Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette size is mildly enlarged . The aorta is slightly unfolded . The mediastinal and hilar contours are otherwise unremarkable . Linear opacities in the left lung base likely reflect subsegmental atelectasis . Remainder of the lungs are clear without focal consolidation . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Left basilar subsegmental atelectasis .