Organ Pose Distribution Model and an MAP Frameworl for Automated Abdominal Multi-organ Localization

摘要

Abdominal organ localization is required as an initialization step for most automated abdominal organ analysis tasks, i.e. segmentation, registration, and computer aided-diagnosis. Automated abdominal organ localization is difficult because of the large variability of organ shapes, similar appearances of different organs in images, and organs in close proximity to each other. Previous methods predicted only the organ locations, but not the full organ poses including additionally sizes and orientations. Thus they were often not accurate enough to initialize other image analysis tasks. In this work we proposed a maximum a posteriori (MAP) framework to estimate the poses of multiple abdominal organs from non-contrast CT images. A novel organ pose distribution model is proposed to model the organ poses and limit the search space. Additionally the method uses probabilistic atlases for organ shapes, and Gaussian mixture models for organ intensity profile. An MAP problem is then formulated and solved for organ poses. The method was applied for the localization of liver, left and right kidneys, spleen, and pancreas, and showed promising results, especially on liver and spleen (with mean location and orientation errors under 5.3 mm and 7 degrees respectively).