The term "glass lung," or ground-glass opacity, refers to a nonspecific finding where an area of the lung appears hazy on a CT scan. This may indicate an infection, an acute alveolar disease or other causes.
The hazy image of the lung can be caused by any of various reasons, such as air spaces, partial collapse of alveoli, inflammation and interstitial thickening.
A specific area on the lung that is shown to be affected is called a ground-glass density nodule. To find all the ground-glass nodules in a person's lungs, numerous CT scans are necessary. It has been shown that low-dose CT scans reduce the mortality rate in people with lung cancer.