Despite advances in the understanding of the pathophysiology of atherosclerosis and an applaudable reduction in cardiovascular mortality over the past 30 years, coronary artery disease (CAD) remains an important cause of mortality and morbidity in the UK. While primary prevention of CAD is a priority for modern medicine, so too is the need for development of non-invasive techniques for imaging of myocardial ischaemia. Radionuclide tests occupy a central position within the cardiac imaging portfolio, and among them myocardial perfusion imaging (MPI) has an obvious place because it is the only widely available and validated method of assessing myocardial perfusion. The aim of this article is to review the literature about the role of tomographic MPI in the diagnosis of CAD in the general population and in specific clinical subsets, comparing it wherever possible with other imaging modalities and to summarise the recommendations from existing guidelines for the use of this technique.

DIAGNOSTIC PERFORMANCE OF TOMOGRAPHIC MYOCARDIAL PERFUSION IMAGING

Coronary angiography and myocardial perfusion

MPI allows direct assessment of myocardial perfusion and therefore has an important role in the diagnosis of CAD in patients presenting with chest pain. An inducible perfusion abnormality indicates impaired perfusion reserve, which in turn usually corresponds to epicardial coronary obstruction. The site, depth, and extent of the abnormality provide diagnostic and management information. Conversely, a normal stress MPI indicates the absence of coronary obstruction and hence of clinically significant disease. A normal perfusion scan does not exclude non-obstructive CAD, but such disease is unlikely to be related to symptoms or to be prognostically important (see article on prognosis by Bateman and Prvulovich on p v10).

Positron emission tomography (PET) is generally considered the gold standard non-invasive technique for the assessment of myocardial perfusion. Although PET may have better accuracy than MPI, its clinical utility is constrained by high cost and poor availability.^1,2 Therefore, MPI is …