A heart X-ray is a nonspecific term that may refer to a chest X-ray or a specialized test called coronary computed tomography angiography (CCTA), which uses X-ray technology and dye to make a detailed image of the heart.

A chest X-ray shows an image of the chest, including the heart, lungs, and bone structures. Although these X-rays can provide valuable information about the heart, they do not show images of the inside of the heart.

For a CCTA, a doctor injects a special dye that circulates the body and highlights the cardiac blood vessels clearly on a nearby monitor. This allows the doctor to check for blockages and provide pictures of the heart.

This article discusses heart X-rays in more detail, including what doctors may use them for, the risks, how to prepare, and more.

Doctors may initially order a chest X-ray to check for suspected issues with the heart. The chest X-ray can show the position of the heart, as well as its size and shape.

A doctor may order a chest X-ray if a person has:

In some cases, a doctor may order a CCTA scan to check the heart in more detail. The CCTA scan can check for blockages and reveal whether the arteries have narrowed.

Other reasons a doctor may order a CCTA include:

  • checking the status of coronary graphs
  • following an inconclusive stress test
  • checking for abnormalities in coronary arteries
  • assessing the possible causes of low to intermediate pain in the emergency room
  • determining the cause of non-acute chest pain

X-rays are a form of ionizing electromagnetic radiation. Many medical machines use X-rays to examine the inside structures of the body. Types of X-ray procedures include fluoroscopies, radiographies, and CT scans.

During a procedure, X-rays travel from the machine through the body. Different tissues within the body have different radiological densities, so they absorb different amounts of the X-rays.

The radiological density of a material depends on its density and its atomic number. There are four possible densities on an X-ray film image, or radiograph: gas, fat, water, and mineral. The radiograph appears black wherever there is gas, as gas does not absorb X-rays. Denser structures absorb more X-rays, so the image changes from black to gray to white with increasing density.

For instance, the calcium inside bone has a high atomic number, so bones absorb a lot of X-rays. This causes them to show up as a strong white color on X-ray images.

Although an X-ray itself cannot show heart tissue in detail, a CCTA uses X-rays, alongside a special dye doctors inject into the bloodstream, to provide images of the blood vessels and heart. The dye has a higher radiological density, so it shows up on X-ray scans.

Whereas a chest X-ray is a single, stationary image of the chest from either the front or side of the body, a CCTA obtains multiple images of the heart as the scanner crosses the chest cavity from front to back.

Chest X-rays use a very small amount of radiation — about one-fifth of the total radiation a person gets from natural sources each year. CCTA produces images using radiation and dyes, both of which pose a small risk to some people.

The amount of radiation in X-rays can vary. With any radiation exposure, a person has at least some risk of developing cancer. However, the benefits of testing and diagnosis often outweigh the potential risk.

CCTA uses a small amount of dye that a healthcare professional injects into the blood. Although these dyes are generally safe, a person with kidney issues should avoid tests that use them. Some individuals may also have an allergic reaction to the dye.

For either type of X-ray, a person who is pregnant or nursing should tell the doctor beforehand. They will need to take additional precautions, postpone the test, or order a different test.

Learn more about radiation sickness.

A person typically does not need to do much to prepare for an X-ray. They should go to the facility conducting the test wearing easy-to-remove clothing and jewelry, as they may need to remove certain pieces of clothing for the X-ray.

A person who is pregnant should make sure to mention this to the technician. The technician may recommend postponing the test, or they may take additional steps to protect the fetus.

Chest X-rays and CCTAs use specialized equipment.

During a chest X-ray, a technician will likely have the person stand, sit, or lie near the machine. They will then focus the X-ray on the chest and take several images.

They will likely cover other areas with a lead vest to help prevent unnecessary exposure to radiation.

During a CCTA, the technician will need to inject a dye into the person’s blood. They will use an IV line to administer the dye. This may cause slight discomfort, as a healthcare professional will have to insert a needle into the person’s forearm.

The test can take some time, which can cause discomfort for some people. A nurse or doctor may administer medication to help the person relax and remain still during the test. A person is typically alone in a room during the exam process.

Once the imaging is complete, the technician will remove the IV line. Typically, a person will be able to leave shortly afterward.

Both types of X-rays produce images of the heart, which technicians typically store in a computer. A radiologist — a doctor who specializes in reading X-rays and other imaging tests — will review the results prior to sending them to the doctor. The doctor may print them out or project them to share with the person.

Often, a doctor can review the results of a chest X-ray with the person within a few minutes of the procedure.

Similarly, a doctor can often explain the preliminary results of a CCTA within a few minutes of the test.

In some cases, a doctor may order one or more follow-up tests if the results are inconclusive or if they need more information.

A person’s outlook will largely depend on what the X-ray reveals. A person should talk with their doctor about abnormal results to find out what they mean. The doctor can also explain the treatment options and the person’s overall outlook.

Doctors may order additional testing or make recommendations for treatment following an X-ray.

In addition to formal treatment, a doctor may advise a person to make certain lifestyle adjustments to help lower their risk of developing heart disease.

Depending on the person’s current lifestyle and habits, the doctor may recommend:

  • quitting smoking
  • limiting alcoholic beverages
  • reaching and maintaining a moderate weight
  • exercising regularly
  • taking steps to manage stress
  • eating a nutritious, well-balanced diet
  • controlling blood pressure and cholesterol levels
Learn more

Learn more about managing and reducing the risk of heart disease.

Heart X-rays can show a detailed image of the heart. A doctor may order a chest X-ray or CCTA as a preliminary diagnostic tool for checking out the heart and arteries.

The exams are similar, but a CCTA scan often involves the use of a contrast dye.

A radiologist will review the results of the test and send a report to the doctor who ordered the test.

The doctor will then review the results with the person and make recommendations for additional testing or treatment, as appropriate.