Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph was obtained . The lungs are somewhat low in volume , with resultant mild basilar linear atelectasis . Blunting of the costophrenic angles bilaterally is likely due to overlying soft tissues rather than pleural effusion . Mild cardiomegaly persists without overt edema . The mediastinal and hilar contours are otherwise unremarkable .
    OUTPUT:
    
No acute intrathoracic process .