Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are somewhat low but clear . The cardiomediastinal silhouette and contour are within normal limits . There is no pleural effusion or pneumothorax . Old lateral left eighth rib fracture is again noted . There is atelectasis at the left lung base .
    OUTPUT:
    
No acute cardiopulmonary process .