Medical Electronics Division, Institute of Electronics, Lodz University of Technology, Lodz, Poland.
PLoS One. 2014 Apr 16;9(4):e93689. doi: 10.1371/journal.pone.0093689. eCollection 2014.
With the development of medical imaging modalities and image processing algorithms, there arises a need for methods of their comprehensive quantitative evaluation. In particular, this concerns the algorithms for vessel tracking and segmentation in magnetic resonance angiography images. The problem can be approached by using synthetic images, where true geometry of vessels is known. This paper presents a framework for computer modeling of MRA imaging and the results of its validation. A new model incorporates blood flow simulation within MR signal computation kernel. The proposed solution is unique, especially with respect to the interface between flow and image formation processes. Furthermore it utilizes the concept of particle tracing. The particles reflect the flow of fluid they are immersed in and they are assigned magnetization vectors with temporal evolution controlled by MR physics. Such an approach ensures flexibility as the designed simulator is able to reconstruct flow profiles of any type. The proposed model is validated in a series of experiments with physical and digital flow phantoms. The synthesized 3D images contain various features (including artifacts) characteristic for the time-of-flight protocol and exhibit remarkable correlation with the data acquired in a real MR scanner. The obtained results support the primary goal of the conducted research, i.e. establishing a reference technique for a quantified validation of MR angiography image processing algorithms.
随着医学成像模式和图像处理算法的发展，需要对其进行全面的定量评估方法。特别是，这涉及到磁共振血管造影图像中的血管跟踪和分割算法。可以通过使用真实血管几何形状已知的合成图像来解决此问题。本文提出了一种用于 MRA 成像的计算机建模框架及其验证结果。一个新的模型将血流模拟纳入到 MR 信号计算内核中。所提出的解决方案是独特的，特别是在流动和图像形成过程之间的接口方面。此外，它利用了粒子追踪的概念。粒子反映了它们所处的流体的流动，并且被赋予了随 MR 物理控制的时间演化的磁化矢量。这种方法确保了灵活性，因为设计的模拟器能够重建任何类型的流动轮廓。该模型在一系列物理和数字流量体模实验中得到了验证。合成的 3D 图像包含各种特征（包括伪影），这些特征是针对飞行时间协议的，并且与在实际的磁共振扫描仪中获得的数据具有显著的相关性。所获得的结果支持了所进行的研究的主要目标，即建立一种参考技术，用于对磁共振血管造影图像处理算法进行定量验证。
