Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mild to moderately enlarged . The main pulmonary artery contour , as well as central pulmonary arteries appear again enlarged . The aortic arch is calcified . There is a small pleural effusion on the left with associated opacity probably due to atelectasis . The opacity in the medial right lower lung is probably due to a atelectasis in the costophrenic sulcus . There is probably a very mild degree of vascular congestion but less striking than on the prior study .
    OUTPUT:
    
Cardiomegaly and marked enlargement of central pulmonary arteries ; pulmonary vascular congestion appears very mild , however . Opacities at the lung bases probably due to atelectasis with a small left - sided pleural effusion .