PROCEDURE GUIDELINES Procedure Guideline for Myocardial Perfusion Imaging H. William Strauss, D. Douglas Miller, Mark D. Wittry, Manuel D. Cerqueira, Ernest V. Garcia, Abdulmassi S. Iskandrian, Heinrich R. Schelbert and Frans J. Wackers Stanford University Medical Center, Stanford, California; St. Louis University Health Sciences Center, St. Louis, Missouri; Georgetown University Medical Center, Washington, D.C.; Emory University Hospital, Atlanta, Georgia; Allegheny University of the Health Sciences, Philadelphia, Pennsylvania; University of California Los Angeles School of Medicine, Los Angeles, California; and Yale University School of Medicine, New Haven, Connecticut likely represents scar.* Recording data with both SPECT and Key Words: myocardial perfusion imaging; practice guideline; electrocardiogram (ECG) gating permits evaluation of the heart; infarction; ischemia; technetium; thallium relationship of perfusion to regional function. J NucíMed 1998; 39:918-923 PART III: COMMON INDICATIONS (TABLE 1) PART I:PURPOSE A. Assessment of the (i) presence, (ii) location, (iii) extent and (iv) severity of myocardial ischemia and scar.f The purpose of this guideline is to assist nuclear medicine practitioners in recommending, performing, interpreting and B. Determination of the significance of anatomic lesions reporting the results of myocardial perfusion imaging studies. detected by angiography. C. Assessment of myocardial viability. PART II: BACKGROUND INFORMATION AND PART IV: COMMON CLINICAL SETTINGS FOR DEFINITIONS Myocardial perfusion imaging is a procedure that utilizes an MYOCARDIAL PERFUSION IMAGING intravenously administered radiopharmaceutical to depict the A. Known or suspected CAD. distribution of nutritional blood flow in the myocardium. 1. Diagnose acute or chronic CAD (presence and sever ity). Perfusion imaging is useful to identify areas of relatively or 2. Determine prognosis (risk stratification based on ex absolutely reduced myocardial blood flow associated with tent of myocardium in jeopardy, cavitary dilatation ischemia or scar. The distribution of perfusion following and lung uptake). radiopharmaceutical injection can be assessed at rest, cardio vascular stress or both. These images can be recorded with either single-photon or positron imaging techniques utilizing radiopharmaceuticals that are extracted and retained for a TABLE 1 Summary of Clinical Indications for Myocardial Perfusion Imaging variable period of time by the myocardium. The relative regional distribution and clearance of a radiopharmaceutical in •Diagnosis of coronary artery disease the myocardium can be recorded with planar or tomographic -presence single-photon techniques or quantitated using positron imaging -location (coronary territory) techniques. The data can be analyzed utilizing visual inspection -extent (number of vascular territories involved) and/or by quantitative techniques. Some Food and Drug Ad- ministration-(FDA-)approved radiopharmaceuticals employed •Assessment of the degree of coronary stenosis and impact on regional for myocardial perfusion imaging include (a) single-photon perfusion tracers 20l"n and the WrnTc-labeled radiopharmaceuti •Assessment of myocardial viability cals such as sestamibi, tetrofosmin and teboroxime and (b) the positron-emitting tracer 82Rb. -ischemia versus scar -prediction of improvement in function following revascularization Patients with significant coronary artery stenosis due to abnormal coronary vasoreactivity or obstructive coronary artery •Risk assessment (prognosis) in patients disease (CAD) have a zone of diminished radiopharmaceutical -after myocardial infarction concentration in the area of decreased perfusion. If this area of -preoperative for major surgery who may be at risk for coronary events decreased tracer concentration is worse when the tracer is administered during stress than when the tracer is administered •Monitoring of treatment effect -after coronary revascularization at rest, the zone of decreased tracer concentration is most likely -medical therapy for congestive heart failure or angina due to ischemia. If the area of diminished tracer concentration -lifestyle modification remains unchanged, even after injection at rest, the lesion most For correspondence or reprints contact: Wendy J.M. Smith, Director of Health Care Policy, Society of Nuclear Medicine, 1850 Samuel Morse Dr., Reston, VA 20190-5316, or by e-mail at [email protected]. "Depending on the clinical circumstance, such fixed abnormalities may represent Note: All 26 SNM-approved procedure guidelines are available on the Society's home high-grade obstruction to zones of viable, hibernating myocardium. When 201T1is used page. We encourage you to download these documents via the Internet at www. as the radiopharmaceutical, delayed imaging may be useful to distinguish these lesions snm.org. If you would like information on the development process of this guideline or from scar. When "Tc-sestamibi is used as the radiopharmaceutical, administering to order a compendium of all 26 procedure guidelines for $20.00, contact Marie Davis, nitroglycerin prior to injection at rest may help make this distinction. Society of Nuclear Medicine, at (703) 708-9000, ext. 250, or by e-mail at TScar (fibrosis) is often due to infarction. However, similar fixed abnormalities may be [email protected]. seen in patients with cardiomyopathy. 