21
影响因子：
3.5
通讯作者：
Schabel, Matthias C.
中科院分区：
文献类型：
--
作者：
Morrell, Glen R.;Schabel, Matthias C.
已经提出了几种用于磁共振成像的翻转角度标测方法。我们评估了在存在测量噪声的情况下，五种翻转角测量方法的准确性。我们的分析是通过概率密度函数(PDF)的传播以封闭的形式进行的。比较的翻转角度映射方法有(1)相敏法，(2)使用梯度回波(GRE)的双角法，(3)包含相位信息的GRE双角法的扩展版本，(4)AFI方法和(5)包含相位信息的AFI方法的扩展版本。在噪声效率的比较中，我们的分析考虑了这些方法所需成像时间的差异。计算了每种方法对于每个真实翻转角值的翻转角度估计的PDF。这些PDF文件完全描述了每种方法的性能。根据这些PDF计算平均偏差和标准偏差，以更简单地量化每种方法在其可测量的翻转角度范围内的相对精度。我们证明了在较宽的翻转角度范围内，相敏方法在五种方法中提供了最低的翻转角度估计的平均偏差和标准偏差。
Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping methods compared were (1) the phase-sensitive method, (2) the dual-angle method using gradient recalled echoes (GRE), (3) an extended version of the GRE dual-angle method incorporating phase information, (4) the AFI method and (5) an extended version of the AFI method incorporating phase information. Our analysis took into account differences in required imaging time for these methods in the comparison of noise efficiency. PDFs of the flip angle estimate for each method for each value of true flip angle were calculated. These PDFs completely characterize the performance of each method. Mean bias and standard deviation were computed from these PDFs to more simply quantify the relative accuracy of each method over its range of measurable flip angles. We demonstrate that the phase-sensitive method provides the lowest mean bias and standard deviation of flip angle estimate of the five methods evaluated over a wide range of flip angles.