中文摘要：

目的 探讨相位对比法MRI（PC—MRI）测量肺动脉血流的准确性以及临床应用价值。方法 ①选取正常健康志愿者42例，随机分为2组，采用PC—MRI和多普勒超声测量了主肺动脉的内径、最大流速和平均流速。②采用公式分别计算出主肺动脉1个心动周期的血流量。结果 ①PC—MRI和多普勒超声测量主肺动脉的内径分别为（24．4±3、41）mm和（21．5±2．55）mm。②PC—MRI测量主肺动脉的最大流速和平均流速分别为（79．9±24．0）cm／s和（50．3±7．71）cm／s。③多普勒超声测量主肺动脉的最大流速和平均流速分别为（88．8±833）cm／s和（53．7±5．04）cm／s。④PC—MRI测量主肺动脉的血流量为（73．5±6．60）ml，多普勒超声测量主肺动脉的血流量为（69．0±10．6）ml。应用统计学方法成组样本均数t-检验分析2种测量结果，选择检验水平为α为0．05。结论 PC—MRI可以准确测量肺动脉的血流速度和血流量，对评价肺动脉血流动力学的改变具有一定价值。

英文摘要：

Objective To investigate the accuracy and applied value of measurement of pulmonary flow velocity with phase-contrast MRI（PC-MRI）.Methods ①42 healthy volunteers were divided into 2 groups randomly, one group was examined by PC-MRI, another was examined by doppler ultrasound. The inner diameter, maximum velocity and mean velocity of main pulmonary artery （MPA） were measured ; ②The flow volume of MPA in a cardiac cycle was calculated with formulation. Results ①The inner diameters of MPA measured with PC-MRI and doppler ultrasound were （24.4±3.41） mm and （21.5±2.55） mm respectively ;②The maximum velocity and mean velocity of MPA measured by PC MRI were （79.9±24.0） cm/s and （50.3±7.71） cm/s respeetively;③The maximum velocity and mean velocity of MPA gained by doppler uhrasound was （ 88.8±8.33 ） cm/s and （ 53.7±5.04 ） cm/s resepeetively ; ④The flow volume of MPA in a cardiac cycle measured by PC MRI and doppler ultrasound was （73.5±6.60） ml and （69.0±10.6） ml respectively. The results were analyzed by group sample t - test, and the level of test was 0.05. Conclusion The blood flow velocity and volume of pulmonary artery can be measured accurately by PC-MRI, it is of certain applied value in assessing the pulmonary blood flow dynamies changes.