Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA.
J Cardiovasc Magn Reson. 2011 Dec 21;13(1):81. doi: 10.1186/1532-429X-13-81.
Stiffening of the arteries results in increased pulse-wave velocity (PWV), the propagation velocity of the blood. Elevated aortic PWV has been shown to correlate with aging and atherosclerotic alterations. We extended a previous non-triggered projection-based cardiovascular MR method and demonstrate its feasibility by mapping the PWV of the aortic arch, thoraco-abdominal aorta and iliofemoral arteries in a cohort of healthy adults.
The proposed method "simultaneously" excites and collects a series of velocity-encoded projections at two arterial segments to estimate the wave-front velocity, which inherently probes the high-frequency component of the dynamic vessel wall modulus in response to oscillatory pressure waves. The regional PWVs were quantified in a small pilot study in healthy subjects (N = 10, age range 23 to 68 yrs) at 3T.
The projection-based method successfully time-resolved regional PWVs for 8-10 cardiac cycles without gating and demonstrated the feasibility of monitoring beat-to-beat changes in PWV resulting from heart rate irregularities. For dual-slice excitation the aliasing was negligible and did not interfere with PWV quantification. The aortic arch and thoracoabdominal aorta PWV were positively correlated with age (p < 0.05), consistent with previous reports. On the other hand, the PWV of the iliofemoral arteries showed decreasing trend with age, which has been associated with the weakening of muscular arteries, a natural aging process.
The PWV map of the arterial tree from ascending aorta to femoral arteries may provide additional insight into pathophysiology of vascular aging and atherosclerosis.
动脉僵硬会导致脉搏波速度（PWV）增加，即血液的传播速度。已经证明，主动脉 PWV 升高与衰老和动脉粥样硬化改变相关。我们扩展了以前的基于非触发投影的心血管磁共振方法，并通过在一组健康成年人中绘制升主动脉、胸主动脉和股髂动脉的 PWV，证明了其可行性。
所提出的方法“同时”激发和采集两个动脉段的一系列速度编码投影，以估计波前速度，该速度固有地探测到响应脉动压力波的动态血管壁模量的高频分量。在一项小型健康受试者的初步研究（N=10，年龄范围 23 至 68 岁）中，在 3T 上对区域性 PWV 进行了定量。
基于投影的方法成功地无门控地对 8-10 个心动周期进行了时间分辨的区域性 PWV，并且证明了监测由于心率不规则导致的 PWV 逐搏变化的可行性。对于双片激发，混叠可以忽略不计，并且不会干扰 PWV 定量。升主动脉和胸主动脉 PWV 与年龄呈正相关（p<0.05），与先前的报告一致。另一方面，股髂动脉的 PWV 随着年龄的增长呈下降趋势，这与肌肉动脉的减弱有关，是一种自然衰老过程。
从升主动脉到股髂动脉的动脉树的 PWV 图可能为血管老化和动脉粥样硬化的病理生理学提供更多的见解。
