Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is mild relative elevation of the left hemidiaphragm with streaky basilar opacification suggesting atelectasis , overall with volume loss , but an infectious process could be considered , particularly regarding a patchy left lower lobe opacity on the lateral view . There is no pleural effusion or pneumothorax . The cardiac , mediastinal and hilar contours appear within normal limits .
    OUTPUT:
    
Patchy left lower lobe opacity . This may be consistent with pneumonia , but atelectasis could also be considered as the etiology , in the appropriate clinical setting .