Katz J, Peshock R M, McNamee P, Schaefer S, Malloy C R, Parkey R W
Magn Reson Med. 1987 Apr;4(4):307-22. doi: 10.1002/mrm.1910040402.
The effects of pulsatile flow on spin phases in spin-echo magnetic resonance imaging are considered. General expressions for the spin phases of the first four echoes are derived in terms of the Fourier coefficients of flow. These expressions are valid for any time-dependent acceleration and, hence, are not restricted to constant acceleration. The derived expressions are then theoretically evaluated for aortic flow and examined at different points in the cardiac cycle. Our results show that rephasing may occur at certain points in the cardiac cycle for either even or odd echoes depending upon the particular Fourier coefficients of the velocity function and the spin-echo delay time. However, even-echo rephasing is not always necessarily valid. Furthermore, the possibility of determining the flow velocities in the body with an appropriate series of imaging studies is also discussed.
考虑了脉动流对自旋回波磁共振成像中自旋相位的影响。根据流动的傅里叶系数，推导出了前四个回波自旋相位的一般表达式。这些表达式适用于任何随时间变化的加速度，因此不限于恒定加速度。然后从理论上对导出的表达式进行主动脉血流评估，并在心动周期的不同点进行检查。我们的结果表明，根据速度函数的特定傅里叶系数和自旋回波延迟时间，在心动周期的某些点，偶数或奇数回波都可能发生重聚相。然而，偶数回波重聚相并不总是必然成立。此外，还讨论了通过一系列适当的成像研究来确定体内血流速度的可能性。
