Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Opacity in the medial right lower hemithorax likely reflects volume loss in the right middle lobe seen on prior CT although pneumonia can not be excluded . No edema , effusion , or pneumothorax . Heart size is normal . Mediastinal contours are unchanged . A hiatal hernia is small . Rib fractures on the right are similar in appearance . Incompletely imaged right humerus fixation hardware .
    OUTPUT:
    
Right middle lobe probable atelectasis , although pneumonia can not be excluded . Hiatal hernia .