Imaging tests of nodal disease, a, commonly used X-ray film and chest CT, its main manifestations of intrathoracic lymph node enlargement, lung parenchymal changes and pleural lesions of three major kinds, intrathoracic lymph node enlargement, common in the mediastinum of the hilar lymph node enlargement, hilar lymph node enlargement, to the two sides of the symmetry of the characteristics of the hilar lymph nodes, accounted for 90%-95%, the right hilar enlargement is generally more than the left side of the obvious, multi-group lymph node enlargement is the is the It is characterized by multiple lymph node enlargement. Second, is the lung parenchymal changes can have a variety of forms, including interstitial changes, alveolar changes, tachyphylaxis, intrapulmonary granulomatous lesions, and fibrous scarring lesions. Third, pleural lesions, in the past, it is believed that nodal disease generally rarely invades the pleura, less than 1% of pleural effusion, but now confirmed that nodal disease combined with pleurisy is not uncommon, in recent years, the statistics of effusion can be up to 10%, but generally does not cause a large amount of pleural effusion. Currently, the international classification of intrathoracic nodal disease according to X-ray performance is divided into five stages, stage 0 is the lung X-ray examination is normal. Stage 2 is bilateral hilar lymph node enlargement with concomitant lobar lesions seen in 30% to 50% of patients, and stage 3 is diffuse lung lesions without lymph node enlargement. Stage IV is extensive pulmonary fibrosis, alveoli, and pulmonary cysts, and this stage has a very poor prognosis.