Several factors have led to the ultimate success of lung transplantation, including (1) improved recipient assessment and selection, (2) improved intensive care unit care, (3) better understanding of the mechanism of rejection and refinements in immunosuppressive regimens, (4) improved prevention, diagnosis, and treatment of infections, (5) improved surgical techniques to overcome problems of airway ischemia, and (6) development of effective rehabilitation programs.

Major challenges remain, however. ^{18 and 19} The major obstacle to the growth of lung transplant programs is the limited supply of suitable donors. Only 20% to 30% of multi-organ donors have lungs that are suitable for transplantation because of the high incidence of complications such as aspiration pneumonia, atelectasis, and the pulmonary edema associated with donor brain death. More recently, the harvest of lower lobes from two living donors for double lung transplant has been performed successfully by several groups, thereby shortening the wait for a suitable donor.⁶⁷ The development of obliterative bronchiolitis in up to 50% of long-term survivors remains another major challenge. Obliterative bronchiolitis is the major factor affecting long-term survival and quality of life. ^{32 and 35}

Several complications pertain specifically to lung transplant recipients, including airway ischemia, reperfusion edema, infections, acute rejection, obliterative bronchiolitis and other postoperative problems related to surgical technique and immunosuppressive therapy. Imaging procedures play an important role in the diagnosis and management of these problems. This article focuses on the imaging appearance of these complications.*