Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Lung volumes are markedly low limiting assessment . An AICD is again seen with leads extending to the expected region of the right arm and right ventricle . Cardiomegaly appears grossly unchanged . A rounded calcified density projecting over the left chest wall likely represents a calcified breast implant . Subtle opacity at the right lung base appear slightly more conspicuous than on prior , may represent atelectasis , though pneumonia can not be excluded in the correct clinical context . Bronchovascular crowding likely accounts for perihilar opacities as these appear unchanged from prior . No large effusion or pneumothorax is seen . Mediastinal contour is stable with calcified thoracic aorta . Imaged osseous structures appear intact .
    OUTPUT:
    
Subtle opacity at the right lung base , more conspicuous than on prior , question atelectasis versus pneumonia .