The impact of acquisition protocol on the incidence of patient motion in 99mTc based myocardial perfusion SPECT

BACKGROUND: Myocardial perfusion single photon emission computed tomography (SPECT) artefacts introduced as a result of patient motion are known to produce artefacts that mimic the appearances of coronary artery disease. The advent of 99mTc based radiopharmaceuticals permits greater flexibility in patient scheduling, but variable physical demands of protocols may be associated with variations in the likelihood of patient motion. METHODS: A prospective cross-sectional study of 177 myocardial perfusion SPECT patients using 99mTc tetrofosmin was used to compare the incidence of visually detectable motion for three protocol variations. The rotating cinematic display and sinograms of the datasets were visually assessed by two experienced technologist observers blinded to the second observer's responses and the clinical outcome. RESULTS: Among the 354 individual studies analysed, 43.8% contained visually detectable motion. 36.2% of rest studies demonstrated visually detectable motion compared to 51.4% for stress (P<0.05). Fifty per cent of 1 day rest/stress studies demonstrated motion, 39.3% of 2 day rest/stress studies demonstrated motion, and 46.8% of 2 day stress/rest studies demonstrated motion. CONCLUSION: One day 99mTc based myocardial perfusion SPECT studies are 1.3 times more likely to contain motion than the 2 day rest/stress protocol. The 2 day stress/rest protocol is 1.2 times more likely to contain motion than the 2 day rest/stress. The stress study is 1.4 times more likely to contain motion than the rest study while the stress study performed first in the sequence is 1.4 times more likely to contain motion than the stress study performed second. The 2 day rest/stress protocol is the preferred protocol to minimize patient motion.