Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacities in the left lung base most likely represent atelectasis ; otherwise , the lungs are clear without infilatrate , pleural effusion or pneumothorax . The cardiac and mediastinal contours are normal . There is no free air beneath the right hemidiaphragm .
    OUTPUT:
    
No acute cardiopulmonary process .