Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are slightly low . The cardiomediastinal silhouette and pulmonary vasculature a similar to the prior examination , and unremarkable , accounting for low lung volumes . Midline sternal wires are intact and well aligned . Mediastinal clips and anastomotic markers are noted . The lungs are clear . There is no pleural effusion or pneumothorax . Bilateral shoulder prostheses are partially imaged .
    OUTPUT:
    
No acute intrathoracic abnormality .