Wise Richard G, Al-Shafei Ahmad I M, Carpenter T Adrian, Hall Laurance D, Huang Christopher L-H
Department of Human Anatomy and Genetics, University of Oxford, Oxford, UK.
J Magn Reson Imaging. 2005 Nov;22(5):614-27. doi: 10.1002/jmri.20423.
To measure cardiac blood flow patterns and ventricular wall velocities through the cardiac cycle in anesthetized Wistar Kyoto (WKY) rats.
A gradient-echo cine pulse sequence incorporating pulsed field gradients (PFGs) provided phase contrast (PC) motion encoding. We achieved a range of velocity sensitivity that was sufficient to measure simultaneously the large flow velocities within the cardiac chambers and aortic outflow tract (up to 70 cm s(-1) during systole), and the comparatively small velocities of the cardiac wall (0-3 cm s(-1)). A scheme of sparsely sampling q-space combined with a probability-based method of velocity calculation permitted such measurements along three orthogonal axes, and yielded velocity vector maps in all four chambers of the heart and the aorta, in both longitudinal and transverse sections, for up to 12 time-points in the cardiac cycle.
Left ventricular systole was associated with a symmetrical laminar flow pattern along the cardiac axis, with no appearance of turbulence. In contrast, blood showed a swirling motion within the right ventricle (RV) in the region of the pulmonary outflow tract. During left ventricular diastole a plume of blood entered the left ventricle (LV) from the left atrium. The ventricular flow patterns could also be correlated with measurements of left ventricular wall motion. The greatest velocities of the ventricular walls occurred in the transverse cardiac plane and were maximal during diastolic refilling. The cardiac wall motion in the longitudinal axis demonstrated a caudal-apical movement that may also contribute to diastolic refilling.
The successful measurements of blood and myocardial velocity during normal myocardial function may be extended to quantify pathological cardiac changes in animal models of human cardiac disease.
测量麻醉状态下的Wistar Kyoto（WKY）大鼠心动周期中的心脏血流模式和心室壁速度。
采用结合脉冲场梯度（PFG）的梯度回波电影脉冲序列提供相位对比（PC）运动编码。我们实现了一系列速度灵敏度，足以同时测量心腔内和主动脉流出道内的大流速（收缩期可达70 cm s⁻¹）以及相对较小的心室壁速度（0 - 3 cm s⁻¹）。一种稀疏采样q空间的方案与基于概率的速度计算方法相结合，允许沿三个正交轴进行此类测量，并在心动周期的多达12个时间点上，在心脏的所有四个腔室和主动脉的纵向和横向截面中生成速度矢量图。
左心室收缩期与沿心脏轴的对称层流模式相关，无湍流出现。相比之下，在肺流出道区域，右心室内的血液呈现漩涡运动。在左心室舒张期，一股血流从左心房进入左心室。心室血流模式也可与左心室壁运动的测量相关联。心室壁的最大速度出现在心脏横向平面，并且在舒张期充盈时最大。心脏纵轴上的壁运动表现为尾端 - 心尖运动，这也可能有助于舒张期充盈。
在正常心肌功能期间成功测量血液和心肌速度，可能会扩展到对人类心脏病动物模型中的病理性心脏变化进行量化。
