Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright AP radiograph was obtained . This demonstrates small lung volumes and resulting bronchovascular crowding . The heart is enlarged though evaluation of heart size with AP technique is suboptimal . Patient is additionally rotated . There is observation of the left hemidiaphragm as well as retrocardiac opacities for which infection can not be excluded . Obscuration of the costophrenic angles bilaterally may reflect bilateral pleural effusions .
    OUTPUT:
    
Retrocardiac left lower lobe opacity concerning for infection or alternatively atelectasis . Bronchovascular crowding secondary to low lung volumes . Enlarged heart .