918 THEJOURNALOFNUCLEARMEDICINE•Vol. 39 •No. 5 •May 1998 3. Differentiate between coronary and noncoronary eti TABLE 2 ologies in patients with acute chest pain syndromes Modalities for Stress Myocardial Perfusion Imaging seen in the emergency room. •Exercise Stress B. Follow-up of patients with known CAD. -submaximal Evaluate the immediate and long-term effects of: -symptom limited 1. Revascularization procedures (such as coronary artery -maximal bypass grafting, angioplasty, etc.) in patients with recurrent symptoms. •Pharmacologie Stress 2. Medical or drug therapy. -vasodilators 3. Dietary and lifestyle modifications. adenosine C. Known or suspected congestive heart failure. dipyridamole Differentiate ischemie from idiopathic cardiomyopathy. -Ino/chronotopic arbutamine PART V: PROCEDURE dobutamine A. Patient Preparation dobutamine + atropine 1. Rest Injected Myocardial Perfusion Imaging A fasting state is generally preferred (but not neces sary) prior to rest myocardial perfusion imaging. It is of the radiopharmaceutical to reverse the effects of not generally necessary to withhold medications prior the vasodilator. This is not required for adenosine to perfusion imaging. Good intravenous access is due to its short duration of action, required for the administration of the radiopharma- b. Ino/chronotropic adrenergic agents may be adminis ceutical. Radiopaque objects in the area of the thorax tered to increase myocardial oxygen demand (i.e., should be removed prior to imaging; implanted ra- dobutamine, arbutamine). Drugs that may blunt the diopaque objects (metal, silicone, etc.) should be chronotropic response to adrenergic stimulant stress noted as potential attenuators of cardiac activity. with dobutamine or arbutamine should be noted (i.e., 2. Exercise (All stress procedures must be supervised by beta-adrenergic blocking agents). In some patients a qualified health care professional and performed in atropine may be required to increase the heart rate accordance with American Heart Association/Ameri response from dobutamine. Patients should be fast can College of Cardiology guidelines.) ing for a minimum of 4 hr prior to pharmacologie A fasting state is recommended for a minimum of 4 stress testing. Although these agents are in routine hr prior to the stress study. In general, patients clinical use for this indication, they have not re undergoing a stress study should be hemodynamically ceived FDA approval for this specific purpose. and clinically stable for a minimum of 48 hr prior to B. Information Pertinent to Performing the Procedure testing. Patients who are unable to exercise for non- A cardiovascular medical history and cardiorespiratory cardiac reasons (e.g., severe pulmonary disease, ar examination, including baseline vital signs, should be thritis, amputation, neurological disease, etc.) may be obtained prior to stress studies. Specific areas in the stressed pharmacologically with drugs designed to medical history requiring attention are the indication cause coronary hyperemia or increased cardiac work. for the examination, medications, symptoms, cardiac In patients who are capable of performing adequate risk factors and prior diagnostic or therapeutic proce exercise stress, exercise is generally preferred. If not dures. A 12-lead ECG should be reviewed for evidence medically contraindicated, it is recommended that of acute ischemia, arrhythmia or conduction distur medications such as beta-blocking drugs that may bances (i.e., left bundle branch block) prior to stress alter the heart rate and blood pressure (BP) response myocardial perfusion imaging. Diabetic patients re to exercise be withheld for diagnostic studies. A quiring insulin should be evaluated on a case-by-case secure intravenous line should be established for the basis to optimize diet and insulin dosing on the day of administration of the radiopharmaceutical during the examination. stress. Patients undergoing exercise stress should C. Precautions/Contraindications wear comfortable clothing and walking shoes. 1. Exercise Stress 3. Pharmacologie Stress (see Table 2.) The relative contraindications to exercise