Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-upright radiograph of the chest demonstrates poor definition of the right heart border , which may be positional . The cardiomediastinal and hilar contours are unremarkable . There is no pneumothorax or pleural effusion .
    OUTPUT:
    
Poor definition of the right heart border may be positional . Consider repeat frontal and lateral radiographs for further evaluation .