Mohiaddin R H, Kilner P J, Rees S, Longmore D B
Royal Brompton National Heart and Lung Hospital, National Heart and Lung Institute, London, England, United Kingdom.
J Am Coll Cardiol. 1993 Nov 1;22(5):1515-21. doi: 10.1016/0735-1097(93)90565-i.
Nuclear magnetic resonance (MRI) velocity mapping was used to characterize flow waveforms and to measure volume flow in the ascending and descending thoracic aorta in patients with aortic coarctation and in healthy volunteers. We present the method and discuss the relation between these measurements and aortic narrowing assessed by MRI. Finally, we compare coarctation jet velocity measured by MRI velocity mapping with that obtained from continuous wave Doppler echocardiography.
The development of a noninvasive imaging method for morphologic visualization of aortic coarctation and for measurement of its impact on blood flow is highly desirable in the preoperative and postoperative management of patients.
Magnetic resonance imaging phase-shift velocity mapping was used to measure ascending and descending aortic volume flow in 39 patients with aortic coarctation and in 12 healthy volunteers. Magnetic resonance imaging was also used for anatomic and peak jet velocity measurements. The latter were compared with those available from continuous wave Doppler study in 40% of the patients.
Whereas ascending aortic volume flow measurement did not show significant differences between the patient and healthy control groups, volume flow curves in the descending aorta did show significant differences between the two groups. Peak volume flow (mean +/- SD) was 10.6 +/- 5.3 liters/min in patients and 19.6 +/- 4.7 liters/min in control subjects (p < 0.001). Time-averaged flow was 2.5 +/- 0.9 liters/min in patients and 3.9 +/- 1.1 liters/min in control subjects (p < 0.05). The descending/ascending aorta flow ratio was 0.47 +/- 0.19 in patients and 0.64 +/- 0.08 in control subjects (p < 0.05). These variables correlate well with the degree of aortic narrowing. Peak coarctation jet velocity measured by MRI velocity mapping is comparable to that obtained from continuous wave Doppler study (r = 0.95).
We established normal ranges for volume flow in the descending aorta and demonstrated abnormalities in patients with aortic coarctation. These abnormalities are likely to be related to resistance to flow imposed by the coarctation and could represent an additional index for monitoring patients before and after intervention.
采用核磁共振（MRI）速度成像来描绘血流波形，并测量主动脉缩窄患者及健康志愿者胸主动脉升段和降段的容积流量。我们介绍该方法，并讨论这些测量值与通过MRI评估的主动脉缩窄之间的关系。最后，我们将通过MRI速度成像测量的缩窄处射流速度与连续波多普勒超声心动图获得的速度进行比较。
在主动脉缩窄患者的术前和术后管理中，非常需要一种用于主动脉缩窄形态可视化及其对血流影响测量的无创成像方法。
使用磁共振成像相移速度成像来测量39例主动脉缩窄患者和12名健康志愿者的胸主动脉升段和降段的容积流量。MRI还用于解剖结构和峰值射流速度测量。在40%的患者中，将后者与连续波多普勒研究获得的结果进行比较。
虽然患者组和健康对照组之间胸主动脉升段容积流量测量无显著差异，但降主动脉的容积流量曲线在两组间确实存在显著差异。患者的峰值容积流量（均值±标准差）为10.6±5.3升/分钟，对照组为19.6±4.7升/分钟（p<0.001）。患者的时间平均流量为2.5±0.9升/分钟，对照组为3.9±1.1升/分钟（p<0.05）。患者降主动脉/升主动脉流量比为0.47±0.19，对照组为0.64±0.08（p<0.05）。这些变量与主动脉缩窄程度密切相关。通过MRI速度成像测量的缩窄处峰值射流速度与连续波多普勒研究获得的结果相当（r = 0.95）。
我们确定了降主动脉容积流量的正常范围，并证明了主动脉缩窄患者存在异常。这些异常可能与缩窄造成的血流阻力有关，并且可能代表干预前后监测患者的一个额外指标。
