Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single AP chest radiograph was obtained . The lungs are well expanded . Linear opacities in the right lung base are predominantly horizontal . There is no focal consolidation , effusion , or pneumothorax . There are no abnormal cardiac or mediastinal contours .
    OUTPUT:
    
Increased markings at the right lung base may represent atelectasis . Infection ca n't be excluded in the appropriate clinical context .