Carballido-Gamio Julio, Bauer Jan, Lee Keh-Yang, Krause Stefanie, Majumdar Sharmila
Musculo-skeletal and Quantitative Imaging Research Group, University of California, San Francisco, CA, USA.
Conf Proc IEEE Eng Med Biol Soc. 2005;2005:3043-6. doi: 10.1109/IEMBS.2005.1617116.
A common manifestation of osteoarthritis (OA) of the knee is the morphological degeneration of articular cartilage. In vivo magnetic resonance imaging (MRI) offers the potential to visualize and analyze quantitatively morphology such as cartilage thickness and volume. The purpose of this work was the development of new image processing techniques and application of existing ones for the intra and inter-subject quantitative analysis of cartilage of the knee. The process consists of MRI acquisition, cartilage segmentation, shape-based interpolation of segmented cartilage, segmentation of bone, volume registration based on bone structures, analysis, and visualization. The process is semi-automatic, the segmentation which is based on Bezier splines and edge detection requires interaction. Different shape interpolation methods were compared. The registration is based on shape matching and can be rigid-body and elastic. The analysis comprises cartilage volume and thickness calculations. The visualization allows the depiction of cartilage thickness maps overlaid on MR images or in three dimensions (3D). The cartilage segmentation and shape-based interpolation techniques were validated visually and based on the volumetric measurements of images of porcine knees which cartilage volume were directly measured using a saline displacement method. The registration technique was validated visually and using manual landmark registration.
膝关节骨关节炎（OA）的一个常见表现是关节软骨的形态学退变。活体磁共振成像（MRI）能够对诸如软骨厚度和体积等形态进行可视化和定量分析。本研究的目的是开发新的图像处理技术，并应用现有技术对膝关节软骨进行受试者内和受试者间的定量分析。该过程包括MRI采集、软骨分割、基于形状的分割软骨插值、骨分割、基于骨结构的体积配准、分析和可视化。该过程是半自动的，基于贝塞尔样条和边缘检测的分割需要交互操作。比较了不同的形状插值方法。配准基于形状匹配，可以是刚体配准和弹性配准。分析包括软骨体积和厚度计算。可视化可以在MR图像上或三维（3D）中描绘软骨厚度图。通过视觉验证以及基于猪膝关节图像的体积测量（使用盐水置换法直接测量软骨体积）对软骨分割和基于形状的插值技术进行了验证。通过视觉验证以及使用手动地标配准对配准技术进行了验证。
