Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright view of the chest demonstrates low lung volumes which accentuate bronchovascular markings . Bibasilar opacities likely represent atelectasis . Hilar and mediastinal silhouettes are unremarkable . Heart size is top normal . There is no pneumothorax . No pulmonary edema . Partially imaged upper abdomen is unremarkable .
    OUTPUT:
    
Low lung volumes . Bibasilar atelectasis . No evidence of acute cardiopulmonary process .