Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are persistently low . Cardiac and mediastinal contours are unchanged with the heart size appearing mildly enlarged . Pulmonary vasculature is normal and the hilar contours are within normal limits . Linear opacities in the lung bases are compatible with subsegmental atelectasis . No large pneumothorax or pleural effusion is demonstrated . Previously noted bilateral rib fractures , some of which are acute , are better assessed on the recent CT . Displaced healed and acute sternal fractures are also noted , similar compared to the previous exams . Partially imaged is fusion hardware within the lumbar spine .
    OUTPUT:
    
No interval change from the previous exams . Bibasilar atelectasis with low lung volumes . Re - demonstration of sternal fractures . Known bilateral rib fractures are better assessed on previous CT .