<unk>  <unk>  is a finding seen on chest x-ray (radiograph) or computed tomography (CT) imaging of the lungs. It is typically defined as an area of hazy opacification (x-ray) or increased attenuation (CT) due to air displacement by fluid, airway collapse, fibrosis, or a neoplastic process. When a substance other than air fills an area of the lung it increases that area's density. On both x-ray and CT, this appears more grey or hazy as opposed to the normally dark-appearing lungs. Although it can sometimes be seen in normal lungs, common pathologic causes include infections, interstitial lung disease, and pulmonary edema.High-resolution CT image showing<unk> es in the periphery of both lungs in a patient with COVID-19 (red arrows). The adjacent normal lung tissue with lower attenuation appears as darker areas.
Ground-glass opacity
Colloid nodule
Companion shadow
Pleural thickening
Subcutaneous emphysema
Tracheobronchomegaly
Pulmonary consolidation
Peribronchial cuffing