Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A central venous catheter terminates in the right atrium . The cardiac , mediastinal and hilar contours appear stable . On the frontal view only there is patchy opacity at the medial left lung base suggesting atelectasis ; developing pneumonia is possible , however .
    OUTPUT:
    
Vague opacity at the left base , atelectasis versus pneumonia ; correlation with pulmonary symptoms is recommended , if any . Short - term follow - up radiographs may be helpful if there is clinical concern for developing infectious process .