Cardiac CT of the transplanted heart: Indications, technique, appearance, and complications

Effective antirejection therapy and infection control have significantly improved the long-term survival of heart transplant recipients, but coronary allograft vasculopathy remains an important limiting factor. Most heart transplant recipients undergo annual coronary angiography for the detection of allograft vasculopathy, which is often clinically silent. Angiography allows detection of vasculopathy only indirectly, with depiction of the lumen, and does not depict the wall thickening and intimal hyperplasia that typify this disease; the procedure also is invasive and is associated with a 1%-2% risk of complication. In contrast, electrocardiographically gated multidetector computed tomography (CT) can provide a comprehensive and noninvasive evaluation of the transplanted heart in a single study. Cardiac CT enables evaluation of the coronary artery lumen and wall and thus may be used for screening, diagnosis, grading, and follow-up of coronary allograft vasculopathy. It also may be used to detect other posttransplantation complications, such as malignancy and infection, and to assess cardiac and vascular anastomoses and cardiac function. However, special strategies may be needed to reduce the transplant heart rate so as to obtain images of diagnostic quality.