Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Semi-upright bedside AP radiograph of the chest demonstrates considerably lower lung volumes when compared to prior studies . There are bilateral lower lobe heterogeneous opacities obscuring the diaphragmatic contours . The lungs are otherwise clear . There is no pneumothorax or pleural effusion . The hilar and cardiomediastinal contours are normal . A right chest wall Port - A - Cath terminates at the cavoatrial junction .
    OUTPUT:
    
Bilateral lower lobe airspace opacities which may simply represent atelectasis , however , in the setting of concern for infection , pneumonia can not be excluded .