Chest x-ray: Preparation, Procedure, Purpose, Normal Result, Meaning of Abnormal Results and Risks

Updated: October 28, 2019

A chest x-ray is a very common, non-invasive radiology test that produces an image of the chest and other internal organs, such as lungs, heart, large arteries, ribs, and diaphragm. It is also called as Chest radiography, chest roentgenogram, CXR or X-ray - chest.

Preparation for Chest x-ray:

The patient is typically instructed to wear a gown and remove all metal containing objects around the upper body such as necklaces, zippers, bras, buttons, jewelry, eyeglasses, etc. This is because these objects will interfere with the visualization of the tissues. Fasting is not necessary for a routine chest X-ray.
Chest x-rays are generally not done during the first 6 months of pregnancy to avoid unnecessary X-ray radiation exposure to the fetus. Therefore you should inform your health care provider if you are pregnant. protective lead covers may be placed on the abdomen as a precaution to avoid radiation to the fetus when an X-ray is absolutely necessary.

Procedure for Chest x-ray:

During the procedure the chest is briefly exposed to radiation from an X-ray machine and an image is produced on a film or into a digital computer. You will be told to stand in front of a surface adjacent to the film that records the images. The front of the chest is closest to the surface. Another part of the machine that releases the radiation is then placed about 6 feet away, behind the patient.
The positioning will be checked by the technician. When he feel the positioning is appropriate, you will be told to a deep breath and hold your breath when the x-ray is taken while standing in front of the x-ray machine. The image is then captured on the film within a few seconds by activating the device.
The film can be developed within a few minutes to be reviewed by the doctor.
Usually images are taken in different posture. You will first need to stand facing the machine, and then sideways. Both posterior-anterior, or PA view and side-to-side or lateral view are be done.
If a person is too weak, disabled, or hospitalized and is unable to stand, the image can be taken while laying down with the recording surface placed behind the back. It is called an anterior-posterior (AP) view as the image is taken from the front to back in this scenario.
A lateral film is not possible in these situations. This method can also be called a portable chest X-ray as the X-ray machine is wheeled in to the patient in order to take the X-ray. Sometimes other chest images from different positions are taken which may be for special situations. The film plate may feel cold. But other than this you will not feel any kind of discomfort.

Purpose of Chest x-ray:

A chest x-ray is done if you have any of the following symptoms:

• A persistent cough
• Coughing up blood
• Chest pain from a chest injury with a possible rib fracture or lung complication or from heart problems
• Fever
• Difficulty breathing

It may also be done if you have signs of tuberculosis, lung cancer, or other chest or lung diseases. If the chest x-ray is repeated for many times it is called as serial chest x-ray. It may be done to monitor changes found on a past chest x-ray.

Normal Result:

Each organ within the chest cavity absorbs varying degrees of radiation depending on its density, and produces different shadows on the film. The images produced are black and white with only the brightness or darkness defining the various structures. For example, bones of the chest wall that is the ribs and vertebrae, may absorb more of the radiation and thus, appear whiter on the film.
On the other hand, the lung tissue will allow most of the radiation to pass through as it is mostly composed of air. Thus developing the film to a darker appearance. The heart and the aorta will appear whitish, but usually less bright than the bones, which are more denser.

Meaning of Abnormal Results:

Abnormal results is an indication of several disease depending on the particular location the x-ray has been done. These include:

In the lungs:

• Lung tumor which may be noncancerous or cancerous. Irregular and abnormal shadow on the lung fields can detect lung cancer or other lung
• Collapsed lung
• Collection of fluid around the lung
• Abnormally white or hazy shadow on the lung fields that would normally look dark detects pneumonia
• Malformation of the blood vessels
• Tuberculosis
• Scarring of lung tissue
• fluid build-up in the lung or its blood vessels known as pulmonary edema can be seen as diffuse haziness on the lung fields (for example, from congestive heart failure)
• abnormal presence of air between the chest wall and the lung creating a distinct black shadow (darker than the lung fields) between the border of the lung tissue and the inside border of the chest wall (pneumothorax)
• hiatal hernia which is protrusion of the upper portion of the stomach into the chest cavity

In the heart:   

• Problems with the size or shape of the heart, enlarged heart size or cardiomegaly
• Problems with the position and shape of the large arteries
• Evidence of heart failure

In the bones:

• Irregularity in the structure and shape of any of the ribs or the humerus bone of the arm can be seen on a chest X-ray test.
• Fractures such as broken vertebrae or vertebral fractures or other problems of the ribs and spine
• Osteoporosis
• dislocated shoulders

Risks:

There is an exposure of very low radiation. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Therefore there is no harm from this minimal radiation compare to other imaging techniques. It is a simple, quick, inexpensive, and relatively harmless procedure with minimal risk of radiation.
Pregnant women and children are more sensitive to the risks of x-rays. Chest x-rays are generally not done during the first 6 months of pregnancy to avoid any kind of complication from radiation. There is a possibility that the radiation could affect the fetus.