Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . No focal consolidation , pleural effusion , pneumothorax , or pulmonary edema . The heart is normal in size . The left main pulmonary artery appears slightly prominent , but is not overtly enlarged . Calcifications of the aortic knob are mild . The mediastinum is not widened . The left hemidiaphragm is elevated , likely secondary to overdistension of the stomach . Mild multi - level degenerative changes of thoracic spine noted .
    OUTPUT:
    
No acute intrathoracic process .