Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP chest radiograph is severely rotated , but demonstrates clear lungs . The hilar and mediastinal contours are difficult to evaluate due to rotation , but appears essentially clear . The heart size is normal . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Technically limited study due to severe rotation , with no obvious source for infection .