Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . There may be mild , central pulmonary vascular congestion . The cardiac silhouette is stably enlarged . Again noted are aortic arch calcifications . There appears to be an opacity in the retrocardiac region . Evaluation of the lateral film is limited due to patient positioning and poor inspiratory effort . Possible small right pleural effusion is present . There is no pneumothorax .
    OUTPUT:
    
Retrocardiac opacity which could be consistent with pneumonia in the appropriate clinical context .