Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is at the upper limits of normal size . The mediastinal and hilar contours appear within normal limits . There are streaky opacities in the left mid lung which appear increased , suggestin opacity superimposed on background scarring . There is also focal opacification of the left lower hemithorax on the lateral view , new since the prior study and projecting primarily over the visualized lower thoracic spine . There is no pleural effusion or pneumothorax . The patient is status post right shoulder hemiarthroplasty .
    OUTPUT:
    
Increased posterior opacification , probably in the left lower lobe , a finding which could be seen with atelectasis , but pneumonia could also be considered in the appropriate setting .