Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Assessment is limited due to positioning . Allowing for this limitation , there is a vague focal opacity in the left lower lung which was not present in prior torso CT . No other focal opacities are identified . Calcified lymph nodes are seen in the left hilum . Cardiomediastinal and hilar contours are unremarkable . There is no pleural effusion or pneumothorax . Please refer to recent CT for description of no thoracic spine fracture not appreciated in this exam .
    OUTPUT:
    
New vague opacity in the left lower lung was not clearly present in torso CT performed 4 hr prior and may represent a focus of aspiration versus atelectasis .