Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right infrahilar opacity is unchanged from the immediate prior study and may represent subsegmental atelectasis related to low lung volumes . There is no focal consolidation , pleural effusion , pulmonary edema , or pneumothorax . The cardiomediastinal contour is normal .
    OUTPUT:
    
1 . No acute cardiopulmonary process . 2 . Unchanged right infrahilar opacity compared with ___ , however this finding is new from ___ and older studies and a nonemergent chest CT is recommended for further characterization to exclude a pulmonary nodule .