Society of Nuclear Medicine Procedure Guideline for Gated Equilibrium Radionuclide Ventriculography version 3.0, approved June 15, 2002 A u t h o r s : Jac Scheiner, MD (Brown Medical School, Providence, RI); Albert Sinusas, MD (Yale University School of Medicine, New Haven, CT); Mark D. Wittry, MD (Saint Louis University, St. Louis, MO); Henry D. Royal, MD (Mallinck- rodt Institute of Radiology, St. Louis, MO); Josef Machac, MD (Mount Sinai School of Medicine of New York University, NY); Helena R. Balon, MD (William Beaumont Hospital, Royal Oak, MI); and Otto Lang, MD (Third Medical School, Charles University, Prague, Czech Republic). I. P u r p o s e 6 . Stroke volume ratios B . Common clinical settings in which RVG may The purpose of this guideline is to assist nuclear be useful include: medicine practioners in recommending, perform- 1 . Known or suspected coronary artery disease ing, interpreting, and reporting the results of gated ( C A D ) equilibrium radionuclide ventriculography. a . CAD without myocardial infarction (MI) b . Remote MI I I . Background Information and Definitions c . Acute MI (however, these patients usu- ally should not undergo exercise stress in Gated equilibrium radionuclide ventriculography the first 48 hours after acute MI) (RVG) is a procedure in which the patient’s red blood cells (RBCs) are radiolabeled and electrocar- 2 . To help distinguish systolic from diastolic diograph (ECG)-gated cardiac scintigraphy is ob- causes of congestive heart failure (CHF) in tained. Single or multiple measurements of left patients with known or suspected CHF and/or right ventricular function are obtained. Al- 3 . Evaluation of cardiac function in patients ternative terminologies for this technique include undergoing chemotherapy gated cardiac blood-pool imaging, multigated ac- 4 . Assessment of ventricular function in pa- quisition (MUGA), and gated equilibrium ra- tients with valvular heart disease dionuclide angiography (RNA). An RVG may be used in the conditions listed Data are collected from several hundred cardiac above for (a) determining long-term progno- cycles to generate an image set of the beating heart sis; (b) assessing short-term risk (e.g., preop- that is presented as a single, composite cardiac cy- erative evaluation); and (c) monitoring re- cle. The method can be used to assess (a) regional sponse to surgery or other therapeutic and global wall motion; (b) cardiac chamber size i n t e r v e n t i o n s . and morphology; and (c) ventricular systolic and diastolic function, including left and right ventric- I V . P r o c e d u r e ular ejection fractions (LVEF and RVEF, respec- tively). An RVG may be acquired at rest, during A . Patient Preparation exercise, or after either pharmacologic or mechan- 1 . R e s t ical interventions. No special preparation is required for a rest- ing RVG. A fasting state is generally pre- ferred. It is not necessary to withhold any I I I . Common Indications medications. The electrodes used for cardiac A . Parameters obtained from RVG include the fol- gating must be placed securely on the skin to l o w i n g : ensure an optimal ECG signal. 1 . Global ventricular systolic function 2 . E x e r c i s e 2 . Regional wall motion The patient should be fasting for at least 3–4 3 . Ventricular volumes (qualitative or quanti- hours before the study and should be both t a t i v e ) hemodynamically and clinically stable. Ex- 4 . Responses of above parameters to exercise ercise stress, in the form of supine or upright or other interventions ergometry, is generally preferred. Patients 5 . Systolic and diastolic function indices who are unable to exercise for noncardiac 2 · RADIONUCLIDE VENTRICULOGRAPHY reasons may undergo pharmacologic stress preclude the performance of a study requiring with a positive inotropic agent. It is recom- physical exercise. A resting 12-lead ECG mended that medications that may alter the should be reviewed before an exercise study. heart rate response be withheld unless medi- C . P r e c a u t i o n s cally contraindicated or the efficacy of the 1 . It is mandatory that Occupational Safety medication is being tested by the exercise test. and Health Administration guidelines for Life support instrumentation and cardiac safe handling of human blood products be resuscitative drugs must be available in the followed at all times when techniques label- immediate vicinity of the stress laboratory. ing autologous RBCs are used. A physician or other personnel trained in 2 . When an in vitro method is used for radiola- advanced cardiac life support (ACLS) must beling autologous RBCs, a fail-safe policy be immediately available during the stress and procedure must be in place and