Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The aorta demonstrates atherosclerotic calcifications at the knob . The mediastinal and hilar contours are otherwise unremarkable . The pulmonary vasculature is normal . Minimal linear opacities within the lung bases , more pronounced on the left , likely reflect areas of subsegmental atelectasis . A small left pleural effusion is likely present . There is no focal consolidation or pneumothorax . There are mild degenerative changes noted in the thoracic spine . No definite displaced rib fracture noted .
    OUTPUT:
    
Bibasilar subsegmental atelectasis with small left pleural effusion . No definite displaced rib fractures are identified . If there is continued concern for a rib fracture , recommend a dedicated rib series .