blood pool imaging

(redirected from ejection fraction study)

blood pool im·ag·ing

nuclear medicine study using a radionuclide that is confined to the vascular compartment.

blood pool im·ag·ing

(blūd pūl im'ăj-ing)
Nuclear medicine study using a radionuclide that is confined to the vascular compartment.

Blood Pool Imaging

Synonym/acronym: Cardiac blood pool scan, ejection fraction study, gated cardiac scan, radionuclide ventriculogram, wall motion study, MUGA.

Common use

To evaluate cardiac function after a myocardial infarction.

Area of application



Intravenous radioactive material.


Multigated blood pool imaging (MUGA; also known as cardiac blood pool scan) is used to diagnose cardiac abnormalities involving the left ventricle and myocardial wall abnormalities by imaging the blood within the cardiac chamber rather than the myocardium. The ventricular blood pool can be imaged during the initial transit of a peripherally injected, intravenous bolus of radionuclide (first-pass technique) or when the radionuclide has reached equilibrium concentration. The patient’s electrocardiogram (ECG) is synchronized to the gamma camera imager and computer and therefore termed “gated.” For multigated studies, technetium-99m (Tc-99m) pertechnetate is injected after an injection of pyrophosphate, allowing the labeling of circulating red blood cells; Tc-99m sulfur colloid is used for first-pass studies. Studies detect abnormalities in heart wall motion at rest or with exercise, ejection fraction, ventricular dilation, stroke volume, and cardiac output. The MUGA procedure, performed with the heart in motion, is used to obtain multiple images of the heart in contraction and relaxation during an R-to-R cardiac cycle. The resulting images can be displayed in a cinematic mode to visualize cardiac function. Repetitive data acquisitions are possible during graded levels of exercise, usually a bicycle ergometer or handgrip, to assess ventricular functional response to exercise.

After the administration of sublingual nitroglycerin, the MUGA scan can evaluate the effectiveness of the drug on ventricular function. Heart shunt imaging is done in conjunction with a resting MUGA scan to obtain ejection fraction and assess regional wall motion. First-pass cardiac flow study is done to study heart chamber disorders, including left-to-right and right-to-left shunts, determine both right and left ventricular ejection fractions, and assess blood flow through the great vessels. The study uses a jugular or antecubital vein injection of the radionuclide.

This procedure is contraindicated for

  • high alertPatients who are pregnant or suspected of being pregnant, unless the potential benefits of a procedure using radiation far outweigh the risk of radiation exposure to the fetus and mother.
  • high alertPatients with anginal pain at rest or in patients with severe atherosclerotic coronary vessels; dipyridamole testing is not performed in these circumstances.
  • high alertChemical stress with vasodilators in patients having asthma (because bronchospasm can occur).


  • Aid in the diagnosis of myocardial infarction
  • Aid in the diagnosis of true or false ventricular aneurysms
  • Aid in the diagnosis of valvular heart disease and determining the optimal time for valve replacement surgery
  • Detect left-to-right shunts and determine pulmonary-to-systemic blood flow ratios, especially in children
  • Determine cardiomyopathy
  • Determine drug cardiotoxicity to stop therapy before development of congestive heart failure
  • Determine ischemic coronary artery disease
  • Differentiate between chronic obstructive pulmonary disease and left ventricular failure
  • Evaluate ventricular size, function, and wall motion after an acute episode or in chronic heart disease
  • Quantitate cardiac output by calculating global or regional ejection fraction

Potential diagnosis

Normal findings

  • Normal wall motion, ejection fraction (55% to 65%), coronary blood flow, ventricular size and function, and symmetry in contractions of the left ventricle

Abnormal findings related to

  • Abnormal wall motion (akinesia or dyskinesia)
  • Cardiac hypertrophy
  • Cardiac ischemia
  • Enlarged left ventricle
  • Infarcted areas are akinetic
  • Ischemic areas are hypokinetic
  • Myocardial infarction

Critical findings

  • Myocardial infarction
  • It is essential that critical findings be communicated immediately to the requesting health-care provider (HCP). A listing of these findings varies among facilities.

  • Timely notification of a critical finding for lab or diagnostic studies is a role expectation of the professional nurse. The notification processes will vary among facilities. Upon receipt of the critical finding the information should be read back to the caller to verify accuracy. Most policies require immediate notification of the primary HCP, hospitalist, or on-call HCP. Reported information includes the patient’s name, unique identifiers, critical finding, name of the person giving the report, and name of the person receiving the report. Documentation of notification should be made in the medical record with the name of the HCP notified, time and date of notification, and any orders received. Any delay in a timely report of a critical finding may require completion of a notification form with review by Risk Management.

