Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal and the pulmonary vasculature is normal . There is no pulmonary edema . The mediastinal and hilar contours are normal . The lung parenchyma is normal , with the exception of a small platelike atelectasis at the left lung base . No pleural effusion or pneumothorax . No pneumonia .
    OUTPUT:
    
Small left basilar atelectasis .