Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Ap and lateral views of the chest provided . There is a large left - sided pleural effusion , which is likely decreased since comparison study within the limitations of different patient position . Right lung is clear . No pneumothorax . Incomplete evaluation of the left cardiomediastinal silhouette due to this effusion
    OUTPUT:
    
Large left - sided pleural effusion is likely decreased since chest radiograph ___ . However , given difference in patient positioning between these two studies it is difficult to accurately assess .