Radionuclide imaging.

Recent advances in nuclear cardiology have included the application of radionuclide imaging techniques to the detection of coronary artery disease. Exercise Thallium-201 myocardial imaging has proved a sensitive and specific test for the detection of significant coronary artery disease and allows differentiation between myocardial ischaemia and infarction. Other conditions affecting the myocardium may produce abnormal myocardial images but, with recognition of this and the variations seen in normal subjects, the diagnostic accuracy of Thallium-201 myocardial imaging compares favourably with exercise electrocardiography. The technique is particularly useful where the exercise electrocardiogram is non-diagnostic or equivocal. Preliminary results from application to screening asymptomatic subjects have been encouraging. Radionuclide ventriculography allows the assessment of global and regional left ventricular function. The development of new regional wall motion abnormalities during stress is a highly specific indicator of the presence of myocardial ischaemia, and combined with analysis of the left ventricular ejection fraction response to exercise provides a sensitive test for the detection of significant coronary artery disease. Probability theory allows consideration of the place of these techniques in the investigation of the individual with proven or suspected coronary artery disease.