Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a hyperdense nodular opacity projecting over the left lung base that may represent a bone island in a rib vs . a calcified granuloma in the lung . The lungs and pleural spaces are otherwise clear without evidence of pneumothorax or pleural effusions . The heart is normal in size . There is no evidence of pneumoperitoneum . Osseous structures are grossly intact .
    OUTPUT:
    
No acute intrathoracic process .