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KEY POINTS
There is abundant literature support for nuclear cardiac imaging in specific populations, with value for both diagnosis and risk stratification.
Nuclear cardiac imaging provides important diagnostic and risk stratification data with both single-photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI), while abnormal myocardial blood flow (MBF) assessment identifies microvascular disease with independent risk of coronary events.
Data on MBF are increasingly important in specific populations, such as diabetics and women.
In diabetic patients, patients with normal exercise SPECT carry a low risk of coronary events, while those with abnormal MBF are at the highest risk of events.
Overall, MPI in female patients provides similar diagnostic and risk stratification data in male patients, while MBF data provide further risk stratification especially in nonobstructive disease states.
Renal failure patients are at high risk for cardiac events, and myocardial perfusion data provide important risk stratification.
In the elderly population, exercise testing alone does not provide adequate discrimination between normal and abnormal results, while SPECT and PET MPI provide incremental prognostic value.
In obese patients, the use of attenuation correction, alternate patient positioning, and altered radiopharmaceutical dosing/protocols is recommended, which will then provide similar clinical information to that obtained in a nonobese population.
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Previous chapters have demonstrated the important role of myocardial perfusion imaging (MPI) for the diagnosis and risk stratification of epicardial coronary artery disease (CAD) in the general population of patients with known or suspected CAD. Of importance are patient groups that are at higher risk of CAD and adverse outcomes, in which MPI can identify both low- and high-risk groups. There is a robust literature validating the use of MPI in these more specific patient cohorts. This chapter will describe the value of MPI for the assessment of CAD and risk stratification in special populations consisting of diabetic patients, women, patients with chronic renal disease, obese patients, and the elderly. These five patient populations present their own unique challenges from a diagnostic, as well as prognostic, perspective. In the past, the role of nuclear imaging has primarily focused upon identifying patients at risk for epicardial CAD and its consequences. There is a growing body of literature demonstrating that many patients in these groups have disease processes that are more extensive than epicardial disease alone. At the same time, an emerging role for nuclear perfusion imaging is in the evaluation of atherosclerotic disease of the coronary microvasculature (coronary microvascular disease, CMD) through the assessment of myocardial blood flow (MBF) and myocardial blood flow reserve (MBFR, also known as coronary flow reserve [CFR]). While the primary purpose of this chapter is to present data on the role of nuclear cardiology for epicardial CAD, its new role expanding beyond the microvascular disease for each patient group will also be discussed.
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Cardiac Microvascular Disease: Clinical Consequences and its Importance in Special Populations
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Chest pain without obstructive coronary ...