Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with the prior study and allowing for differences positioning , again seen is the small right pleural effusion . As before , the lung contour along the right lateral mid / lower chest wall appears irregular and the presence of a loculated pneumothorax / hydro pneumothorax remains a possibility . Compared with the film from 1 day earlier , there is more pronounced patchy opacity in the right cardiophrenic region . While this could represent atelectasis , it is relatively rounded and raises the possibility of a focus of aspiration or early pneumonic infiltrate . Again seen is minimal atelectasis at the left base . Minimal blunting of left costophrenic angle slightly more pronounced than on the prior study . Doubt overt CHF . A rounded 9 .7 mm density projects over the left proximal humerus . In the absence of known malignancy , this likely represents a bone island .
    OUTPUT:
    
Small right effusion . The possibility of a loculated hydro pneumothorax can not be excluded , though the size is similar to the film from 1 day earlier . Patchy opacity right cardiophrenic region . Differential diagnosis includes a focus of aspiration early pneumonic infiltrate . Minimal blunting of left costophrenic angle . Rounded density left humeral head . Please see comment above .