Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph obtained . The lungs are clear , though low lung volume slightly limits evaluation . Plate - like left mid lung atelectasis is noted . No signs of pulmonary edema . No pleural effusion or pneumothorax . Cardiomediastinal silhouette appears normal .
    OUTPUT:
    
No acute intrathoracic process .