3D Analysis of MR-imaged Articular Cartilage

DESCRIPTION (provided by applicant): Osteoarthritis and articular cartilage injuries are very common, typically causing pain, swelling and reduced mobility leading to functional impairment. The treatment cost for patients suffering from these conditions are massive with an estimated annual economic cost of $65 billion in the US alone. Magnetic resonance imaging facilitates non-invasive imaging of articular cartilage in vivo. However, manual analysis is tedious, inaccurate, and irreproducible and no computer-aided tool is commercially available to analyze high-resolution 3-D MR cartilage image data. This proposal is for development and feasibility assessment of quantitative analysis of articular cartilage in highly congruent joints (knee, hip, ankle) from 3-D magnetic resonance images. The Phase I proposal will demonstrate that identification (segmentation) of the cartilage surfaces can be accomplished highly automatically and with subvoxel accuracy in the most difficult-to-segment region of the joint contact area. The main innovation of the proposed approach is that the multiple surfaces of adjoining bones and cartilages will be segmented simultaneously in 3-D rather than independently border-by-border and slice-by-slice in 2-D, thus taking advantage of 3-D contextual information with an expected improvement in 3-D segmentation performance. The specific aims of this Phase-l proposal are to: 1) Develop a method for simultaneous multi-surface detection of cartilage and bone surfaces in volumetric high-resolution MR images. 2) Develop a method for automated initialization of such multi-surface segmentation. 3) Assess segmentation errors and demonstrate subvoxel accuracy of the developed methods for cartilage segmentation and cartilage morphology assessment in comparison with existing independent standards. Once feasibility is demonstrated in the joint contact region, the future Phase II will develop methods for comprehensive analysis of cartilage morphology and cartilage tissue characterization in the entire joint. Therefore, the goal of the continuing Phase II research will be to build and validate a prototype system for quantitative cartilage analysis that will be utilized by orthopedic clinicians treating osteoarthritis, orthopedic surgeons, musculoskeletal radiologists, and researchers for epidemiologic and pharmacologic studies, as well as by MR scanner manufacturers.