Electron-Beam Computed Tomography in the Assessment of Coronary Artery Disease After Heart Transplantation

To the Editor: In their study of electron-beam computed tomography (EBCT) for the assessment of coronary artery disease in heart transplantation, Knollmann et al1 noted a significant discrepancy between the amount of calcification measured by EBCT and that measured by intracoronary ultrasound. In their discussion, they suggest a number of possible explanations for this. However, this discrepancy may be related to the different pathogenesis of intimal and medial calcification.2 Intimal calcification occurs within the perimeter of the internal elastic lamina within the atherosclerotic plaque. It is associated with inflammatory cells, lipids, and vascular smooth muscle cells. In contrast, medial calcification occurs as a separate process in the context of aging (Monckeberg’s sclerosis), end-stage renal disease, neuropathy, diabetes, and a number of rare …