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 with the exception of trace possible subsegmental atelectasis in the left base . There is no pneumothorax , vascular congestion , or pleural effusion . Prior coronary arterial stenting is unchanged . A hiatal hernia is noted . Mild multilevel thoracic spondylosis is noted .
    OUTPUT:
    
Trace left basilar atelectasis .