Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, 40402, Taiwan, Republic of China.
Phys Med Biol. 2010 Jul 21;55(14):4153-68. doi: 10.1088/0031-9155/55/14/013. Epub 2010 Jul 5.
This study presents a finite element-based computational model to simulate the three-dimensional deformation of a breast and fibroglandular tissues under compression. The simulation was based on 3D MR images of the breast, and craniocaudal and mediolateral oblique compression, as used in mammography, was applied. The geometry of the whole breast and the segmented fibroglandular tissues within the breast were reconstructed using triangular meshes by using the Avizo 6.0 software package. Due to the large deformation in breast compression, a finite element model was used to simulate the nonlinear elastic tissue deformation under compression, using the MSC.Marc software package. The model was tested in four cases. The results showed a higher displacement along the compression direction compared to the other two directions. The compressed breast thickness in these four cases at a compression ratio of 60% was in the range of 5-7 cm, which is a typical range of thickness in mammography. The projection of the fibroglandular tissue mesh at a compression ratio of 60% was compared to the corresponding mammograms of two women, and they demonstrated spatially matched distributions. However, since the compression was based on magnetic resonance imaging (MRI), which has much coarser spatial resolution than the in-plane resolution of mammography, this method is unlikely to generate a synthetic mammogram close to the clinical quality. Whether this model may be used to understand the technical factors that may impact the variations in breast density needs further investigation. Since this method can be applied to simulate compression of the breast at different views and different compression levels, another possible application is to provide a tool for comparing breast images acquired using different imaging modalities--such as MRI, mammography, whole breast ultrasound and molecular imaging--that are performed using different body positions and under different compression conditions.
本研究提出了一种基于有限元的计算模型，用于模拟乳房和纤维腺体组织在压缩下的三维变形。该模拟基于乳房的三维 MR 图像，并应用了乳腺摄影中使用的头尾向和内外斜向压缩。使用 Avizo 6.0 软件包，通过三角形网格重建了整个乳房的几何形状和乳房内分割的纤维腺体组织。由于乳房压缩时的大变形，使用 MSC.Marc 软件包使用有限元模型模拟了压缩下的非线性弹性组织变形。该模型在四种情况下进行了测试。结果表明，在压缩方向上的位移高于其他两个方向。在压缩比为 60%的情况下，这四种情况下的压缩乳房厚度在 5-7 厘米之间，这是乳腺摄影中典型的厚度范围。在压缩比为 60%时，纤维腺体组织网格的投影与两名女性的相应乳腺 X 线照片进行了比较，它们显示出空间匹配的分布。然而，由于压缩基于磁共振成像（MRI），其空间分辨率比乳腺 X 线摄影的平面分辨率要粗糙得多，因此这种方法不太可能生成接近临床质量的合成乳腺 X 线照片。该模型是否可用于了解可能影响乳房密度变化的技术因素需要进一步研究。由于该方法可用于模拟不同视图和不同压缩水平下的乳房压缩，因此另一个可能的应用是提供一种工具，用于比较使用不同成像方式（如 MRI、乳腺 X 线摄影、全乳房超声和分子成像）获得的乳房图像，这些方式使用不同的体位并在不同的压缩条件下进行。
