Honda N, Machida K, Hashimoto M, Mamiya T, Takahashi T, Kamano T, Kashimada A, Inoue Y, Tanaka S, Yoshimoto N
Department of Radiology, Saitama Medical Center, Saitama Medical School, Japan.
Radiology. 1993 Jan;186(1):189-94. doi: 10.1148/radiology.186.1.8416562.
Aortic regurgitation (AR) in five healthy volunteers and 26 patients (mean age, 60.3 years; range, 25-83 years) was quantitatively measured with magnetic resonance (MR) imaging velocity mapping. Cine transverse images of the ascending aorta (32 phases per cardiac cycle) were acquired by using a gradient-echo sequence with a velocity-encoding bipolar pulse applied in the section-selection direction with a 1.5-T MR imaging unit. The aortic flow was calculated by integrating the product of area and mean velocity of the ascending aorta at each phase over a cardiac cycle. The negative and positive velocity values indicated antegrade and regurgitant flow, respectively, which allowed calculation of forward and regurgitant flow. Inter- and intraobserver variation of regurgitant fraction (RF) measurement was small (r = .956, standard error of the estimate [SEE] = 1.2%, n = 31; and r = .998, SEE = 0.35%, n = 10, respectively). RF determined with MR imaging agreed well with Doppler echocardiographic (n = 26) and aortographic (n = 9) grading of AR. Reproducible, quantitative, and noninvasive measurement of AR is possible with MR velocity mapping.
采用磁共振（MR）成像速度图对5名健康志愿者和26例患者（平均年龄60.3岁；范围25 - 83岁）的主动脉反流（AR）进行了定量测量。使用梯度回波序列，在1.5-T MR成像单元的层面选择方向施加速度编码双极脉冲，采集升主动脉的电影横轴图像（每个心动周期32个时相）。通过对心动周期中每个时相升主动脉面积与平均速度乘积进行积分来计算主动脉血流量。负向和正向速度值分别表示顺行血流和反流，据此可计算出正向血流和反流。观察者间和观察者内反流分数（RF）测量的差异较小（分别为r = 0.956，估计标准误差[SEE] = 1.2%，n = 31；以及r = 0.998，SEE = 0.35%，n = 10）。MR成像测定的RF与多普勒超声心动图（n = 26）和主动脉造影（n = 9）对AR的分级结果高度一致。利用MR速度图能够对AR进行可重复、定量且无创的测量。
