Figure 11a. Acute pulmonary embolism in a patient with a right lung transplant for usual interstitial pneumonitis. (a) Axial chest CT image, obtained more than 12 weeks after lung transplantation, shows fibrosis in the native left lung (black arrow) and acute pulmonary emboli in arteries within the allograft (white arrow). (b) Magnified view of an axial chest CT image demonstrates a central filling defect (arrow) and local distention of a middle-lobe segment of the right pulmonary artery.