Lung CT can see enlarged lymph nodes, and mediastinal lymph node enlargement can be seen by chest enhancement CT. Lung CT mainly looks for lesions on both sides of the lungs, and can also detect organ lesions within the mediastinum, including the aorta, heart, superior vena cava, and also the ribs, thoracic vertebrae, and sternum, etc. Within a normal lung CT, there is often no imaging of enlarged lymph nodes. Lymph node enlargement within the mediastinum can be detected on lung CT when it is due to inflammation, lung cancer, mediastinal masses, esophageal cancer, and lymphoma. When abnormally enlarged lymph nodes in the mediastinum are detected, chest enhancement CT, tumor markers, and blood tests are often needed to help determine the cause of the enlarged lymph nodes, and if there is no clear causative factor, pet-CT and thoracoscopic mediastinal lymph node biopsy may be needed to help determine the cause of the enlarged lymph nodes.