Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest demonstrate a linear opacity at the left lung base , which was worse ___ year ago . There is no dense consolidation or pleural effusion . The heart and mediastinum are normal . There is no pneumothorax .
    OUTPUT:
    
Linear opacity in left lower lung zone was worse ___ year ago , and could represent sequela of prior infection , recrudencense of infection , or atelectasis .