Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Opacity in the right lower lobe persists but is slightly less conspicuous compared to the prior exam , most likely atelectasis . Otherwise , the lungs are clear without edema . No pleural effusion or pneumothorax . Lung volumes remain low . The heart size is normal . The mediastinum is not widened . No acute osseous abnormality .
    OUTPUT:
    
1 . Persistent low lung volumes with slight interval decrease in the left lower lobe opacity that is most likely atelectasis . 2 . No evidence of fracture but this exam is not dedicated for imaging of the ribs . There is clinical concern for fracture , dedicated radiograph should be obtained .