Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is moderate cardiomegaly and mildly widened mediastinum which is likely exaggerated by low lung volumes and appears stable when compared to prior studies . There is opacification in the retrocardiac space that appears stable when compared to prior studies but in the appropriate clinical setting could represent pneumonia . There is a linear opacification left upper lobe which represents atelectasis . There is mild pulmonary vascular congestion without evidence of pulmonary edema . There are no pleural effusions .
    OUTPUT:
    
1 . Unchanged opacification in the retrocardiac space that in the appropriate clinical setting could represent pneumonia . 2 . Linear atelectasis in the left upper lobe . 3 . Mild pulmonary vascular congestion without pulmonary edema .