UMEM Educational Pearls

Category: Trauma

Title: What's wrong with this picture? By John Greenwood, MD

Keywords: Apical cap, dissection, blunt aortic injury, chest xray, radiology (PubMed Search)

Posted: 1/31/2011 by Haney Mallemat, MD
Click here to contact Haney Mallemat, MD

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.