Version July 2025
The definition of each symbol should be understood as being preceded by an introductory qualifying word or phrase such as "changes indicative of," "opacities suggestive of," or "suspect."
aa: atherosclerotic aorta; at: significant apical pleural thickening; ax: coalescence of small opacities; bu: bulla(e); ca: cancer, thoracic malignancies excluding mesothelioma; cg: calcified non-pneumoconiotic nodules (eg, granuloma) or nodes; cn: calcification in small pneumoconiotic opacities; co: abnormality of cardiac size or shape; cp: cor pulmonale; cv: cavity; di: marked distortion of an intrathoracic structure; ef: pleural effusion; em: emphysema; es: eggshell calcification of hilar or mediastinal lymph nodes; fr: fractured rib(s) (acute or healed); hi: enlargement of non-calcified hilar or mediastinal lymph nodes; ho: honeycomb lung; id: ill-defined diaphragm border; ih: ill-defined heart border; kl: septal (Kerley) lines; me: mesothelioma; pa: plate atelectasis; pb: parenchymal bands; pi: pleural thickening of an interlobar fissure; px: pneumothorax; ra: rounded atelectasis; rp: rheumatoid pneumoconiosis; tb: tuberculosis; od: other disease or significant abnormality.