Interfering factors

  • Factors that may impair clear imaging

    • Inability of the patient to cooperate or remain still during the procedure because of age, significant pain, or mental status.
    • Metallic objects within the examination field (e.g., jewelry, body rings), which may inhibit organ visualization and can produce unclear images.
  • Other considerations

    • Conditions such as chest wall trauma, cardiac trauma, angina that is difficult to control, significant cardiac arrhythmias, or a recent cardioversion procedure may affect test results.
    • Atrial fibrillation and extrasystoles invalidate the procedure.
    • Suboptimal cardiac stress or patient exhaustion, preventing maximum heart rate testing, will affect results when the procedure is done in conjunction with exercise testing.
    • Consultation with an HCP should occur before the procedure for radiation safety concerns regarding younger patients or patients who are lactating. Pediatric & Geriatric Imaging Children and geriatric patients are at risk for receiving a higher radiation dose than necessary if settings are not adjusted for their small size. Pediatric Imaging Information on the Image Gently Campaign can be found at the Alliance for Radiation Safety in Pediatric Imaging (
    • Risks associated with radiation overexposure can result from frequent x-ray or radionuclide procedures. Personnel working in the examination area should wear badges to record their level of radiation.

Nursing Implications and Procedure


  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this procedure can assist in assessing the pumping action of the heart.
  • Obtain a history of the patient’s complaints or clinical symptoms, including a list of known allergens, especially allergies or sensitivities to latex, anesthetics, sedatives, radionuclides, or medications used in the procedure.
  • Obtain a history of the patient’s cardiovascular system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Note any recent procedures that can interfere with test results, including examinations using iodine-based contrast medium.
  • Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
  • Obtain a list of the patient’s current medications including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Address concerns about pain related to the procedure and explain that some pain may be experienced during the test, or there may be moments of discomfort. Reassure the patient that the radionuclide poses no radioactive hazard and rarely produces side effects. Inform the patient that the procedure is performed in a nuclear medicine department by an HCP specializing in this procedure and takes approximately 60 min.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Explain that an IV line may be inserted to allow infusion of IV fluids such as normal saline, anesthetics, sedatives, radionuclides, medications used in the procedure, or emergency medications.
  • Instruct the patient to wear walking shoes for the treadmill or bicycle exercise. Emphasize to the patient the importance of reporting fatigue, pain, or shortness of breath.
  • Instruct the patient to remove external metallic objects from the area to be examined prior to the procedure.
  • Instruct the patient to fast and restrict fluids for 4 hr prior to the procedure. Instruct the patient to withhold medications for 24 hr before the test as ordered by the HCP. Protocols may vary among facilities.
  • Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.


  • Potential complications:
  • Although it is rare, there is the possibility of allergic reaction to the radionuclide. Have emergency equipment and medications readily available. If the patient has a history of allergic reactions to any substance or drug, administer ordered prophylactic steroids or antihistamines before the procedure.

  • Establishing an IV site and injection of radionuclides is an invasive procedure. Complications are rare but do include bleeding from the puncture site (related to a bleeding disorder, or the effects of natural products and medications known to act as blood thinners), hematoma (related to blood leakage into the tissue following needle insertion), infection (that might occur if bacteria from the skin surface is introduced at the puncture site), or nerve injury (that might occur if the needle strikes a nerve).

  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
  • Ensure that the patient has complied with dietary and medication restrictions.
  • Ensure that the patient has removed external metallic objects from the area to be examined prior to the procedure.
  • Administer ordered prophylactic steroids or antihistamines before the procedure if the patient has a history of allergic reactions to any substance or drug.
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Have emergency equipment readily available.
  • Record baseline vital signs and assess neurological status. Protocols may vary among facilities.
  • Establish an IV fluid line for the injection of saline, anesthetics, sedatives, radionuclides, or emergency medications.
  • Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still throughout the procedure because movement produces unreliable results.
  • The patient is placed at rest in the supine position on the scanning table.
  • Expose the chest and attach the ECG leads. Record baseline readings.
  • IV radionuclide is administered and the heart is scanned with images taken in various positions over the entire cardiac cycle.
  • When the scan is to be done under exercise conditions, the patient is assisted onto the treadmill or bicycle ergometer and is exercised to a calculated 80% to 85% of the maximum heart rate as determined by the protocol selected. Images are done at each exercise level and begun immediately after injection of the radionuclide.
  • If nitroglycerin is given, an HCP assessing the baseline MUGA scan injects the medication. Additional scans are repeated until blood pressure reaches the desired level.
  • Patients who cannot exercise are given dipyridamole before the radionuclide is injected.
  • Monitor the patient for complications related to the procedure (e.g., allergic reaction, anaphylaxis, bronchospasm).
  • Remove the needle or catheter and apply a pressure dressing over the puncture site.
  • Observe/assess the needle/catheter site for bleeding, hematoma formation, or inflammation.


