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Handbook of Nuclear Cardiology. Cardiac SPECT and Cardiac PET - Libros de Medicina - Cardiologia nuclear - 72,75

Cardiovascular disease continues to be the single greatest cause of morbidity and mortality for men and women in the United States despite the reduction in mortality that has been seen over recent years. This underscores the importance of early identification of patients most at risk for the development of coronary artery disease. Stress myocardial perfusion imaging has been validated as an efficient non-invasive modality in the detection of coronary artery disease (CAD). Although extremely useful, the efficacy of MPI is dependent on appropriate utilization and testing should be performed when the results will significantly affect clinical management. While the evaluation of patients with no known CAD requires careful selection, the identification of “at risk” patients provides important management data.

The incidence of patients with congestive heart failure (CHF) is increasing in the U.S. and now constitutes over five million Americans [1]. Despite advances in treatment strategies, outcomes in patients with CHF are poor, especially in patients with left ventricular function less than 35% (normal 55–75%) [2]. Treatment plans for patients with heart failure are initially based upon whether the heart failure is due to ischemia (ischemic cardiomyopathy) or other causes (non-ischemic cardiomyopathy). This chapter will present the role of nuclear imaging in the evaluation and management of heart failure patients with regards to

The primary goals of noninvasive testing are to aid in the diagnosis of significant CAD as well as to provide adequate risk stratification for future cardiac events including non-fatal myocardial infarction and cardiac death. Exercise tolerance testing (ETT) without imaging for many years has been an important noninvasive tool in the evaluation of patients with suspected or known coronary artery disease (CAD). The exercise tolerance test alone provides both diagnostic and risk stratification information although imaging procedures such as myocardial perfusion imaging enhance both of these endpoints. In selected patients, the ETT alone may be adequate for initial evaluation purposes. This chapter will examine the role of exercise testing as an initial strategy for the evaluation of patients with known or suspected coronary artery disease and place into perspective when ETT with imaging may be preferred.

Patients with coronary artery disease are at increased risk for cardiac events. According to the American Heart Association heart disease and stroke statistics [1], the estimated annual incidence of myocardial infarction (MI) in the United States is 610,000 new attacks and 325,000 recurrent attacks, and 16,300,000 Americans ≥20 years of age have coronary artery disease (CAD). Despite the high prevalence, prognosis for patients with known CAD has improved significantly during the last decades, with the identification and aggressive management of risk factors as well as the wide use of revascularization procedures and anti-platelet agents. As a result, in everyday practice physicians are called upon to evaluate and follow-up a substantial number of patients with known CAD, many of whom have undergone one or more revascularization procedures.

Previous sections have given direction to use of myocardial perfusions in general categories of patients with or without CAD in large patient segments such as those with and without CAD. A major strength of the literature in Nuclear Cardiology is the wealth of data in the assessment of specific patient groups. This chapter will review the use of stress radionuclide perfusion imaging in the diagnosis and risk stratification of specific patient groups such as women, the elderly, diabetic patients and those with chronic kidney disease (CKD).

Alternatives to nuclear cardiology procedures include the use of computed tomography (CT) for cardiac imaging. These procedures are widely available since the advent of the 64-slice CT instrumentation. Assessment of the location and severity of coronary artery calcium (CAC) as well as non-invasive imaging of coronary artery anatomy with coronary CT angiography (CTA) can provide useful information in patients with suspected CAD. This chapter will discuss CAC and coronary CTA imaging, their indications and relevance to nuclear cardiology procedures.

Although magnetic resonance imaging has been available for many years, the cardiac applications have grown and expanded in more recent times. The technology is widely available primarily through hospitals with no radiation exposure, giving physicians another important noninvasive imaging modality used for patients with cardiac disease. Cardiac magnetic resonance (CMR) imaging can include the assessment of myocardial structure, function, perfusion and viability. This chapter will examine the information provided by CMR training as well as the appropriateness criteria and guidelines for indications. Finally, the chapter will put in perspective CMR within the arena of other noninvasive diagnostic imaging procedures such as SPECT/PET myocardial perfusion imaging.