Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright chest radiograph demonstrates adequate lung volumes with bibasilar opacities , right greater than left . The cardiac and mediastinal contours are unchanged , somewhat shifted to the right . The pulmonary vasculature is normal . There is no pneumothorax .
    OUTPUT:
    
Right greater than left basilar opacity , likely reflecting atelectasis , though pneumonia is not excluded .