First-Pass Angiocardiography

First-pass angiocardiography takes place when a bolus of radionuclide is injected intravenously and images are taken as this bolus passes through the heart, lungs, and great vessels. It can provide critical information about the function of the heart. Some of the most important data include left and right ventricular ejection fractions. First-pass studies also can show ejection rates, cardiac output, stroke volumes, and end-diastolic and end-systolic volumes. With this information, physicians can assess the integrity of the intracardiac and heart-lung circulations.1 (Takahashi/p29-31,)

Technetium agents such as MYOVIEW are advantageous because the patient can have a first-pass technique and myocardial perfusion technique with a single injection.1,2 (Takahashi/p30, 36) (Kumita/abstract)

Equilibrium Radionuclide Angiocardiography

The most widely used technique for measuring ventricular function is equilibrium radionuclide angiocardiography (ERNA), also known as multigated blood pool scan (MUGA). In this technique, the concentration of the radionuclide in the blood is first allowed to equilibrate within the circulatory system and then images are taken of the heart.

Because so little of the radionuclide is in the heart in any one contraction, the counts from many contractions must be added together before a usable image can be reconstructed with the computer.

Like first-pass angiocardiography, ERNA or MUGA can be performed while the patient is at rest or during exercise testing. ERNA or MUGA requires a radiopharmaceutical that remains within the blood pool. The blood is withdrawn and incubated with a technetium agent and reinjected. Counts are obtained and a computer then reconstructs the ventricular time/activity curve, ejection fraction, and other functional data for this information.2 (Kumita/abstract)

Gated SPECT

Gated SPECT can be performed as a routine part of MPI without additional injections or image acquisition. The newer computer systems are capable of processing these images rapidly and accurately. Viewing wall motion and thickening from gated SPECT improves recognition of artifacts and attenuation. All of these bits of information improve specificity3,4 (Chou abstract) (Mochizuki/p53,57)

Cardiologists have found that ejection fraction, no matter how it is measured, is the most important parameter for the management and assessment of prognosis in all types of heart disease. By being able to provide simultaneous assessment of perfusion and function using gated SPECT, nuclear cardiology increases its value to clinicians.4,5 (Mochizuki/p53,57) (Everaert/p472,475)

Technetium perfusion agents are used to perform ventricular wall motion evaluation and ejection fraction. Because MYOVIEW is well-retained in the myocardium and has other ideal technetium properties, the nuclear camera can create a gated cardiac image, primarily of the left ventricle, with SPECT scanning. With technetium agents, the ejection fraction is determined by wall motion difference within a complete cardiac cycle.1 (Takahashi/p 29,35-37)

The combined analysis of stress perfusion and wall motion provides a better sensitivity for detecting regional abnormality in the areas with stenotic coronary arteries than either analysis alone.1 (Takahashi/p35)

With the introduction of technetium perfusion agents, both gated SPECT and myocardial perfusion studies can be performed with a single injection of radiopharmaceutical.2 (Kumita/abstract)

Gated MYOVIEW SPECT LVEF

Images provided by Salvador Borges-Neto, MD, FACC, Associate Professor of Medicine and Director of Nuclear Cardiology, Duke University.

References: 1. Takahashi N, Tamaki N, Tadamura E, et al. Combined assessment of regional perfusion and wall motion in patients with coronary artery disease with technetium 99m tetrofosmin. J Nucl Cardiol. 1994;1:29-38. 2. Kumita S, Cho K, Mizumura S, et al. Assessment of left ventricular systolic function derived from ECG-gated myocardial SPECT with 99mTc-tetrofosmin: automatic determination of LV epi- and endocardial surface. Kaku Igaku. 1997;34:237-242. 3. Choi JY, Lee KH, Kim SJ, et al. Gating provides improved accuracy for differentiating artifacts from true lesions in equivocal fixed defects on technetium 99m tetrofosmin perfusion SPECT. J Nucl Cardiol. 1998;5:395-401. 4. Mochizuki T, Murase K, Tanaka H, Kondoh T, Hamamoto K, Tauxe WN. Assessment of left ventricular volume using ECG-gated SPECT with technetium-99m-MIBI and technetium-99m-tetrofosmin. J Nucl Med. 1997;38:53-57. 5. Everaert H, Bossuyt A, Franken PR. Left ventricular ejection fraction and volumes from gated single photon emission tomographic myocardial perfusion images: comparison between two algorithms working in three-dimensional space. J Nucl Cardiol. 1997;4:472-476. 6. Ban K, Nakajima T, Iseki H, Abe S, Handa S, Suzuki Y. Evaluation of global and regional left ventricular function obtained by quantitative gated SPECT using 99mTc-tetrofosmin for left ventricular dysfunction. Intern Med. 2000;39:612-617.