Ground-glass opacity Ground-glass opacity (GGO) represents: - Filling of the alveolar spaces with pus, edema, hemorrhage, inflammation or tumor cells. - Thickening of the interstitium or alveolar walls below the spatial resolution of the HRCT as seen in fibrosis. So ground-glass opacification may either be the result of air space disease (filling of the alveoli) or interstitial lung disease (i.e. fibrosis). The location of the abnormalities in ground glass pattern can be helpfull: - Upper zone predominance: Respiratory bronchiolitis, PCP. - Lower zone predominance: UIP, NSIP, DIP. - Centrilobular distribution: Hypersensitivity pneumonitis, Respiratory bronchiolitis #Diagnosis #Radiology #Pulmonary #CTChest #GGO #GroundGlassOpacity #GroundGlass #Differential #RadiologyAssistant