Hemoptysis patients line CT examination may not be able to find out, for some of the diagnosis of the disease has a certain significance, such as: because of bronchiectasis caused by hemoptysis, usually can be detected by CT examination; if because of tuberculosis caused by hemoptysis, CT examination combined with tuberculin experiments and so on to help clarify the diagnosis; but if because of hematological diseases, rheumatic diseases, endocrine diseases caused by hemoptysis generally CT However, if the hemoptysis is caused by hematological diseases, rheumatic diseases, endocrine diseases, etc., CT examination is usually unable to detect it. There are many causes of hemoptysis, including respiratory diseases, such as bronchodilatation, bronchitis, lung cancer, tuberculosis, pulmonary embolism, etc.; cardiovascular diseases, such as mitral stenosis, arterial catheterization, etc.; hematological diseases, such as leukemia, aplastic anemia, etc.; and rheumatic and endocrine diseases, such as systemic lupus erythematosus, endometriosis, etc. CT examination is helpful for some diseases to diagnose hemoptysis, but CT examination is generally unable to detect hemoptysis if it is due to hematological diseases, rheumatic diseases and endocrine diseases. CT examination is meaningful for hemoptysis caused by some diseases, such as bronchitis, bronchiectasis, lung cancer, tuberculosis and so on. But for some diseases, such as leukemia, aplastic anemia, systemic lupus erythematosus, endometriosis and so on, CT examination can not be detected. Patients with hemoptysis can consult a physician to determine whether CT examination is necessary.