Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal , and hilar contours appear unchanged . There is similar moderate relative elevation of the right hemidiaphragm compared to the left . A prominent pericardial fat pad is again noted along the left apex , obscuring the costophrenic sulcus , and accordingly making it difficult to exclude a small pleural effusion . There is no evidence for pleural effusion on the right . There is no pneumothorax . Although right basilar opacity has mostly resolved , leaving only a streaky residual linear opacity suggesting minor scarring or atelectasis , there is a patchy new retrocardiac opacity in the left lower lobe , raising concern for pneumonia . Atelectasis would be a differential consideration , however .
    OUTPUT:
    
Patchy opacity in the left lower lobe , non-specific possibly due to pneumonia in the appropriate clinical setting .