How Chest X-Rays Can Help Diagnose COPD

If your doctor suspects you have chronic obstructive pulmonary disease (COPD), you will be likely be asked to have a chest X-ray. A chest X-ray is a simple, non-invasive imaging technique that uses electromagnetic waves to create a one-dimensional picture of your heart, lungs, and diaphragm.

While a chest X-ray cannot make a diagnosis of COPD, especially in early-stage disease, it can help support it. By and large, an abnormal chest X-ray is generally only seen when the damage to the lungs is extensive.

What a Chest X-Ray Can Tell Us

In early-stage disease, a chest X-ray may, in fact, appear quite normal. This doesn't mean that there is no damage; it is simply that the test has limitations as to how much it can visually tell us. It can neither describe your individual lung capacity nor the force by which you can inhale or exhale air.

What it can do is give us a visual reference point by which to compare any changes that may develop over time. As such, doctors will typically recommend a chest X-ray every one or two years depending on how far along your COPD is.

In later-stage disease, visual changes will become more apparent. One of the most obvious features will be the so-called hyperinflation of the lungs. When this happens, the doctor will be able to see several things on the X-ray:

• A flattening of the diaphragm as the lungs press down on the muscle
• Increased chest size as measured from front to back
• An elongated and narrow heart
• Pockets of air called bullae around a half inch in size or larger

In the event your doctor needs a more extensive view of the lung structure and damage, a computed tomography (CT) scan may be ordered. Where a chest X-ray will only deliver a one-dimensional image of the lungs, a CT scan will take a series of images to create a more three-dimensional representation. In doing so, the CT scan can pick up finer detail and provide doctors a more complete portrait of the person's COPD.

How COPD Is Diagnosed

To make an accurate diagnosis of COPD, a comprehensive evaluation would be performed to provide a baseline assessment of your current health, your family history, your smoking status, and any environmental or occupational toxins you may have been exposed to.

In addition to a chest X-ray, you may be asked to undergo one or several of the following tests:

• Arterial blood gasses to determine how much oxygen and CO2 is in your blood
• Pulmonary function tests to measure how well your lungs inhale and exhale and how efficiently they transfer oxygen to the blood
• Bronchoscopy using a flexible, lighted scope to visually examine the lung
• Pulse oximetry to measure the oxygen saturation in your blood
• Six-minute walk test to assess your respiratory response to exercise
• AAT deficiency screening to determine whether there is a lack of the alpha-1 anti-trypsin (AAT) protein which helps protect the lungs and liver

If a positive diagnosis is returned, your doctor would next determine the stage of your disease and design a treatment plan to help slow the progression of COPD.