Keywords: Apical cap, dissection, blunt aortic injury, chest xray, radiology (PubMed Search)
44 y/o female restrained driver s/p motor vehicle crash complaining of chest pain and shortness of breath.
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.
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.