Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright AP views . There are low lung volumes . Exam appears stable from prior . There is a subtle opacity in the right inferior cardiac margin , consistent with known epicardial fat pad . The lungs are otherwise clear . Cardiomediastinal silhouette is stable . There is no pneumothorax or pleural effusion . Visualized osseous structures are unremarkable .
    OUTPUT:
    
No acute cardiopulmonary process .