M.H. KHEDR *, M. ABDULLAH**#, A.S. MONEM***
*Biophysics Division, Physics Department, Faculty of Science, Helwan University, Cairo, Egypt
**Arab Contractors Medical Centre, Nuclear Medicine Unit, Cairo, Egypt
***Department of Biophysics, Faculty of Science, Cairo University, Cairo, Egypt
Gated myocardial perfusion SPECT (G-SPECT) is considered as one of the best techniques for the combined evaluation of the myocardial perfusion and the left ventricular ejection fraction (LVEF) within a single study. Sufficient count density in the ciné frames is necessary for best myocardial perfusion images quality and G-SPECT synchronized with the subject’s electrocardio- gram (ECG) to identify the temporal phases of the cardiac cycle. The variation in the cardiac cycle duration may cause fluctuation of the adjacent frames count which compromises the quality of perfusion image and decreases the left ventrecle ejection fraction (LVEF) accuracy. This study investigates the changes that occur in cardiac perfusion imaging and the LVEF accuracy due to the variation in the cardiac cycle duration due to arryhthmia or any gating errors (G.E). This study was performed on fifty-two patients classified into two groups: 35 non-arrhythmic patients (group 1) and 17 arrhythmic patients (group 2). Each patient had two consecutive stress G-SPECT acquisitions: one of them was taken with time-dependent projections (stress SEC), and the other with accepted beats projections (stress AB). LVEF was calculated for both acquisitions, and compared with echocardiogram EF, and their perfusion images were compared with the non-gated SPECT perfusion images (stress N.G). Results. In arrhythmic patients all the myocardial perfusion and function assessed from G-SPECT showed significant changes when compared with non-gated SPECT and echo; non-arrhythmic patients had non-significant changes in contrast and square of different arteries, but other values showed significant differences. Non-gated SPECT and AB-gated SPECT is better than SEC-gated SPECT in the evaluation of the myocardial perfusion or the LVEF, especially for arrhythmic patients.
Key words: G-SPECT, myocardial perfusion, arrhythmia, rejected heart beat, gating errors, flickering artifact, accepted heart beat.
Corresponding author’s e-mail: Mohamadabdullah3785@gmail.com.
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