Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . The known nodule in the right lower lobe is not clearly visualized on chest radiograph . The lungs appear clear without signs of pneumonia or CHF . No effusion or pneumothorax . Cardiomediastinal silhouette is normal . Bony structures are intact . Mural calcification along the aortic knob noted . No free air below the right hemidiaphragm .
    OUTPUT:
    
Known right lower lobe lung nodule not clearly visualized . No signs of pneumonia or other acute intrathoracic process .