If you are told that your X-Ray is abnormal, it can mean a few things. The chest contains our airways or wind pipes which are the hollow tube that act as a passage for the air to flow into our lungs during breathing, lungs themselves, blood vessels of the lungs, and the space between the outer lining of the lungs and the chest wall.
Out of these structures, the chest X-Ray is only good at showing the abnormalities that affect the lungs themselves or the space between the outer lining of the lungs and the chest wall. The abnormalities of the wind pipes, and blood vessels (arteries) of the lungs are not usually visible on the chest X-Ray. Even the abnormalities of lungs that are visible need to be larger than 1 centimetre in diameter to become visible on the chest X-Ray. Anything smaller can be missed on the X-Ray.
Air looks black on the chest X-Ray and the body parts or abnormalities look white. The abnormalities of the lungs that are visible on the chest X-Ray are described in a non specific manner as follows:
- Nodule: a white spot less than or equal to 3 centimetre in diameter. It could be caused cancerous, Tuberculosis, pneumonia, fungal infection, or a scar from along infection in the past.
- Mass: a dense white spot that greater than 3 centimetre in diameter. It is usually caused by cancer.
- Consolidation: a white spot that is caused by bacterial or viral infection. Also called pneumonia. It often contains pockets of air within due to which it does not look as densely white as a mass.
- Fibrosis: an area of scarring of the lung causing shrinkage of the affected part of the lung.
- Cavity: a gas filled round space which appears darker than the surrounding lung.
- Collapse: closure of a part of or complete lung due to either blockage of the wind pipe preventing airflow to the affected part of the lung, or pushing effect from the fluid collection within the space between the lining of the lung and the chest wall.
This means that even if the chest X-Ray is abnormal, it is hard to pin point the abnormality with 100% certainty. X-Ray can only suggest or indicate what disease the person may be having but cannot tell the exact diagnosis.
Similarly the abnormalities of the space between the lining of the lungs and the chest wall on the chest X-Ray are described as follows:
- Pleural thickening: a white appearance of the lining of the lung at the periphery of the lungs. This can develop due to healing and scarring of the infection of the lining of the lung in the past.
- Pleural plaques: These look similar to pleural thickening but can be thicker than simple pleural thickening.
- Pleural effusion: This appears as a white lung instead of normal black appearance of the lung due to air in it. It happens as a result accumulation of fluid within the space between the outer lining of the lung and the chest wall pushing the lung away and taking up the space that was occupied by the lung prior to accumulation of the fluid. It can vary in degree with some people filling up a quarter of their left or right side of the chest, and some filling up the entire left or right side of the chest.
- Pneumothorax: pitch black appearance of the air (air looks black of the X-Ray and the body parts or abnormalities look white) accumulated within the space between the outer lining of the lung and the chest wall. This happen when a small blister (some people have them, other do not) on the outer surfaces of the lung gets burst spontaneously (without any injury) or it can happen as a result of an accident with injury to the chest.
This again means that chest X-Ray can only show the abnormality but cannot tell what caused that abnormality. Hence, doctors often recommend a CT scan of the chest whenever any abnormality is found on the chest X-Ray.