One thing that can show on a CT scan or X-ray is a degree of haziness referred to as opacity. This can indicate a concern, but your doctor may want more testing to determine the cause of any potential lung issues.

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Even though over 80 million people undergo computed tomography (CT) scans each year in the United States, some of the words and phrases related to this imaging test can be complicated and hard to understand.

For example, one term that healthcare professionals might use in reference to a lung CT scan is “opacity.” This is a radiological term that refers to the hazy gray areas on images made by CT scans or X-rays.

This article will provide information about lung opacity, whether it means you have lung cancer, and what the outlook may be for those with lung opacity.

Ground-glass opacity is a radiological term that refers to hazy gray areas on the images made by CT scans or X-rays. It indicates increased density in these areas.

Typically, the lungs appear black on a CT scan or X-ray. This shows that they are free of blockages. When gray areas are visible instead, it means that something is partially filling this area inside the lungs.

These gray areas are referred to as ground-glass opacity. Ground-glass opacity can be a sign of:

  • fluid, pus, or cells filling the air space
  • walls of the alveoli thickening
  • space between the lungs thickening

Ground-glass opacity can result from a variety of causes, according to 2020 research.

Sometimes it is temporary and the result of a short-term illness. In other cases, it can signify a chronic or more serious condition. Ground-glass opacity can also indicate an infection or other inflammatory process, which is usually what a clinician will share with you or your loved one who has had a CT scan or X-ray.

Healthcare professionals see lung opacities on imaging scans. Your doctor may suggest a scan of your lungs if you are experiencing:

  • shortness of breath
  • persistent coughing
  • coughing with yellow, green, or bloody mucus
  • chest pains
  • blue- or white-tinged fingertips or lips
  • voice changes

Opacities are also likely to show up on a scan if you have a history of smoking or vaping.

It’s also good to know that chest CTs are used to screen for risk of lung cancer, and a physician may order a CT scan if you have a history of smoking.

Opacities in the lungs can be caused by a variety of both acute and chronic concerns. Some potential reasons for lung opacity include:

Depending on the type of opacity found, your doctor may also do cardiac testing to determine if heart conditions are playing a role.

Lung opacities can indicate many conditions besides cancer. Many times they are benign (noncancerous). They may be due to infections, hemorrhages, a history of smoking, and even COVID-19.

Lung opacities are common, 2021 research suggests. They can indicate a broad range of conditions, and your doctor may need to do further scans and tests to determine the exact cause of any lung opacities.

Lung opacity can show up on the imaging scan in a variety of ways, depending on the underlying condition. Some conditions will result in multiple types of opacities.

Opacities may be:

  • Diffuse: This describes when opacities show up in multiple lobes or both lungs. This is usually the result of fluid, damaged tissue, or inflammation.
  • Nodular: This can mean either a malignant or benign condition. Because this opacity can be caused by small scars from a recent infection, doctors may choose to watch it over several scans to see if it grows.
  • Centrilobular: This type of opacity can appear within one or several lobules of the lung. The connective tissues between the lobules will be unaffected in this type of opacity.
  • Mosaic: Opaque areas vary in intensity in this pattern. It is due to small arteries or airways within the lung being blocked.
  • Crazy paving: This describes a linear pattern that develops when spaces between the lobules widen.
  • Halo sign: This describes when opacity fills the area around the nodules.
  • Reversed halo sign: The opacity will be surrounded by liquid-filled tissue.

Lung opacity can indicate different conditions that have their own treatment plans. Depending on the cause, your doctor may suggest:

If the lung opacity is due to cancer, treatment will vary depending on the severity and type. Treatment may include radiation, chemotherapy, and surgery.

Lung opacity can result from many different causes, with varying degrees of seriousness.

Some conditions that cause lung opacity, like viral infections, are typically short-lived with low long-term risk. Other conditions, like alveolar hemorrhage and lung cancer, require more serious treatments.

Ground-glass opacity nodules can be divided into two types: pure and partially solid. Pure nodules do not contain any solid mass, whereas partially solid nodules do have solid components.

A 2019 study found that in cases when lung opacity showed cancer, pure ground-glass opacity nodules were more likely to be seen in earlier stages of lung cancer. There was also less lymph node invasion compared with ground-glass opacity nodules that also include solid masses.

Additionally, pure ground-glass opacity nodules took longer to double in size than ground-glass opacity nodules with solid masses in these studies. This means that lung cancer outlook may be better when a person has pure ground-glass opacity, compared with scans that showed a solid part in the nodules.

After a CT scan or X-ray, a radiologist will look at the scan to determine if there are areas of concern. One thing that can show on a CT scan or X-ray is a degree of haziness referred to as opacity.

Opacity on a lung scan can indicate a concern, but the cause can vary. Your doctor may recommend additional testing to determine the exact cause of any potential lung issues.

The outlook and treatment options available will depend on the cause of the opacity.