目的探讨磁共振相位对比法 (PC-MRI)测量肺动脉瓣前后的血流动 力学改变及临床应用价值。方法 选 取33例健康青年志愿者，使用Siemens SomatonAera 1.5T磁共振系统，Syngo Argus 血流测量软件，做垂直于肺动脉瓣 前后的通过平面的PC-MRI，统计肺动脉瓣 前后的峰值流速(Peak Velocity,PV)、 平均流速(Average Velocity,AV)及 每分钟平均流量(Average Flow Per Minute,AFPM)，比较肺动脉瓣前后的测量 数据，利用Argiento P公式和Bernolli 方程分别计算主肺动脉平均压 ( m e a n pulmonary arterial pressure），标记 为mPAPA及mPAPB，并统计两者肺动脉压力 正常值的差异。结果 本组肺动脉瓣前后 PV、AV无显著差异(P＞0.05)；瓣后AFPM 较瓣前大(P＜0.05)。按照Argiento P公 式及Bernoulli方程计算肺动脉平均压力 (mPAPA,mPAPB)经统计分析，发现二者有 显著差异性(P=0.000)。结论 PC-MRI可以 准确测量肺动脉瓣前后的血流速度及流 量，并可计算其压力值，对研究肺动脉的 血流动力学改变有重要价值，为特发性肺 动脉高压(IPAP)的诊断和评估建立了正常 MRI标准。

Objective To study the blood flow dynamics changes and clinical value of before and after the pulmonary arterial valve with PC-MRI. Methods 33 healthy youth volunteers were enrolled. SiemensSomatonAera 1.5T magnetic resonance system and Syngo Argus flow measurement solfware were used in this study. The peak and average velocity and the average flow per minute before and after the pulmonary arterial valve were measured by perpendicular to the point of 1.5cm before and after the pulmonary valve with through-plane PC-MRI. The main pulmonary arterial mean pressure(mPAP) with Argiento P formula (mPAPA) and Bernolli equation (mPAPB) were calculated and compared separately. Rusults The peak and average velocity before and after the valve had no significant differences(P＞0.05) and there was a statistical differences between that of average flow per minute(P＜0.05). According to the Argiento P formula and Bernoulli equation, the mean pulmonary arterial pressure have diffencese(P=0.000). Conclusion The hemodynamics before and after the pulmonary valve can be measured accurately by PC-MRI, which is a valuable method for assessing the pulmonary blood flow dynamics changes, especially for the diagnosis and evaluation of the Idiopathic pulmonary hypertension.