Abstract

Objective: The main goal was to assess the role of pharmacological post-stress SPECT images in the detection of ischemia using mechanical synchrony parameters in a delayed acquisition protocol.

Methods: We performed a retrospective study of 135 patients with myocardial gated SPECT with suspected or known coronary artery disease with ^99mTc SESTAMIBI. The stress acquisition was obtained at least 45 minutes after dipyridamole injection in a 2-day protocol. Left ventricular systolic synchrony between rest and post-stress was compared, according to the presence of perfusion defects.

Results: In 50 cases presenting transient perfusion defects of diverse intensity and extension, no significant differences were observed in bandwidth (BW) and standard deviation (SD) between rest and post-stress, similar to what was observed in cases with fixed defects or with normal perfusion. Fixed defects were associated with larger SD and BW compared to cases with or without transient defects.

Conclusion: SPECT with vasodilator stress and delayed acquisition protocol fails to detect abnormal ventricular synchronism in studies with myochardial ischemia.

Key words: SPECT, myocardial perfusion, contraction synchrony, dipyridamole, sestamibi.