Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear without focal opacity , pulmonary edema , pleural effusion or pneumothorax . Known pectus excavatum obscures the right heart border . The heart size is normal . The mediastinal contours are stable . There is no free air beneath the diaphragm .
    OUTPUT:
    
No acute intrathoracic process .