Bijar Ahmad, Rohan Pierre-Yves, Perrier Pascal, Payan Yohan
Univ. Grenoble Alpes, TIMC-IMAG, 38000, Grenoble, France.
CNRS, TIMC-IMAG, 38000, Grenoble, France.
Ann Biomed Eng. 2016 Jan;44(1):16-34. doi: 10.1007/s10439-015-1497-y. Epub 2015 Nov 17.
Generation of subject-specific 3D finite element (FE) models requires the processing of numerous medical images in order to precisely extract geometrical information about subject-specific anatomy. This processing remains extremely challenging. To overcome this difficulty, we present an automatic atlas-based method that generates subject-specific FE meshes via a 3D registration guided by Magnetic Resonance images. The method extracts a 3D transformation by registering the atlas' volume image to the subject's one, and establishes a one-to-one correspondence between the two volumes. The 3D transformation field deforms the atlas' mesh to generate the subject-specific FE mesh. To preserve the quality of the subject-specific mesh, a diffeomorphic non-rigid registration based on B-spline free-form deformations is used, which guarantees a non-folding and one-to-one transformation. Two evaluations of the method are provided. First, a publicly available CT-database is used to assess the capability to accurately capture the complexity of each subject-specific Lung's geometry. Second, FE tongue meshes are generated for two healthy volunteers and two patients suffering from tongue cancer using MR images. It is shown that the method generates an appropriate representation of the subject-specific geometry while preserving the quality of the FE meshes for subsequent FE analysis. To demonstrate the importance of our method in a clinical context, a subject-specific mesh is used to simulate tongue's biomechanical response to the activation of an important tongue muscle, before and after cancer surgery.
生成特定个体的三维有限元（FE）模型需要处理大量医学图像，以便精确提取特定个体解剖结构的几何信息。这种处理仍然极具挑战性。为克服这一困难，我们提出一种基于图谱的自动方法，该方法通过磁共振图像引导的三维配准生成特定个体的有限元网格。该方法通过将图谱的体积图像与个体的体积图像进行配准来提取三维变换，并在两个体积之间建立一一对应关系。三维变换场使图谱的网格变形，以生成特定个体的有限元网格。为了保持特定个体网格的质量，使用了基于B样条自由形式变形的微分同胚非刚性配准，这保证了非折叠和一一变换。对该方法进行了两项评估。首先，使用一个公开可用的CT数据库来评估准确捕捉每个特定个体肺部几何复杂性的能力。其次，使用磁共振图像为两名健康志愿者和两名舌癌患者生成有限元舌网格。结果表明，该方法在保留有限元网格质量以进行后续有限元分析的同时，生成了特定个体几何结构的合适表示。为了在临床背景下证明我们方法的重要性，在癌症手术前后，使用特定个体的网格来模拟舌头对一块重要舌肌激活的生物力学反应。
