Gated Tomographic Radionuclide Angiography using 3D-ring CZT StarGuide SPECT/CT: head-to-head comparison with a cardiac-dedicated CZT camera.

Introduction: The StarGuide 3D-ring CZT-camera (GE Healthcare, Haifa, Israel) is equipped with 12 swiveling high-resolution CZT detectors and a CT in a hybrid system. Gated tomographic radionuclide angiography is a gold standard for the assessment and monitoring left cardiac function of patients under treatment at risk of cardiotoxicity (oncology). In this preliminary work, we compared the evaluation of left ventricle ejection fraction (LVEF) between the new CZT SPECT / CT Starguide system and a cardiac-dedicated CZT camera.

Methods: We conducted a prospective single-center, comparative (with intra-patient comparisons) study. Patients underwent a 7-minutes acquisition on a cardiac-dedicated CZT camera (Discovery NM 530c, GE Healthcare, Haifa, Israel) and 9-minutes on the new StarGuide CZT system, after mean injection of 321.4MBq 55.9 ^99mTc-labeled human serum albumin. The primary outcome was the comparison of LVEF between both cameras. Secondary outcomes included the measurements of right ventricle ejection fraction (RVEF) and left ventricular volumes. All Data were analyzed by BPGs software.

Results: Between December 2020 and April 2021, 26 patients were included (22 women; 4 men; mean age 56.9 Y; mean BMI 29.5 kg/m² (17-42)). Mean LVEF was 69.7% 11.6 (46% - 94%). There was no-significant difference between the two acquisition methods (p<0.0001) with a correlation coefficient of 0.75 (Pearson). The only abnormal patient (LEVF < 50%) was correctly classified on both systems (LVEF = 46% and 48% respectively for cardiac dedicated and 3D-ring CZT systems). Left ventricular volumes were also significant between the two systems (p<0.0001). Overall image quality seemed visually similar. RVEF seemed lower using StarGuide (mean RVEF 47.4 % 9.4 and 46.2% 10.4 respectively for cardiac-dedicated and 3D-ring CZT systems; p=0.08), mostly explained by contouring methods.

Conclusions: Our preliminary results seem to indicate that the use of StarGuide system for the LEVF and ventricular volumes measurement gives similar results to the use of a cardiac-dedicated CZT camera. RVEF seemed lower using this new system, but this might be explained because of greater variability in RV contouring. These results should be confirmed on a larger scale.