Mediastinum is a structure that lies in the central thoracic compartment and is laterally bounded by the lungs. The mediastinum structures in chest radiographic images pose inter-subject variability along with irregular and unclear boundaries. In addition, the disease manifestations are reported to cause structural alterations in the region. Analysis of the magnitude of these changes using image processing techniques helps in the characterization of the disease. In this work, the mediastinum structural changes for the differentiation of normal and tuberculosis conditions using chest radiographic images are analyzed. The differential diagnostics of bacterial and viral pneumonia are also performed. The details of segmentation methods, classification approaches, significant results, and contributions would be discussed in this seminar.