(Chest Radiography, CXR)

Procedure Overview

What is a chest X-ray?

A chest X-ray is a type of diagnostic radiology procedure used to examine the chest and the organs and structures located in the chest. Chest X-rays may be used to assess the lungs, as well as the heart (either directly or indirectly) by looking at the heart itself. Certain conditions of the heart may cause changes in the lungs and/or the vessels of the lungs. Changes in the normal structure of the heart, lungs, and/or lung vessels may indicate disease or other conditions.

Chest X-rays may provide important information regarding the size, shape, contour, and anatomic location of the heart, lungs, bronchi, great vessels (aorta, aortic arch, pulmonary arteries), mediastinum (an area in the middle of the chest separating the lungs), and the bones (cervical and dorsal spine, clavicles, shoulder girdle, and ribs).

What are X-rays?

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs and other internal structures for diagnostic purposes. X-rays pass through body tissues onto specially treated plates (similar to camera film) and a “negative” type picture is made (the more solid a structure is, the whiter it appears on the film).

Depending on the results of the chest X-ray, additional tests or procedures may be requested by your physician for further diagnostic information.

Other related procedures that may be used to diagnose problems of the chest and respiratory tract include chest fluoroscopy, chest ultrasound, computed tomography (CT scan) of the chest, lung biopsy, lung scans, mediastinoscopy, positron emission tomography (PET scan) of the chest, pleural biopsy, thoracentesis, sinus x-rays, pulmonary angiogram, bronchoscopy, and bronchography. Please see these procedures for additional information.

Anatomy of the respiratory system

The respiratory system is made up of the organs involved in the interchanges of gases, and consists of the:

  • Nose

  • Pharynx

  • Larynx

  • Trachea

  • Bronchi

  • Lungs

The upper respiratory tract includes the:

  • Nose

  • Nasal cavity

  • Ethmoidal air cells

  • Frontal sinuses

  • Maxillary sinus

  • Larynx

  • Trachea

The lower respiratory tract includes the lungs, bronchi, and alveoli.

What are the functions of the lungs?

The lungs take in oxygen, which cells need to live and carry out their normal functions. The lungs also get rid of carbon dioxide, a waste product of the body's cells.

The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue. They take up most of the space in the chest, or the thorax (the part of the body between the base of the neck and diaphragm).

The lungs are enveloped in a membrane called the pleura.

The lungs are separated from each other by the mediastinum, an area that contains the following:

  • The heart and its large vessels

  • Trachea (windpipe)

  • Esophagus

  • Thymus

  • Lymph nodes

The right lung has three sections, called lobes. The left lung has two lobes. When you breathe, the air enters the body through the nose or the mouth. It then travels down the throat through the larynx (voice box) and trachea (windpipe) and goes into the lungs through tubes called main-stem bronchi.

One main-stem bronchus leads to the right lung and one to the left lung. In the lungs, the main-stem bronchi divide into smaller bronchi and then into even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli.

Reasons for the Procedure

Chest X-rays may be used to assess heart status (either directly or indirectly) by looking at the heart itself, as well as the lungs. Changes in the normal structure of the heart, lungs, and/or lung vessels may indicate disease or other conditions.

Conditions that may be assessed with a chest X-ray include, but are not limited to, the following:

  • Heart enlargement (which can occur with congenital heart defects or cardiomyopathy)

  • Pericardial effusion - a buildup of excess fluid in between the heart and the membrane that surrounds it, often due to inflammation

  • Pleural effusion - a collection of blood or fluid around the lung

  • Pneumonia, persistent cough, and other lung conditions

  • Aneurysms - ballooning of the walls of the great blood vessels, such as the aorta

  • Bone fractures

  • Calcification of heart structures (such as heart valves or aorta)

  • Tumors or cancer

  • Herniation of the diaphragm (the breathing muscle, the diaphragm, moves out of place)

  • Pleuritis - inflammation of the lining of the lung

  • Pulmonary edema (“fluid in the lungs,” which can occur with congenital heart disease or congestive heart failure)