[Use of imaging in the evaluation of heart transplant recipients]

Common complications after heart transplantation include acute rejection and coronary allograft vasculopathy. In order to detect the presence of rejection, tissue Doppler imaging echocardiography provides high accuracy and allows to optimize the timing of endomyocardial biopsies, which remain the cornerstone in rejection diagnosis. Coronary allograft vasculopathy is often a diffuse disease so that it is difficult to recognize by imaging modalities, such as myocardial perfusion scintigraphy, which are based on intra-patient comparison of different areas. Quantitative assessment of the myocardial blood flow by positron emission tomography overcomes this issue. Dobutamine stress echocardiography provides accurate diagnosis as well as useful prognostic information. Nevertheless, intracoronary ultrasound is nowadays considered the gold standard for vasculopathy assessment, since it is able to detect a minimum intimal thickening which represents the early feature of disease. Magnetic resonance represents the most attractive approach, though it has not yet gained widespread clinical use.