Chest X-ray is commonly ordered to look for a cause of chest pain. While chest pain can be due to many conditions ranging from benign heart burn all the way to deadly conditions such as heart attack and aortic dissection. A chest X-ray can be done portably in the emergency department or in your hospital room. The best quality chest X-rays are done in the radiology department.
Chest X-ray is a start as it can diagnose some important conditions such as pneumonia, pneumothorax, cancers, heart failure and edema, pleural effusion, and fractures. Many others like pulmonary embolism, aortic dissection and heart attack can not be diagnosed and are invisible on X-ray. A normal chest X-ray therefore does not diagnose many important and deadly conditions.
A chest X-ray is best interpreted in the context of the patient’s symptoms. For example, a white area at the bottom of the lung is most likely pneumonia in the setting of cough and fever, while it may be a tumor if the patient has had chronic symptoms and is a smoker. In other cases, a specific diagnosis can be made like when there is a pneumothorax. That is, when there is air between the chest wall and lung which causes collapse.
A fracture of a rib or other bones in the chest can sometimes be made. Fluid between the lung and chest wall called a pleural effusion can also be diagnosed. Heart failure can be diagnosed when there is a large heart, edema in the lung and pleural effusion. This is often followed by an ultrasound of the heart called an echocardiogram. A cancer can sometimes be made when a mass is seen in the chest or there are enlarged lymph nodes.
Your doctor will take a detailed history, perform a physical exam, do lab testing and order additional tests if needed. A chest X-ray is just a start and may provide a diagnosis but certainly does not rule out an abnormality. Sometimes big abnormalities can not be seen on a chest X-ray. Your doctor will therefore have to pursue further testing based on his clinical suspicion.