Modeling Lung Architecture in the XCAT Series of Phantoms: Physiologically Based Airways, Arteries and Veins.
Modeling Lung Architecture in the XCAT Series of Phantoms: Physiologically Based Airways, Arteries and Veins.
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DOI：
10.1109/tmi.2017.2769640
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发表时间：
2018-03
影响因子：
10.6
通讯作者：
Samei E
中科院分区：
文献类型：
--
作者：
Abadi E;Segars WP;Sturgeon GM;Roos JE;Ravin CE;Samei E
这项研究的目的是扩展扩展心脏躯干(XCAT)系列计算模型，以包括详细的肺结构，包括呼吸道和肺血管系统。本研究使用了11个不同解剖结构的xCAT模体。先前在每个xCAT模型中定义了肺叶和呼吸道、肺动静脉的初始分支。使用基于解剖学的容量填充分支算法，将这些模型从呼吸道和血管的初始分支扩展到末梢分支的水平。该算法使用圆柱形模型，通过基于顺序的解剖学测量估计直径，分别且迭代地生长呼吸道和血管分支，而不是彼此相交。将延长的分支的几何特征与文献解剖学数值进行比较，以对模型进行定量评估。这些特征包括分枝角度、长径比、子代直径比、不对称分枝模式、直径和长度比。然后使用xCAT模体来模拟CT图像，以将其与原始模体图像进行定性比较。所提出的生长模型为xCAT模体提供了46369±12521条气管、44737±11773条动脉和39819±9988条静脉。此外，生长模型被证明产生了不对称的气道、动脉和静脉网络，其几何属性接近于形态计量学和基于模型的研究。与原始模型相比，模拟模型的CT图像被认为更逼真，包括更多的呼吸道和肺血管。未来的工作将寻求将不同种类的实质背景添加到xCAT肺中，使模型更能代表人体解剖学，为使用xCAT模型作为虚拟评估当前和新兴医学成像技术的工具铺平道路。
The purpose of this study was to extend the Extended Cardiac-Torso (XCAT) series of computational phantoms to include a detailed lung architecture including airways and pulmonary vasculature. Eleven XCAT phantoms of varying anatomy were used in this study. The lung lobes and initial branches of the airways, pulmonary arteries and veins were previously defined in each XCAT model. These models were extended from the initial branches of the airways and vessels to the level of terminal branches using an anatomically-based volume-filling branching algorithm. This algorithm grew the airway and vasculature branches separately and iteratively without intersecting each other using cylindrical models with diameters estimated by order-based anatomical measurements. Geometrical features of the extended branches were compared with literature anatomy values to quantitatively evaluate the models. These features include branching angle, length to diameter ratio, daughter to parent diameter ratio, asymmetrical branching pattern, diameter, and length ratios. The XCAT phantoms were then used to simulate CT images to qualitatively compare them with the original phantom images. The proposed growth model produced 46369±12521 airways, 44737±11773 arteries, and 39819±9988 veins to the XCAT phantoms. Furthermore, the growth model was shown to produce asymmetrical airway, artery, and vein networks with geometrical attributes close to morphometry and model based studies. The simulated CT images of the phantoms were judged to be more realistic, including more airways and pulmonary vessels compared to the original phantoms. Future work will seek to add a heterogeneous parenchymal background into the XCAT lungs to make the phantoms even more representative of human anatomy, paving the way towards the use of XCAT models as a tool to virtually evaluate the current and emerging medical imaging technologies.