#184: Lung segmentation in chest radiographs using anatomical atlases with non-rigid registration


The National Library of Medicine (NLM) is developing a digital chest x-ray (CXR) screening system for deployment in resource constrained communities and developing countries worldwide with a focus on early detection of tuberculosis. A critical component in the computer-aided diagnosis of digital CXRs is the automatic detection of the lung regions. In this paper, we present a non-rigid registration-driven robust lung segmentation method using image retrieval-based patient specific adaptive lung models that detects lung boundaries, surpassing state-of-the-art performance. The method consists of three main stages: (i) a content-based image retrieval approach for identifying training images (with masks) most similar to the patient CXR using a partial Radon transform and Bhattacharyya shape similarity measure, (ii) creating the initial patient-specific anatomical model of lung shape using SIFT-flow for deformable registration of training masks to the patient CXR, and (iii) extracting refined lung boundaries using a graph cuts optimization approach with a customized energy function. Our average accuracy of 95:4% on the public JSRT database is the highest among published results. A similar degree of accuracy of 94:1% and 91:7% on two new CXR datasets from Montgomery County, Maryland (USA) and India, respectively, demonstrates the robustness of our lung segmentation approach.