Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable view of the chest is compared to prior from ___ . Linear , subsegmental atelectasis seen at the left lung base . The lungs are otherwise clear . Cardiomediastinal silhouette is within normal limits and unchanged . There is no visualized free air below the diaphragms . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
No acute cardiopulmonary process .