What is a Chest X-ray?
A chest x-ray is a diagnostic procedure that produces images of the inside of the chest using x-ray radiation.
During this test, an x-ray machine sends a small burst of radiation to the part being examined and records an image on a photographic film placed on the other side of the patient. Bones absorb most of the x-rays and appear white in the image, while soft tissues allow x-rays to pass through them and appear dark.
On a chest x-ray, the ribs and the spine absorb maximum radiations and appear white, whereas the lung tissue and the air in the lungs appear black.
A chest x-ray typically checks for abnormalities in the lungs, heart, large blood vessels and bones in the chest. It is a quick and easy procedure that is used in the emergency diagnosis of certain conditions.
The chest x-ray can be performed in the following projections:
- PA view- posteroanterior (PA) view
- AP view- anteroposterior (AP) erect view
PA view is the standard position for a chest x-ray. In this, the x-ray radiation is passed from the posterior (back) to the anterior (front) of the chest. It is an excellent test to image the lungs, heart and mediastinum, but the patient needs to be standing for this procedure.
AP view is the alternative to PA view. It may be performed in either an erect or supine position. In this, the x-ray radiation is passed from the front to the back of the chest. This test can be performed on people who are unwell or intubated and cannot stand, but it has some disadvantages such as:
- The X-ray is more likely to show skin folds
- The heart is further away and thus the mediastinal structures (structures including the heart, trachea and oesophagus) may appear magnified
- Scapulae (shoulder bones) may hide some portion of the lungs