Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . Aorta is diffusely tortuous . On the lateral view , an area of confluent opacity overlies the lower thoracic spine anteriorly and is probably in the posterior aspect of the left lower lobe . Lungs are otherwise clear , and there are no pleural effusions or acute skeletal findings .
    OUTPUT:
    
Confluent opacity overlying lower thoracic spine , which may represent a focal area of aspiration , atelectasis or developing pneumonia . Followup radiographs would be helpful to document resolution and to exclude the possibility of a lung nodule or mass in this region .