The lung is a unique interface between the antigen and the circulating blood volume. It is submitted to extrinsic/intrinsic challenges and is particularly vulnerable to circulating insulting agents. It is a site of intense immune surveillance, allowing antigen sampling to expand the immunologic repertoire through lymphocyte recirculation. In addition, local inflammatory reactions to antigens are generated. Imaging has an important role in diagnosis of patients with immunologic lung diseases. This group includes autoimmune lung diseases. There are many advantages of plain chest radiography but also significant limitations. It was a revolution in imaging of lung diseases with Computed Tomography (CT), being high resolution an important help in pulmonary interstitium study. This technique has a higher diagnostic accuracy than the conventional chest X-ray both in the detection and the diagnosis of lung diseases, such as autoimmune lung diseases.