Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Previously seen left base opacity has resolved in the interval . Subtle patchy opacity projecting over the anterior lower lung on the lateral view , not well appreciated on the frontal view , could represent a small focus of infection or atelectasis . No pleural effusion or pneumothorax is seen . Cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
Subtle focal patchy opacity projecting over the anterior lower lung on the lateral view , and not well substantiated on the frontal view , could represent a small focus of infection or atelectasis .