Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Heart size is normal . Mediastinal contours are unremarkable , though the superior mediastinum is not well assessed as the patient 's chin obscures this region . Tracheostomy tube is in unchanged position . Hilar contours are normal . There is no pulmonary edema . Minimal blunting of the left costophrenic angle may suggest a small pleural effusion . Retrocardiac patchy opacity and minimal right basilar opacity likely reflect atelectasis . No pneumothorax is identified but the apices are not well assessed due to the patient 's chin and soft tissues of the neck obscuring these regions . There is no acute osseous abnormality .
    OUTPUT:
    
Limited assessment . Bibasilar patchy opacities likely reflect atelectasis in the setting of low lung volumes , but infection or aspiration can not be excluded completely .