Nuclear medicine techniques and magnetic resonance imaging in coronary artery disease.

Primary modalities for non-invasive imaging of coronary artery disease (CAD) and related disorders include nuclear medicine techniques and magnetic resonance imaging (MRI). Nuclear medicine has contributed greatly to the diagnosis of CAD and the assessment of the extent of functional abnormalities. Thallium-201 has a long history as a perfusion agent and is currently also used to study myocardial viability. Developments in radiopharmaceutical chemistry has provided us with 99mTc-labelled agents with better counting statistics and qualities for SPECT-imaging. Other radiopharmaceuticals allow insight in metabolic disorders, hypoxia and disturbance of the adrenergic system of the myocardium. MRI has many unique applications in cardiovascular diseases. This imaging technique provides excellent structural information and, during ECG triggering, fine display of left ventricular function. Current development using intravascular contrast agents will soon lead to the possibility to evaluate myocardial perfusion. Improved techniques to evaluate coronary artery anatomy and flow are currently under clinical study. Although cardiac MRI is an exciting new tool with great potential for the diagnosis of CAD it is presently not considered a valid alternative for nuclear medicine imaging techniques. Important developments in the next lustrum may change this view.