Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Lung volumes are slightly low . Lungs are clear except for a questionable 1 cm nodular opacity just below the level of the seventh posterior right rib . No pleural effusion or pneumothorax is seen . There are bilateral shoulder arthroplasties , which are incompletely imaged .
    OUTPUT:
    
No evidence of congestive heart failure . 1 cm nodular opacity in right upper lung , for which further evaluation with shallow oblique radiographs is recommended to differentiate superimposition of normal structures from a true lung nodule .