Hardy C J, Bolster B D, McVeigh E R, Adams W J, Zerhouni E A
GE Corporate Research and Development Center, Schenectady, New York 12301.
Magn Reson Med. 1994 May;31(5):513-20. doi: 10.1002/mrm.1910310507.
A technique is presented for rapidly and noninvasively determining aortic distensibility, by NMR measurement of wave velocity in the aorta. A two-dimensional NMR selective-excitation pulse is used to repeatedly excite a cylinder of magnetization in the aorta, with magnetization read out along the cylinder axis each time. A toggled bipolar flow-encoding pulse is applied prior to readout, to produce a non-dimensional phase-contrast flow image. Cardiac gating and data interleaving are employed to improve the effective time resolution to 2 ms. Wave velocities are determined from the slope of the leading edge of flow measured on the resulting M-mode velocity image. The technique is sensitive over a range of distensibilities from 10(-6) to 10(-3) m s2/kg. The average value in the descending thoracic aorta in seven normal subjects was found to be 4.8 x 10(-5) m s2/kg, with a significant inverse correlation with age.
本文介绍了一种通过核磁共振测量主动脉波速来快速、无创地测定主动脉扩张性的技术。使用二维核磁共振选择性激发脉冲反复激发主动脉中的一个磁化圆柱体，每次沿圆柱体轴读出磁化强度。在读出之前施加一个切换双极流动编码脉冲，以产生无量纲的相位对比流动图像。采用心脏门控和数据交织技术将有效时间分辨率提高到2毫秒。从所得M型速度图像上测量的血流前沿斜率确定波速。该技术在10^(-6)至10^(-3) m·s²/kg的扩张性范围内敏感。在7名正常受试者的降主动脉中，平均值为4.8×10^(-5) m·s²/kg，与年龄呈显著负相关。