imple- and recovery phases. Continuous, prefer- mented to assure that administration of la- ably 12-lead ECG monitoring must also be beled cells to the wrong patient is prevented. performed throughout all phases of the 3 . Patients with potentially unstable cardiac stress study. Intermittent blood pressure rhythms (e.g., paroxysmal supraventricular measurement and ECG tracings should be or ventricular tachycardia) or implanted de- performed before, during, and in the recov- vices (e.g., implantable defibrillators) may ery phases of the stress study. The patient require special precautions, because heart should be clinically observed during and rate response to exercise may be unpre- immediately after the stress test. Any abnor- d i c t a b l e . malities in symptomatology, hemodynam- D . R a d i o p h a r m a c e u t i c a l s ics, or the ECG should be monitored until re- For the adult, the usual administered activity is s o l v e d . 555–1110 MBq (15–30 mCi) autologous RBCs B . Information Pertinent to Performing the Proce- labeled with Tc-99m using the in vivo, modi- d u r e fied in vivo, or in vitro techniques. The usual An adequate history and cardiovascular exam- administered activity in children is 7–15 ination should be obtained before diagnostic MBq/kg (0.2–0.4 mCi/kg), with a minimum evaluation. Specific areas to be reviewed in- dose of 70–150 MBq (2–4 mCi). The largest ab- clude the indication(s) for testing, medications, sorbed radiation dose to an organ is that to the symptomatology, cardiac risk factors, and heart (about 0.02 mSv/MBq). Tc-99m–labeled prior cardiac procedures (diagnostic or thera- RBCs distribute within the blood-pool with an peutic). The patient’s cardiac rhythm should be estimated volume of distribution of approxi- noted, because marked heart rate variability mately 4%–7% of body weight. The estimated may limit the ability to both perform and inter- biological half-life is approximately 24–30 pret the RVG. Physical limitations may limit or hours. Approximately 25% of the administered Radiation Dosimetry for Adults Radiopharmaceutical Administered Organ Receiving the Effective activity largest radiation dose dose MBq mGy per MBq mSv per MBq (mCi) (rad per mCi) (rem per mCi) Tc-99m labeled 555 – 1110 i.v. 0.023 0.0085 red blood cells1 Heart (15 – 30) (0.085) (0.031) Tc-99m albumin2 370 – 740 i.v. 0.020 0.0079 Heart (10 – 20) (0.074) (0.029) 1ICRP 53, p. 210 2ICRP 53, p. 173 SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL JUNE 2002 · 3 Radiation Dosimetry for Children (5 year old) Radiopharmaceutical Administered Organ receiving the Effective activity largest radiation dose dose MBq mGy per MBq mSv per MBq (mCi) (rad per mCi) (rem per mCi) Tc-99m labeled 7 – 15 i.v. 0.062 0.025 red blood cells1 Heart (0.2 – 0.4) (0.23) (0.093) Tc-99m albumin2 5 – 10 i.v. 0.054 0.023 Heart (0.1 – 0.3) (0.23) (0.085) 1ICRP 53, p. 210 2ICRP 53, p. 173 dose is excreted in the urine in the first 24 diac cycle from a heterogenous popula- hours. A stannous pyrophosphate preparation tion of beats and for retrograde gating for is typically used in most red cell labeling tech- diastolic parameters. niques. The dosage of this preparation may b . Acquisition parameters need to be increased in patients receiving “full- A minimum of 16 frames per R-R interval dose” heparin and in patients in renal failure. are required for an accurate assessment of Labeling is least consistent with the in vivo ventricular wall motion and assessment method, intermediate with the modified in of ejection fraction. A higher framing rate vivo method, and most consistent with the in (32–64 frames per R-R) is preferred for vitro method. Tc-99m–radiolabeled human detailed measurement of diastolic filling serum albumin (HSA) is an alternative to radi- parameters and is required for absolute olabeled RBCs. However, images are usually of volume measurements. Acceptable in- lower quality because of the escape of tracer dices of diastolic function are achievable from the intravascular space and breakdown of at 16 frames per cardiac cycle, if Fourier the albumin, resulting in decreased contrast. curve fitting is employed. E . Image Acquisition Images should be acquired so that the 1 . Rest study heart occupies ~50% of the usable field of a . I n s t r u m e n t a t i o n view. Typical acquisitions are for a total Acquisition is performed by a gamma of 3–7 million counts. Supine imaging is camera interfaced to a dedicated com- performed in a minimum of 3 views to vi- puter. Images may be acquired with ei- sualize all wall segments of the left ven- ther a low-energy all-purpose (LEAP) or tricle. The left anterior oblique (LAO) ac- high-resolution parallel-hole collimator.