Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USA.
Phys Med Biol. 2011 Sep 21;56(18):5845-64. doi: 10.1088/0031-9155/56/18/005. Epub 2011 Aug 18.
Cardiovascular disease in general and coronary artery disease (CAD) in particular, are the leading cause of death worldwide. They are principally diagnosed using either invasive percutaneous transluminal coronary angiograms or non-invasive computed tomography angiograms (CTA). Minimally invasive therapies for CAD such as angioplasty and stenting are rendered under fluoroscopic guidance. Both invasive and non-invasive imaging modalities employ ionizing radiation and there is concern for deterministic and stochastic effects of radiation. Accurate simulation to optimize image quality with minimal radiation dose requires detailed, gender-specific anthropomorphic phantoms with anatomically correct heart and associated vasculature. Such phantoms are currently unavailable. This paper describes an open source heart phantom development platform based on a graphical user interface. Using this platform, we have developed seven high-resolution cardiac/coronary artery phantoms for imaging and dosimetry from seven high-quality CTA datasets. To extract a phantom from a coronary CTA, the relationship between the intensity distribution of the myocardium, the ventricles and the coronary arteries is identified via histogram analysis of the CTA images. By further refining the segmentation using anatomy-specific criteria such as vesselness, connectivity criteria required by the coronary tree and image operations such as active contours, we are able to capture excellent detail within our phantoms. For example, in one of the female heart phantoms, as many as 100 coronary artery branches could be identified. Triangular meshes are fitted to segmented high-resolution CTA data. We have also developed a visualization tool for adding stenotic lesions to the coronaries. The male and female heart phantoms generated so far have been cross-registered and entered in the mesh-based Virtual Family of phantoms with matched age/gender information. Any phantom in this family, along with user-defined stenoses, can be used to obtain clinically realistic projection images with the Monte Carlo code penMesh for optimizing imaging and dosimetry.
总的来说，心血管疾病，特别是冠状动脉疾病（CAD），是全球范围内的主要死亡原因。它们主要通过有创的经皮腔内冠状动脉血管成形术或无创的计算机断层血管造影（CTA）进行诊断。CAD 的微创治疗，如血管成形术和支架置入术，是在荧光透视引导下进行的。有创和无创成像方式都采用电离辐射，人们担心辐射会产生确定性和随机性效应。为了在最小辐射剂量下优化图像质量，需要进行精确的模拟，这需要具有解剖学正确的心脏和相关血管的详细、性别特异性的人体模型。目前，这种模型还没有。本文描述了一种基于图形用户界面的开源心脏模型开发平台。使用这个平台，我们已经从七个高质量的 CTA 数据集开发了七个用于成像和剂量学的高分辨率心脏/冠状动脉模型。要从冠状动脉 CTA 中提取模型，需要通过 CTA 图像的直方图分析识别心肌、心室和冠状动脉的强度分布之间的关系。通过进一步使用解剖学特定标准（如血管化、冠状动脉树所需的连通性标准以及图像操作（如活动轮廓）来细化分割，我们能够在模型中捕捉到出色的细节。例如，在一个女性心脏模型中，多达 100 个冠状动脉分支可以被识别。三角网格被拟合到分割后的高分辨率 CTA 数据上。我们还开发了一种向冠状动脉添加狭窄病变的可视化工具。迄今为止生成的男性和女性心脏模型已经进行了交叉注册，并与具有匹配年龄/性别信息的基于网格的虚拟模型家族进行了匹配。这个家族中的任何一个模型，以及用户定义的狭窄，可以与 Monte Carlo 代码 penMesh 一起用于获取具有临床现实性的投影图像，以优化成像和剂量学。
