Study of the influence of cycles/frame numbers in LVFE (left ventricular function ejection) in Gated-SPECT studies

Abstract

Introduction - Gated-Single Photon Emission Computed Tomography (Gated-SPECT) is being increasingly used for the simultaneous evaluation of myocardial perfusion and left ventricular function, at rest and under stress. The aim of this study is to investigate the influence of the number of cardiac cycles (cycles/frame) and total counts per acquisition in the calculation of LVEF (left ventricular ejection fraction). Material and methods - from our pool of routine clinical referrals for Gated-SPECT we studied 35 individuals (last of each day) twice after stress and twice at rest, following a one day stress-rest protocol. The two studies under stress were obtained with 25 cycles/frame (S-25) one of them and the other with 50 cycles/frame (S-50), whilst at rest one was performed with 25 cycles/frame (R-25) and the other with 12 cycles/frame (R-12). The statistical analysis was carried out with SPSS version-14. Results - There were no statistically significant differences between LVEF values under stress (S-25 versus S-50; p=0.504). There was also no statistically significant difference between the LVEF values calculated at rest (R-25 versus R-12; p=0.243). Conclusion - In our patient sample, the number of cycles/frame and total counts per acquisition did not interfere significantly in the calculation of LVEF either under stress or at rest, using Gated-SPECT.

Keywords

• Gated-SPECT, fracção de ejecção ventricular esquerda, volume telediastólico, volume telesistólico