Left ventricular ejection fraction determined with the simulation of a very low-dose CZT-PECT protocol and an additional count-calibration on planar radionuclide angiographic data

Purpose. To determine whether the left ventricular ejection fractions (EFs), measured on a high-sensitivity CZT single photon emission computed tomography (SPECT)-camera with a 70% reduction in recording times and a prevention of EF overestimation through an additional count-calibration, are concordant with reference EF from planar radionuclide angiography (2DRNA). Methods. An additional 10-minute CZT-SPECT recording was performed in patients referred to 2D-RNA for cardiomyopathy (n=23) or chemotherapy monitoring (n=50) with an in vivo red blood cell labeling with 850 MBq (TcO4-)-Tc-99m. The EF, obtained from CZT-SPECT with 100% (SPECT100) or 30% (SPECT30) projection times and with a SPECT-count calibration on the 2D-RNA counts of corresponding cavity volumes, were compared to EF from 2D-RNA. Results. Strong and equivalent relationships were documented between the EF from 2DRNA and the calibrated EF from SPECT100 (y=0.89x+ 6.62; R-2=0.87) and SPECT30 (y=0.87x +8.40; R-2=0.85), and the mean EF from SPECT100 (54%+/- 15%) and SPECT30 (53%+/- 16%) were close to that from 2D-RNA (55%+/- 15%). However, upward shifts in these mean values were documented in the absence of count calibration for both SPECT100 (60%+/- 18%) and SPECT30 (60%+/- 18%). Conclusion. Left ventricular EF may be determined on a high-sensitivity CZT-camera, a 70% reduction in injected activities, and an additional count-calibration for further enhancing the concordance with 2D-RNA values.