Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low with mild secondary vascular congestion . There is mild left basal atelectasis and possible trace left pleural effusion . Unchanged atherosclerotic calcification of the aortic arch . There is no evidence of pneumonia or pneumothorax .
    OUTPUT:
    
Mild left basilar atelectasis and possible trace left effusion .