Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Previously seen PICC is no longer present . There is subtle patchy opacity at the left lung base and underlying infection may be present . No pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are unremarkable . Hilar contours are stable .
    OUTPUT:
    
Patchy left base opacity , new since the prior study , could be due to infection .