Question
44 y/o female restrained driver s/p motor vehicle crash complaining of chest pain and shortness of breath.
Answer
Answer: Left pleural apical cap.
The Apical Cap
An apical cap is a unilateral or bilateral irregular density over the apex of the lung, generally less than 5mm. The lower border is often sharp but undulating.
Differential diagnosis:
- Trauma: Blunt aortic injury (BAI) or dissection
- Inflammatory: TB or extra-pleural neck abscess
- Post-radiation fibrosis
- Neoplasm
- Vascular abnormalities: e.g.,aortic coarctation with dilated collateral vessels
- Non-specific (most common): Subpleural thickening, scarring, or other diseases; especially common in elderly.
References
Fabian TC, Richardson JD, Smith JS Jr, et al. Prospective study of blunt aortic injury: multi-center trial of the American Association for the Surgery of Trauma. J Trauma 1997;42:374-383.
McLoud TC, Isler RJ, Novelline RA, et al. The apical cap. Amer J Rad 1981; 137:299-306.
Rivas LA, Fishman JE, Munera F, et al. Multislice CT in thoracic trauma. Radiol Clin North Am2003; 41:599-616.