Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear unchanged including borderline cardiomegaly . A vague opacity persists in the right upper lobe , described as an irregular nodule on the prior CT and not well characterized on this examination . There is also patchy opacity in the left lower lung , similar to increased compared to prior studies , although it may be due to exaggeration or increase in pre-existing minor atelectasis . There is no definite pleural effusion or pneumothorax .
    OUTPUT:
    
Increased opacity at the left lung base , which may be due to increase in existing atelectasis at the site rather than pneumonia . However , particularly if clinical concern for pneumonia persists , standard PA and lateral radiographs may be helpful to evaluate further and directly compare to earlier studies when clinically feasible .