During testing for chronic obstructive pulmonary disease (COPD), “spirometry” tests are always used to measure a person’s ability to breathe. Spirometry measurements are the main way that healthcare providers can know for sure that a person has COPD. Spirometry is used to show whether a person’s airways are blocked by the lung damage caused by COPD.
Other tests are commonly used to double-check the diagnosis of COPD. These tests can also show how much lung damage the person has, and find out the stage of the disease. These tests include:
- Blood tests, such as pulse oximetry and arterial blood gas testing
- Other breathing tests, such as lung volume measurement and lung diffusion capacity
- Exercise testing
Another kind of testing is called “imaging.” It is not used all the time when testing people for COPD, but it is used for many patients.
What is imaging?1
Imaging is a kind of medical testing that uses technology to capture an image or other kind of representation of the inside of a person’s body. Imaging tests that are sometimes used to help diagnose COPD are:
- Chest x-ray
- CT scan
- ECG
Imaging is mainly used to find out if a person’s symptoms are being caused COPD, or by some other condition that has similar symptoms. Imaging tests are not used alone to diagnose a person with COPD. But they can be a valuable additional tool to aid in a correct diagnosis.
What are chest x-rays, and how are they useful?1,2,3
A chest x-ray takes a picture of the inside of a person’s chest by passing a special kind of radiation energy through the body very quickly and painlessly. This image shows the lungs, heart, blood vessels, ribs, and spine.
Chest x-rays are often used to make sure that a person’s symptoms are caused by COPD, and not other conditions such as:
- Pneumonia
- Lung cancer
- Congestive heart failure
- Collapsed lung
Sometimes, the chest x-ray may show some signs of the lung damage caused by emphysema. But for patients in an early stage of the disease, the x-ray might not show any symptoms of COPD at all.
What is a CT scan, and how is it useful?1,2
A kind of imaging called “computed tomography” is called a “CT scan” for short. CT scans are used to create very detailed images of the inside of the body. An x-ray takes only a couple of large pictures, but the CT scan takes a large number of smaller pictures.
The CT scan can usually provide more information than an x-ray can. For instance, a CT scan can show damage to the lungs that is caused by emphysema before an x-ray can detect it.
However, CT scans are used less often than chest x-rays for helping diagnose people with COPD. They are very expensive, and the information provided by the chest x-ray is often enough. They tend to be used when it is very hard to tell if a person has COPD or not. They are also used more often if a person needs lung surgery to treat COPD.
What is an ECG, and how is it useful?1,4
“Electrocardiography” is called “ECG” for short. ECG is a way of recording the heart’s electrical activity. During an ECG test, small patches called electrodes are placed on the skin of a person’s chest. The ECG machine draws lines on a paper that show how the heart is functioning.
ECGs are not used as often as chest x-rays for people with COPD. However, they can be used to detect certain signs of how COPD lung damage is affecting the heart. ECGs can also be used to find out if a person with COPD has other kinds of heart problems.