RT Journal Article SR Electronic T1 Prone Versus Supine Patient Positioning During Gated 99mTc-Sestamibi SPECT: Effect on Left Ventricular Volumes, Ejection Fraction, and Heart Rate JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 2016 OP 2020 VO 45 IS 12 A1 Wolfgang M. Schaefer A1 Claudia S.A. Lipke A1 Harald P. Kühl A1 Karl-Christian Koch A1 Hans-Juergen Kaiser A1 Patrick Reinartz A1 Bernd Nowak A1 Udalrich Buell YR 2004 UL http://jnm.snmjournals.org/content/45/12/2016.abstract AB Gated myocardial perfusion SPECT allows assessment of left ventricular end-diastolic volume (EDV), left ventricular end-systolic volume (ESV), left ventricular stroke volume (SV), and left ventricular ejection fraction (LVEF). Acquiring images with the patient both prone and supine is an approved method of identifying and reducing artifacts. Yet prone positioning alters physiologic conditions. This study investigated how prone versus supine patient positioning during gated SPECT affects EDV, ESV, SV, LVEF, and heart rate. Methods: Forty-eight patients scheduled for routine myocardial perfusion imaging were examined with gated 99mTc-sestamibi SPECT (at rest) while positioned prone and supine (consecutively, in random order). All parameters for both acquisitions were calculated using the commercially available QGS algorithm. Results: Whereas EDV and SV were significantly lower (P < 0.0004) for prone acquisitions (EDV, 110.5 ± 39.1 mL; SV, 55.9 ± 13.3 mL) than for supine acquisitions (EDV, 116.9 ± 36.2 mL; SV, 61.0 ± 14.5 mL), ESV and LVEF did not differ significantly. Heart rate was significantly higher (P < 0.0001) during prone acquisitions (69.1 ± 10.5 min−1) than during supine acquisitions (66.5 ± 10.0 min−1). Conclusion: The observed position-dependent effect on EDV, SV, and heart rate might be explained by decreased arterial filling and increased sympathetic nerve activity. Hence, supine reference data should not be used to classify the results of prone acquisitions.