Comparison between ECTb and QGS for assessment of left ventricular function

Abstract

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Objectives: The quantitative gated myocardial single photon emission computed tomography (SPECT) (QGS, Cedars-Sinai Medical Center, Los Angeles, CA) and the Emory Cardiac Toolbox (ECTb, Emory University, Atlanta, GA) have been developed for gated perfusion and used in evaluating global and regional left ventricular function automatically.The aim of our study was to compare the performance of two different software packages for the calculation of ejection fraction (EF), end diastolic volume (EDV) and end sistolik volume (ESV) from gated SPECT studies. Methods: The studies were performed using one day rest/stress 99mTc MIBI protocol. Gated SPECT 99mTc MIBI myocardial perfusion studies were collected and analyzed for 88 patients (mean age: 53.98±11.06; 41 female, 47 male) by a double headed gamma camera (Infinia, GE, Tirat Hacermel, Israel). All data processed on a Xeleris Workstation (version 1.0515, GE medical systems). Results: EF, EDV and ESV were calculated for every patient by using QGS and ECTb (Table 1). All linear regression correlations between ECTb and QGS volume and EF values were strong (p<0.0001), with correlation coefficient of stress r=0.94, r=0.95, r=0.97; rest r=0.95, r=0.97, r=0.97 for EF, EDV and ESV, respectively. When EF, EDV and ESV values of QGS and ECTb compared, EF and EDV values of QGS were significantly lower than ECTb (p<0.05), although there was no statistically significant difference between QGS and ECTb of ESV values (p>0.05) (Table 1). QGS measurements of rest EF values compared with ECHO EF (60.68%±12.00%) and no statistically significant difference was detected (p>0.05). Statistically significant difference was found between ECTb rest EF values ECHO EF values (p=0.02). QGS measurements of EF are not significantly different from ECHO EF values (p>0.05) but ECTb significantly overestimates the ECHO values (p<0.05). Conclusions: As QGS and ECTb behave differently and produce variable results from one another, they should not be used interchangeably.

Table 1: Results of EF, EDV and ESV as calculated by the two methods QGS and ECTb.