Evaluation of left ventricular ejection fraction by the quantitative algorithms QGS, ECTb, LMC and LVGTF using gated myocardial perfusion SPECT: investigation of relative accuracy.
OBJECTIVE
To compare the quantitative algorithms Emory Cardiac Toolbox (ECTb), quantitative gated SPECT (QGS), layer of maximum counts (LMC), and left ventricular global thickening fraction (LVGTF) using gated myocardial tomography in the calculation of the left ventricular ejection fraction using the regression without truth (RWT) technique.


METHODS
Seventy-four consecutive patients were included in the study (59 males). All patients underwent stress-rest myocardial perfusion SPECT using Tc-tetrofosmin. Analysis of variance (ANOVA), the paired Student's t-test, the Pearson correlation coefficient and Bland-Altman were used for comparing the methods. The relative accuracy was performed by RWT.


RESULTS
ANOVA revealed a significant difference among the methods in calculating the ejection fraction. RWT showed that ECTb and QGS outperformed the other two methods. The ECTb was slightly better than QGS, and LMC was slightly better than LVGTF. QGS and ECTb achieved good correlations in end diastolic volume, end systolic volume and ejection fraction measurements. One-way ANOVA demonstrated that QGS was the only software program affected by the category of the perfusion summed stress score (SSS), P=0.038. The ejection fraction determined by the QGS, ECTb and LVGTF methods correlated significantly with defect size (r=0.545, P<0.0001; r=0.530, P<0.0001; and r=0.419, P<0.0001, respectively), but the LMC method was not significantly correlated (r=0.216, P=0.067).


CONCLUSIONS
There was a considerable variation among the quantitative gated SPECT methods in the evaluation of the ejection fraction. RWT revealed that the ECTb and QGS outperformed the other two methods with respect to the bias and precision of the measurements. Pair-wise correlations of the four methods ranged from mild to good with large agreement limits. Results of RWT provided important information in ranking the quantitative gated SPECT methods.
Nuclear Medicine Department, Faculty of Medicine, Kuwait University, Faculty of Science, Cairo University, Egypt. magdy_khalil@hotmail.com
Magdy Mohamed
MM
Khalil
Abdelhamid
A
Elgazzar
Wafaa
W
Khalil
D000465:Algorithms; D001185:Artificial Intelligence; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D012986:Software Validation; D013318:Stroke Volume; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*