Effect of patient positioning on the evaluation of myocardial perfusion SPECT
ECG-gated SPECT myocardial perfusion imaging is usually acquired in supine position. However, some patients are not comfortable in this position for a variety of personal or medical reasons. Our aim was to investigate the effect of patient positioning on quantitative SPECT imaging results using normal supine database.
55 patients (mean age 58.5 ± 8.3 years) were enrolled in this prospective study. Each patient had a pair of ECG-gated stress SPECT myocardial perfusion images acquired on two gamma cameras: one in supine position and the other in upright sitting position. Left ventricular (LV) ejection fraction (EF), end-diastolic (ED), and end-systolic (ES) left ventricular volumes (V), LV mass, summed stress perfusion defect score (SSS), and total severity score (TSS) were calculated automatically relative to a supine normal reference database.
There were no significant differences in LVEF using the two cameras (0.65 ± 0.08 vs. 0.66 ± 0.10; P > 0.1). However, EDV, ESV, and LV mass were significantly smaller in sitting position than in supine position (89 vs. 80 ml; 33 vs. 29 ml and 115 vs. 109 ml, respectively, all P < 0.0001). On the other hand, SSS and TSS were significantly higher in sitting position than in supine position (5.16 vs. 8.73 and 166.82 vs. 288.27, both P < 0.0001). Overall, more studies in sitting position were interpreted as abnormal than in supine position (P < 0.05).
Patient positioning has a significant impact on quantitative gated SPECT imaging results. Using a supine normal reference database, SSS and TSS were larger in sitting position than in supine position. Thus, for imaging in sitting position, separate normal limits are required.
KeywordsMyocardial perfusion imaging patient positioning ECG-gated SPECT sitting vs. supine position
Myocardial perfusion imaging
Single photon emission computed tomography
Summed stress score
Total severity score
Left ventricular ejection fraction
Emory cardiac tool box
Body mass index
This article was finalized under the auspices of the “Mentorship at Distance” committee of the Journal of Nuclear Cardiology. The authors gratefully acknowledge the editorial suggestions by Frans J. Th. Wackers, MD, PhD.
The authors have no conflict of interest.
- 5.Iskandrian AE, Heo J, Mehta D, Tauxe EL, Yester M, Hall MB, et al. Gated SPECT perfusion imaging for the simultaneous assessment of myocardial perfusion and ventricular function in the BARI 2D trial: An initial report from the nuclear core laboratory. J Nucl Cardiol 2006;13(1):83-90.CrossRefPubMedGoogle Scholar
- 12.Danias PG, Ahlberg AW, Travin MI, Mahr NC, Abreu JE, Marini D, et al. Visual assessment of left ventricular perfusion and function with electrocardiography-gated SPECT has high intraobserver and interobserver reproducibility among experienced nuclear cardiologists and cardiology trainees. J Nucl Cardiol 2002;9(3):263-70.CrossRefPubMedGoogle Scholar
- 14.Nakazato Ryo, Tamarappoo Balaji K, Kang Xingping, Wolak Arik, Kite Faith, Hayes Sean W, et al. Quantitative upright-supine high-speed SPECT myocardial perfusion imaging for detection of coronary artery disease: Correlation with invasive coronary angiography. J Nucl Med 2010;51(11):1724-31.CrossRefPubMedPubMedCentralGoogle Scholar