What is the difference between an acinar opacity and an air alveologram?
An acinar opacity refers to an ill-defined nodular opacity in the lung measuring 0.5 to 1 cm due to opacification of an acinus with surrounding aerated lung. Acinar opacities may coalesce and lead to larger areas of consolidation.
An air alveologram is the converse and refers to a small rounded lucency in the lung when a normally aerated acinus is surrounded by opacified lung parenchyma. Both are signs of airspace lung disease.