A method for segmenting an anatomical structure having portions occluded in a digital image wherein the digital image is produced by a projection-based medical imaging modality. The method includes the steps of: outlining an unoccluded portion of the anatomical structure in a training image; augmenting the occluded portion of the anatomical structure according to a pre-determined atlas of the anatomical structure; generating an augmented training example using the outlined and augmented portions; repeating the steps of outlining, augmenting, and generating for a plurality of training images to train a statistical model of the structure; accessing the digital image; and segmenting the anatomical structure in the accessed digital image according to the statistical model.