National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Magn Reson Med. 2012 Apr;67(4):1013-21. doi: 10.1002/mrm.23078. Epub 2011 Aug 19.
In magnetic resonance imaging-guided cardiovascular interventional procedures, it is valuable to be able to visualize blood flow immediately and interactively in selected regions. In particular, it is useful to assess normal or pathological communications between specific heart chambers and vessels. Phase-contrast velocity mapping is not suitable for this purpose as it requires too much data and is not capable of determining directly if blood originating in one location travels to a nearby location. This article presents a novel flow visualization method called virtual dye angiography that enables visualization of blood flow analogous to selective catheter angiography. The method uses two-dimensional radio frequency pulses to achieve interactive, intermittent, targeted saturation of a localized region of the blood pool. The flow of the saturated spins is observed directly on real-time images or, in an enhanced manner, using ECG synchronized background subtraction. The modular nature of the technique allows for easy and seamless integration into a real-time, interactive imaging system with minimal overhead. We present initial results in animals and in a healthy human volunteer.
在磁共振成像引导的心血管介入治疗中，能够即时可视化选定区域的血流并进行交互操作是非常有价值的。特别是，评估特定心脏腔室和血管之间的正常或病理连通非常有用。相位对比速度映射不适合此目的，因为它需要太多的数据，并且不能直接确定源自一个位置的血液是否流向附近的位置。本文提出了一种称为虚拟染料血管造影的新的血流可视化方法，它可以模拟选择性导管血管造影来可视化血流。该方法使用二维射频脉冲实现对血液池局部区域的交互式、间歇性、靶向饱和。通过实时图像或使用 ECG 同步背景减除以增强方式直接观察饱和自旋的流动。该技术的模块化性质允许轻松无缝地集成到具有最小开销的实时交互式成像系统中。我们在动物和健康的人类志愿者中展示了初步结果。
