Coronary arteries.

Conventional coronary angiography (CA) is the standard of excellence for the evaluation of coronary artery disease. However, non-invasive imaging modalities have developed that can play an important clinical role in the diagnosis. Magnetic resonance imaging (MRI) can offer a comprehensive evaluation of the heart and the coronary arteries by virtue of its high soft tissue contrast capabilities, double-oblique tomographic sections and the possibility of quantifying physiological parameters without need of ionizing radiation. Magnetic resonance coronary arteriography (MRCA) using breath-hold and free-breathing techniques has been investigated but is still in the experimental phase; its precise role for the assessment of coronary stenosis must still be identified. Nonetheless, MRCA has proven clinically relevant in determining the course of anomalous coronary arteries and the patency of coronary artery bypass grafts. Novel intravascular contrast agents promise faster coverage of the cardiac anatomy and may provide a long-awaited boost for MRCA. Contrast-enhanced electron-beam computed tomography (EBT), another competing imaging modality, is now being subjected to widespread evaluation following initially encouraging results.