  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Unless contraindicated, advise patient to drink increased amounts of fluids for 24 to 48 hr to eliminate the radionuclide from the body. Inform the patient that radionuclide is eliminated from the body within 6 to 24 hr.
  • No other radionuclide tests should be scheduled for 24 to 48 hr after this procedure.
  • Evaluate the patient’s vital signs. Monitor vital signs and neurological status every 15 min for 1 hr, then every 2 hr for 4 hr, and then as ordered by HCP. Monitor intake and output at least every 8 hr. Compare with baseline values. Protocols may vary among facilities.
  • Instruct the patient to resume usual dietary, medication, and activity, as directed by the HCP.
  • Observe for delayed allergic reactions, such as rash, urticaria, tachycardia, hyperpnea, hypertension, palpitations, nausea, or vomiting.
  • Instruct the patient to immediately report symptoms such as fast heart rate, difficulty breathing, skin rash, itching, chest pain, persistent right shoulder pain, or abdominal pain. Immediately report symptoms to the appropriate HCP.
  • Monitor ECG tracings and compare with baseline readings until stable.
  • Observe/assess the needle/catheter site for bleeding, hematoma formation, or inflammation.
  • Instruct the patient in the care and assessment of the injection site.
  • If a woman who is breastfeeding must have a nuclear scan, she should not breastfeed the infant until the radionuclide has been eliminated. This could take as long as 3 days. She should be instructed to express the milk and discard it during the 3-day period to prevent cessation of milk production.
  • Instruct the patient to immediately flush the toilet and to meticulously wash hands with soap and water after each voiding for 24 hr after the procedure.
  • Instruct all caregivers to wear gloves when discarding urine for 24 hr after the procedure. Wash gloved hands with soap and water before removing gloves. Then wash hands after the gloves are removed.
  • Nutritional Considerations: Abnormal findings may be associated with cardiovascular disease. Nutritional therapy is recommended for the patient identified to be at risk for developing CAD or for individuals who have specific risk factors and/or existing medical conditions (e.g., elevated low-density lipoprotein [LDL] cholesterol levels, other lipid disorders, insulin-dependent diabetes, insulin resistance, or metabolic syndrome). Other changeable risk factors warranting patient education include strategies to encourage patients, especially those who are overweight and with high blood pressure, to safely decrease sodium intake, achieve a normal weight, ensure regular participation in moderate aerobic physical activity three to four times per week, eliminate tobacco use, and adhere to a heart-healthy diet. If triglycerides are also elevated, the patient should be advised to eliminate or reduce alcohol. The 2013 Guideline on Lifestyle Management to Reduce Cardiovascular Risk published by the American College of Cardiology (ACC) and American Heart Association (AHA) in conjunction with the National Heart, Lung, and Blood Institute (NHLBI) recommends a “Mediterranean”-style diet rather than a low-fat diet. The new guideline emphasizes inclusion of vegetables, whole grains, fruits, low-fat dairy, nuts, legumes, and nontropical vegetable oils (e.g., olive, canola, peanut, sunflower, flaxseed) along with fish and lean poultry. A similar dietary pattern known as the Dietary Approaches to Stop Hypertension (DASH) diet makes additional recommendations for the reduction of dietary sodium. Both dietary styles emphasize a reduction in consumption of red meats, which are high in saturated fats and cholesterol, and other foods containing sugar, saturated fats, trans fats, and sodium.
  • Social and Cultural Considerations: Numerous studies point to the prevalence of excess body weight in American children and adolescents. Experts estimate that obesity is present in 25% of the population ages 6 to 11 yr. The medical, social, and emotional consequences of excess body weight are significant. Special attention should be given to instructing the child and caregiver regarding health risks and weight control education.
  • Recognize anxiety related to test results, and be supportive of fear of shortened life expectancy. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services. Provide contact information, if desired, for the American Heart Association ( or the NHLBI (
  • Recognize anxiety related to test results, and be supportive of perceived loss of independent function. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be needed to evaluate and determine the need for a change in therapy or progression of the disease process. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

  • Related tests include antiarrhythmic drugs, apolipoprotein A and B, AST, ANP, blood gases, BNP, calcium, ionized calcium, cholesterol (total, HDL, and LDL), CRP, CT cardiac scoring, CK and isoenzymes, culture viral, echocardiography, echocardiography transesophageal, ECG, exercise stress test, glucose, glycated hemoglobin, Holter monitor, homocysteine, ketones, LDH and isoenzymes, lipoprotein electrophoresis, magnesium, MRI chest, MI infarct scan, myocardial perfusion heart scan, myoglobin, pericardial fluid analysis, PET heart scan, potassium, triglycerides, and troponin.
  • Refer to the Cardiovascular System table at the end of the book for related tests by body system.