Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest demonstrates an enlarged heart , and stable in size when compared to prior examination dated ___ . There is a retrocardiac opacity and obscuration of the left hemidiaphragm concerning for atelectasis although an infectious process can not be excluded . Blunting of bilateral costophrenic angles are concerning for small bilateral pleural effusions . The hilar contour is unchanged in appearance when compared to prior radiographs . No osseous abnormality is identified .
    OUTPUT:
    
Retrocardiac opacification concerning for left lower lobe atelectasis versus pneumonia . Cardiomegaly with stable appearance of the mediastinal silhouettes when compared to prior radiographs dated ___ .