Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear left lower lobe opacities identified . The right lung is clear . No pleural effusion or pneumothorax is identified . The heart size is top normal . The mediastinal contours are normal . There is no free air beneath the diaphragm . No acute osseous or soft tissue abnormality identified .
    OUTPUT:
    
Linear opacities in the left lower lobe likely represent atelectasis although infection is note entirely excluded .