Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear without focal opacity , pulmonary edema , pleural effusion or pneumothorax . The mediastinal contours are normal . There is a ventriculoperitoneal shunt . Mild upper lumbar vertebral body compression deformity is unchanged since ___ .
    OUTPUT:
    
No acute intrathoracic process .