Can the estimation of ejection fraction during gated single photon emission computed tomography at rest add information to the cardiac perfusion study?
Left ventricular function is an important prognostic indicator in patients with coronary artery disease. The electrocardiogram gated, myocardial, single photon emission tomography (SPECT) program is coming into wide use. This program permits measurement of end diastolic volume, end systolic volume, and ejection fraction. This study was designed to show whether the measurement of ejection fraction by using 99mTc tetrofosmin gated SPECT at rest could give additional information to the interpretation of perfusion. Exercise 99mTc tetrofosmin SPECT and gated 99mTc tetrofosmin SPECT at rest were performed in 33 patients with or suspected of having coronary artery disease. Left ventricular ejection fraction was calculated from reconstructed gated SPECT at rest with a software quantitative gated SPECT. The results showed a poor correlation between segmental ejection fraction and segmental perfusion in stress and rest. There was an increasing probability of reversibility as the ejection fraction increased, while there was a greater chance of a fixed defect as the ejection fraction decreased. It is concluded that gated SPECT using 99mTc tetrofosmin provides clinically satisfactory functional data that, in combination with the perfusion information, will improve diagnostic and prognostic accuracy without an increase in cost or radiation dose to patients.