Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . Linear left base opacity seen on the frontal view , not substantially on the lateral view , most likely presents atelectasis . No definite focal consolidation to suggest pneumonia is seen . There is no pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Linear left base opacity more likely represents atelectasis than pneumonia , seen only on the frontal view , not substantiated on the lateral view .