Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A frontal chest radiograph incompletely imaged , with the right costophrenic angle and left lower lung excluded from the field of view . Multiple sternal wires are intact . A cardiac valve replacement is also seen . The cardiomediastinal silhouette remains enlarged , although it is not optimally evaluated on this exam . Diffusely increased opacity of both lungs is likely due to low lung volumes and positioning .
    OUTPUT:
    
Limited exam . Low lung volumes with probable atelectasis . Followup imaging when the patient is able to cooperate with the exam should be considered .