Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable upright frontal view of the chest . Linear bibasilar opacities most likely represent atelectasis . There is no focal opacity , pleural effusion or pneumothorax . Mild cardiomegaly is new since ___ . Mediastinal and hilar contours appear normal . There is no free air beneath the right hemidiaphragm . The soft tissue and osseous structures are unremarkable .
    OUTPUT:
    
Mild cardiomegaly is new since ___ .