Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . There are relatively low lung volumes . Given this , no definite focal consolidation is seen . Subtle left base opacity likely represents atelectasis . There is no pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are stable . Evidence of an old right posterior fourth rib fracture is again seen . There may be minimal pleural thickening along the lateral right lower hemithorax , unchanged as compared to the prior radiograph , although not seen on CT from ___ , and may be artifactual .
    OUTPUT:
    
No acute cardiopulmonary process .