AUTOMATIC QUANTIFICATION OF EJECTION FRACTION FROM GATED MYOCARDIAL PERFUSION SPECT

We have developed a completely automatic algorithm to quantitatively m easure left ventricular ejection fraction (LVEF) from gated Tc-99m-ses tamibi myocardial perfusion SPECT images. Methods: The algorithm opera tes in the three-dimensional space and uses gated short-axis image vol umes. It segments the left ventricle (LV), estimates and displays endo cardial and epicardial surfaces for all gating intervals in the cardia c cycle, calculates the relative left ventricular cavity volumes and d erives the global EF from the end-diastolic and end-systolic volume, a ll without operator interaction. The algorithm for measuring LVEF was tested in 65 clinical patients undergoing 16-interval and 8-interval r est-gated SPECT and validated against first-pass radionuclide ventricu lography. Results: Automatic segmentation and contouring of the LV was successful in 65/65 (100%) of the studies. Agreement between EFs meas ured from 8-interval gated SPECT and EFs calculated from first-pass da ta was high (y = 2.44 + 1.03x, r = 0.909, p < 0.001, s.e.e. = 6.87). A greement between EF values measured from 16-interval and 8-interval ga ted SPECT was excellent (y = -2.7 + 0.97x, r = 0.988, p < 0.001, s.e.e . = 2.65), the latter being on average lower by 3.71 percentage points . Conclusion: Our automatic method is rapid and highly agrees with con ventional radionuclide measurements of EF, thus providing clinically u seful additional information to complement myocardial perfusion studie s.