Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable chest radiograph a prominent right upper mediastal contour without loss of right paratracheal stripe , likely due to mediastinal vessels . Heart size is normal . Faint opacifications are noted in bilateral lower lungs with air brochograms in the retrocardiac space likely representing atelectasis , but infectious process is a consideration . No pleural effusion or pneumothorax .
    OUTPUT:
    
Bibasilar opacifications ; in absence of strong concern for pneumonia , likely represent atelectasis .