Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . A small triangular opacity along the peripheral left midlung is likely an artifact . There is no pulmonary edema or pleural effusions . No pneumothorax is evident . Cardiomediastinal and hilar contours are within normal limits . Air-filled colon is visualized below the left hemidiaphragm . Probable cervical spinal fusion hardware is incompletely imaged in the region of the right neck . Known subcentimeter pulmonary nodules are better characterized on prior CT examination . There is a mild pectus excavatum deformity .
    OUTPUT:
    
1 . No acute cardiopulmonary process . Known subcentimeter pulmonary nodules not well visualized . 2 . Triangular opacity in peripheral left midlung likely artifact . Consider repeat CXR to confirm . 3 . Stable pectus excavatum deformity .