Morgan V L, Price R R, Lorenz C H
Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA.
Magn Reson Imaging. 1996;14(9):1043-51. doi: 10.1016/s0730-725x(96)00222-6.
The goal of this study was to use linear optimization techniques as a systematic method of cine phase contrast pulse sequence design and to apply this technique to the measurement of blood flow in vivo. The optimized waveforms were validated in a constant flow phantom with average velocities ranging from 5 to 50 cm/s. The same optimized sequence was also run in a segmented k-space variation with five phase encoding lines per segment. The magnetic resonance (MR) derived velocity measurements were accurate over the entire range of velocities tested (p < .05) in both cases. The same optimized pulse sequence was applied to the measurement of flow in main pulmonary artery of five normal volunteers and compared with stroke volumes and cardiac outputs calculated from right ventricular volume measurements. These measurements showed a mean difference between the MR phase contrast calculated stroke volume and the volumetric stroke volume measurement of 9.8 +/- 11.6%. The mean difference between the calculated phase contrast cardiac output and the volumetric cardiac output was 4.4 +/- 10%. These results imply that optimization techniques are an efficient method for designing cine phase contrast pulse sequences.
本研究的目的是使用线性优化技术作为电影相位对比脉冲序列设计的系统方法，并将该技术应用于体内血流测量。在平均速度范围为5至50 cm/s的恒流体模中对优化后的波形进行了验证。相同的优化序列也在分段k空间变化中运行，每段有五条相位编码线。在两种情况下，磁共振（MR）得出的速度测量值在整个测试速度范围内都是准确的（p < 0.05）。将相同的优化脉冲序列应用于五名正常志愿者主肺动脉血流的测量，并与根据右心室容积测量计算出的每搏量和心输出量进行比较。这些测量结果显示，MR相位对比法计算的每搏量与容积法测量的每搏量之间的平均差异为9.8 +/- 11.6%。计算得出的相位对比心输出量与容积法心输出量之间的平均差异为4.4 +/- 10%。这些结果表明，优化技术是设计电影相位对比脉冲序列的有效方法。
