REPEATABILITY OF AUTOMATIC LEFT-VENTRICULAR CAVITY VOLUME MEASUREMENTS FROM MYOCARDIAL PERFUSION SPECT

Background. This study sought to assess the repeatability of automatic quantitative measurements of left ventricular (LV) cavity volumes in a large patient population (N = 926), to correlate those measurements to similarly obtained LV ejection fraction (LVEF) measurements, and to investigate the relationship between ungated and gated volumes. Metho ds. All 926 patients underwent ungated single photon emission computed tomography (SPECT) immediately followed by 8-frame gated SPECT, LV ca vity volumes were automatically measured from ungated (V), summed gate d (SUMV), end-systolic (ESV) and end-diastolic (EDV) images, and LVEFs derived from the latter 2.Results, Repeatability (SUMV vs V) was very good overall (6.4% +/- 6.6%), further improving for volumes >25 mL (5 .7% +/- 5.5%) and >40 mL (5.2% +/- 5.0%), Exponential regression betwe en ESV and LVEF (r = 0.925, SEE = 15.0 mL), EDV and LVEF (r = 0.802, S EE = 24.2 mL), and SUMV and LVEF (r = 0.867, SEE = 19.7 mL) was also v ery good. Summed gated volumes. were closer to ESV than to EDV (43.3% +/- 8.8 % of EDV-ESV range). SUMV <50 mt and SUMV >110 mL were good su bstitutes for LVEF >50% and LVEF <40% (93.4% and 97.1%, respectively). Conclusion. Automatic quantitative measurements of gated and ungated volumes with our algorithm are repeatable, correlate well with other g lobal myocardial parameters, and may contribute important additional i nformation to that conventionally provided by myocardial perfusion SPE CT studies.