Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrate normal cardiomediastinal silhouette . The lungs are clear . There may be trace subsegmental atelectasis in the left base . There is no vascular congestion , pneumothorax , or pleural effusion .
    OUTPUT:
    
Left basilar atelectasis . No acute cardiopulmonary process .