Pelc N J, Bernstein M A, Shimakawa A, Glover G H
Department of Diagnostic Radiology and Nuclear Medicine, Stanford University School of Medicine, CA 94305-5105.
J Magn Reson Imaging. 1991 Jul-Aug;1(4):405-13. doi: 10.1002/jmri.1880010404.
Three encoding strategies for the measurement of flow velocities in arbitrary directions with phase-contrast magnetic resonance imaging are presented; their noise and dynamic range performance are compared by means of theoretical analysis and computer simulation. A six-point measurement strategy is shown to be quite inefficient in terms of velocity variance per unit time. A simple four-point method exhibits equal dynamic range; its noise depends on flow direction but on average is equal to that of the six-point method. An alternate, balanced four-point method has noise that is direction independent and has, depending on implementation, possibly lower noise levels. Either four-point method is more efficient and is preferred over the six-point approach.
本文介绍了三种用于通过相位对比磁共振成像测量任意方向流速的编码策略；通过理论分析和计算机模拟对它们的噪声和动态范围性能进行了比较。结果表明，就单位时间内的速度方差而言，六点测量策略效率相当低。一种简单的四点方法具有相同的动态范围；其噪声取决于流动方向，但平均而言与六点方法的噪声相等。另一种平衡四点方法的噪声与方向无关，并且根据实现方式的不同，可能具有更低的噪声水平。两种四点方法都更高效，比六点方法更可取。
