Recently, several techniques for non-invasive imaging of the coronary artery have emerged as promising alternatives to conventional coronary angiography for the diagnosis of coronary artery stenosis. Such imaging modalities include magnetic resonance imaging, electron-beam computed tomography and multi-slice computed tomography. With these technologies, images can be acquired rapidly with high temporal and spatial resolution. In their current state of development, non-invasive techniques can reliably be used to visualise significant stenosis of the proximal and mid portions of the coronary tree. However, complete assessment can be hindered by calcification in the vessel wall and by motion artefact.