Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low with persistent moderate relative elevation of the left hemidiaphragm compared to the right side . Patchy opacities in the lower lungs can probably be attributed to atelectasis in that setting . Limitations of technique makes it difficult to exclude subtle pneumonia , however . There is no pleural effusion or pneumothorax . Bony structures are unremarkable .
    OUTPUT:
    
Left lower lobe opacity , which can probably be attributed to atelectasis in the setting of low lung volumes , although it is difficult to completely exclude pneumonia .