二维相位对比MRI在稳态流体模型的定量测量

Quantitative Measurement of Flow Velocity with a Phantom by 2D PC-MRI

目的:制作稳态流体模型并改变各种参数来评价二维相位对比(2D-PC)MRI定量测量的准确性。方法:流速模型包括塑胶管(直径3.3 mm),0.9%生理盐水2000 ml、新鲜牛奶2000 ml,高压注射器一台。通过改变模型的管道倾斜度(90°、45°)、流体的性质(牛奶、盐水)和注入流速(5.0、7.5、10.0和12.5 cm/s),并采用不同流速编码值(20和30 cm/s)行2D-PC法MRI,通过后处理软件获得不同条件下的流速测量值并与实际值比较,所有数据由两位高年资MRI医师进行测量和分析。结果:采用2D-PC MRI对流体模型进行测量并与实际流速比较,不同流速编码(F=0.01,P=0.999)、不同塑胶管倾斜度(F=0.034,P=0.966)及不同流体类型(F=0.006,P=0.994)时,测量流速值与实际值的差异均无统计学意义。结论:二维相位对比MRI是一种较准确的血流定量测量技术。

Objective：To assess the accuracy of quantitative measurement with 2D PC MRI by a flow velocity phantom by setting various parameters. Methods：Flow velocity phantom included a plastic tube （3.3mm in diameter）, different property of liquid （normal saline, 2000ml; fresh milk, 2000ml） and a high pressure injector. Flow velocity measurements with the phantom were acquired by setting various parameters including inclination angle of the plastic tube （90° or 45°） , and different fluid properties （normal saline,milk） and velocity of fluid injection （5.0cm/s,7.5 cm/s and 12.5cm/s）. 2D- PC MRI were performed with different velocity coding （20cm/s,30cm/s）. Measurements of velocity with different situation were acquired with post processing soft ware and compared with the real objective value. All data were measured and analyzed by two senior MR specialists independently. Results： There were no significant statistical differences between the real velocity and the results of measurement by setting velocity with v=20cm/s or v=30cm/s （F=0.01 ,P=0. 999） ,as well as putting the tube inclination angle in 90° or 45°（F= 0. 034, P = 0. 966） or injection of different kinds of fluid （normal saline or milk） （F=0. 006, P = 0. 994）. Conclution： 2D Phase contrast MR imaging proved to be an accurate technique in the quantitative measurement of blood flow.