A chest x-ray is usually the first examination performed if there is a suspicion that some pathological process is present inside the chest cavity. This type of examination exposes the human body to some level of radiation, but it is still a very simple, fast, and very informative imaging technique. Here is some basic information on how it is performed, as well as basic instructions on how to read the radiologist’s report.
How Is A Chest X-Ray Performed?
A chest x-ray is usually performed in 2 positions – posterior-anterior (PA) and lateral.
Using the PA technique, the front side of the chest is positioned close to the film, while the emitted x-rays hit the back side of the chest and pass through the chest cavity back-to-front. The image obtained this way is two-dimensional, which means that there is no way to determine the position of a pathological structure in the horizontal plane. For example, if we notice some pathological structure on the PA x-ray, we don’t know whether it is located in front or behind the trachea.
That is where the lateral position comes in. Combined interpretation of PA and lateral chest x-ray images can give a somewhat three-dimensional view of the chest cavity. For the lateral chest x-ray, the lateral side of the body (left or right) is positioned close to the film, while the x-rays hit the opposite side.
How Is A Chest X-Ray Interpreted?
In order to interpret a chest x-ray image, you need to have proper education. Radiologists are medical professionals specialized in the interpretation of all kinds of radiographic images. Reading the interpretation of the x-ray image made by a radiologist is often challenging, as many technical terms are used. However, with some basic knowledge, you can actually recognize whether the findings are pathological or normal.
Here is the usual structure of the radiographic interpretation, although some parts may be left out if the radiologist considers them irrelevant. Firstly, the radiologist will comment the quality of the image by stating that the image is technically appropriate or inappropriate. This depends on the proper positioning while obtaining the chest x-ray and it can affect the interpretation. Next, the radiologist examines the soft tissues and bony structures of the chest walls and looks for fractures, the presence of air in the soft tissue, etc. After that, the lungs, large blood vessels, the heart, and other structures in the chest cavity are examined and commented.
Common Pathological Findings On A Chest X-Ray
Pathological findings in the chest cavity are represented either as shadows (appearing white) or lucent areas (appearing dark). Pneumonia, the presence of liquid in the pleural cavity, and lung tumors are lucent, because they prevent the x-rays from hitting the film. On the other hand, diseases which reduce the density of the lungs, such as emphysema, are presented as shadows.
Sometimes, the radiologist will suggest the most probable diagnosis, but in many cases, it still needs to be confirmed by some more invasive methods. In most cases, chest radiography is used in order to exclude the presence of some disease, rather than to confirm the specific diagnosis.
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