Magnetic resonance imaging of cardiacvascular function

我们的实验室应用了一种名为Dense的高功率磁共振技术来详细成像心壁和颈动脉壁的运动。Dense代表用模拟回声进行位移编码，是我们实验室的首创。我们今年成功地开发了用于心脏和血管壁应变和运动映射的扫描方案和数据处理软件，并在正常志愿者和患者身上进行了测试。这项研究的一个应用是测量舒张期早期和中期心壁的顺应性或硬度，这是心脏腔如何在舒张期迅速充盈到容量的关键因素。我们还利用这项技术精确地测量了由于心肌内脉动血压和冠脉血流相互作用而导致的心壁组织体积的波动。这些发现发表在《医学磁共振》杂志上，并在会议上发表。 我们的实验室还观察到，当将血池造影剂注入动物体内时，心脏的自旋回波磁共振成像中出现了一个新现象--图像强度与扫描仪磁场方向的关系。我们发现了这一现象背后的机制，并在大鼠模型中的初步数据表明，这是一种非常有效的方法来绘制心脏跳动中的毛细血管结构，并由此推断肌肉纤维结构。这可能是对体内微血管结构进行成像的最有效方法。这一发现也发表在《医学磁共振》杂志上。

Our lab has applied a high-power MRI technique called DENSE to image heart wall and carotid artery wall motion in detail. DENSE stands for Displacement ENcoding with Stimulated Echo and is pioneered in our lab. We successfully developed this year the scan protocol and data processing software for heart and blood vessel wall strain and motion mapping, and tested them in normal volunteers and patients. One application of this development is to measure the compliance or stiffness of the heart wall in early and mid diastole, which is a key factor in how the heart chambers rapidly fills to volume in diastole. We also used this technique to accurately measure the fluctuation of tissue volume in the heart wall due from the interaction between the oscillating intramyocardial blood pressure and coronary blood flow. These findings are published in the journal Magnetic Resonance in Medicine and presented in conferences. Our lab also observed a new phenomenon in spin-echo MRI of the heart when a blood-pool contrast agent is infused into the animal - a dependence of the image intensity on the direction of the scanner's magnetic field. We found the mechanism behind the phenomenon and with preliminary data in a rat model showed that it is a very effective way to map the capillary structure, and by inference muscle fiber structure, in a beating heart. This is probably the most effective way of imaging microvascular structure in vivo. This finding is also published in the journal Magnetic Resonance in Medicine.