Chest X-Ray

  • Medical Author:
    Siamak N. Nabili, MD, MPH

    Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View the Men's Health Screenings Slideshow

Chest X-ray definition and facts

  • A chest X-ray is most commonly used to detect abnormalities in the lungs, but can also detect abnormalities in the heart, aorta, and the bones of the thoracic area.
  • Extra metallic objects, such as jewelry are removed from the chest and neck areas for a chest X-ray to avoid interference with X-ray penetration and improve accuracy of the interpretation.
  • A chest X-ray can be used to diagnose many conditions and diseases such as pleurisy, pulmonary edema, pneumonia, bronchitis, cysts, tumors, cancers, asthma, pericarditis, cardiomegaly, heart failure,  pneumothorax, and fractures.

What is a chest X-ray?

A chest X-ray is a radiology test that involves exposing the chest briefly to radiation to produce an image of the chest and the internal organs of the chest. An X-ray film is positioned against the body opposite the camera, which sends out a very small dose of a radiation beam. As the radiation penetrates the body, it is absorbed in varying amounts by different body tissues depending on the tissue's composition of air, water, blood, bone, or muscle. Bones, for example, absorb much of the X-ray radiation while lung tissue (which is filled with mostly air) absorbs very little, allowing most of the X-ray beam to pass through the lung.

What is a shadow on a chest X-ray?

Due to the differences in their composition (and, therefore, varying degrees of penetration of the X-ray beam), the lungs, heart, aorta, and bones of the chest each can be distinctly visualized on the chest X-ray. The X-ray film records these differences to produce an image of body tissue structures and these are shadows seen on the X-ray. The white shadows on chest X-ray represent more dense or solid tissues, such as bone or heart, and the darker shadows on the chest X-ray represent air filled tissues, such as lungs.

How is the chest X-ray procedure performed?

Patients obtaining a chest X-ray will often be requested to use an X-ray gown, and extra metallic objects such as jewelry are removed from the chest and/or neck areas. These objects can block X-ray penetration, making the result less accurate. Patients may be asked to take a deep breath and hold it during the chest X-ray in order to inflate the lungs to their maximum, which increases the visibility of different tissues within the chest.

The chest X-ray procedure often involves a view from the back to the front of the body as well as a view from the side. The view from the side is called a lateral chest X-ray. Occasionally, different angles are added in order for the radiologist to interpret certain specific areas of the chest.

The radiology technologist or technician is a trained, certified assistant to the radiologist who will help the patient during the X-ray and actually perform the X-ray test procedure. After the chest X-ray is taken and recorded on the X-ray film, the film is placed into a developing machine, and this picture (which is essentially a photographic negative) is examined and interpreted by the radiologist.

How do doctors interpret chest X-rays?

A radiologist is a physician specialist trained to interpret images of the body produced on films. After the films are produced by the technician they are developed and reviewed by the radiologist for interpretation. After the radiologist reviews the chest X-ray, occasionally further images or angles may be necessary. Once all the films have been reviewed by the radiologist, a report is generated which is transmitted to the ordering practitioner.

In the past, the doctors interpreting the films placed the films in front of a source of light for better visualization of the shadows on the chest X-ray. This usually consisted of a fluorescent light source placed in metal box and covered by a white plastic.

More recently, newer technology has replaced this old reading technique in many health care facilities and radiology offices. This advanced technology has eliminated the need for the actual physical films to be used and placed on a light box for interpretation. The images, once taken and developed, are uploaded into a computer with special software that enables digital images to be viewed on a computer screen. The doctor can look at the images on the screen, interpret the results, and comment on the computer all within minutes after the images were taken.

Additionally, this technology allows for ability to easily look at any previous images taken from the same patient. It also essentially eliminates the possibility of lost X-rays and speeds up the interpretation of X-rays, and the communication between doctors about the results.

Where are chest X-ray's performed?

Chest X-rays are one the most commonly ordered radiology tests. Once they are ordered by a physician, they can be performed in hospitals, emergency rooms, outpatient radiology facilities, and some doctors offices.

What are the risks of a chest X-ray?

Chest X-rays expose the patient briefly to a minimum amount of radiation. Any radiation exposure has some risk to the tissues of the body. The radiation exposure in a chest X-ray is minimized by the type of X-ray high-speed film, which does not require as much radiation exposure as in the past. The radiology technician is guided by technique standards which have been established by national and international guidelines. These guidelines are designed and reviewed by both the Department of Health and Human Services and national and international radiology protection councils.

Women who are pregnant, especially in early pregnancy, should notify their physicians, as the fetus is at risk for harm with any radiology technique. X-rays are typically avoided in pregnant patients unless absolutely necessary, in which case the patient's abdomen is covered with a special lead gown to block the radiation from the fetus.

What are reasons for ordering chest X-rays?

There are many reasons why doctors order chest X-rays. Frequently, they are ordered for symptoms of shortness of breath, cough, or chest pain. However, there are many other signs and symptoms that may prompt a doctor to order chest X-rays. They may also be done as a routine check examination.

Sometimes chest X-rays are required before operations to see if there is any evidence of heart or lung disease that may need to be addressed before the procedure. This is called a pre-operative chest X-ray (or pre-op chest X-ray requirement).

Who can interpret chest X-rays?

Many doctors are trained to interpret chest X-rays. In addition to radiologists, who have special training in reading all radiology films, primary care physicians, internists, pediatricians, emergency room doctors, anesthesiologists, heart doctors (cardiologist), lung doctors (pulmonologist) and lung surgeons are the doctors who frequently interpret chest X-rays as a part of their routine practice.

What can be seen on a normal chest X-ray?

Normal chest X-ray shows normal size and shape of the chest wall and the main structures in the chest.

As described earlier, white shadows on the chest X-ray signify solid structures and fluids such as, bone of the rib cage, vertebrae, heart, aorta, and bones of the shoulders. The dark background on the chest X-rays represents air filled lungs. These lung fields are seen on either side of the heart and the vertebrae located in the center of the film.

What are some common chest X-ray abnormalities?

Chest X-ray is generally used in combination with other clinical data such as, physical examination and the patient's history and symptoms. It can also be used in combination of other radiology test to support, confirm, or exclude many conditions or diagnoses.

A chest X-ray can be used to define abnormalities of the lungs such as excessive fluid (fluid overload or pulmonary edema), fluid around the lung (pleural effusion), pneumonia, bronchitis, asthma, cysts, and cancers. Heart abnormalities, including fluid around the heart (pericardial effusion), an enlarged heart (cardiomegaly), heart failure, or abnormal anatomy of the heart can be revealed on the films. Certain bony structures of the chest and broken bones (rib fracture) or abnormalities of the bones of the spine (vertebral fracture) in the chest can often be detected.

REFERENCE: National Institutes of Health. "What is a chest X-ray?"

Last Editorial Review: 8/22/2016

Reviewed on 8/22/2016
References
REFERENCE: National Institutes of Health. "What is a chest X-ray?"

Health Solutions From Our Sponsors