Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided . There is mild left basal atelectasis with probable small left pleural effusion . The right lung is clear . The cardiomediastinal silhouette appears normal . No convincing signs of pneumonia . Imaged osseous structures are intact . No free air below the right hemidiaphragm .
    OUTPUT:
    
Mild left basal atelectasis with small left pleural effusion , not significantly changed from prior exam .