Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear without focal opacities , pleural effusion or pneumothorax . The cardiac and mediastinal contours are stable , however , prominence of the pulmonary arteries persists .
    OUTPUT:
    
Clear lungs with no acute intrathoracic process . Prominence of the pulmonary arteries may indicate pulmonary arterial hypertension .