Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low and the patient is significantly rotated . . The endotracheal tube has been removed . A right chest wall port catheter tip terminates at the cavoatrial junction . A focal opacity at the left upper lobe may represent atelectasis , however early infection is also possible . There is no pleural effusion . or pneumothorax . Cardiomediastinal silhouette is mildly enlarged . The imaged upper abdomen is unremarkable .
    OUTPUT:
    
Focal left upper lobe opacity represent atelectasis , however an early focus of infection can not be excluded .