Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . There is no focal opacity , pulmonary edema , focal opacity , pleural effusion or pneumothorax . Left retrocardiac opacity represents a ventral hernia related to a prior Nissen fundoplication . The aorta is tortuous . Top normal heart size . Left hilar nodular opacities appear unchanged since ___ . There is no pneumothorax .
    OUTPUT:
    
Low lung volumes .