Abstract 395: Myocardial Perfusion Imaging With a New Cadmium Zinc Telluride Based SPECT Camera
Background: A new solid-state SPECT camera (Discovery NM 530c, GE Healthcare) using cadmium zinc telluride (CZT) detectors and focused pinhole collimation has the potential for reducing image acquisition times.
Methods: 150 consecutive patients (95 men, mean age 62) underwent 1-day rest (296 MBq)/stress (888 MBq) Tc-99m-tetrofosmin gated SPECT imaging. Images were acquired with a standard dual-head gamma camera (Infinia Hawkeye 4, GE Healthcare) using a standard clinical protocol (rest 12.5 minutes, stress 12.5 minutes). Immediately following or preceding the standard acquisition, images were also acquired on the CZT camera (rest 5 minutes, stress 3 minutes) according to the vendor-recommended protocol. Two experienced physicians blindly performed clinical interpretation, assessed summed stress scores (SSS) using a 17 segment model, and determined left ventricular (LV) volumes and ejection fraction (EF).
Results: Clinical interpretation was identical in 145 studies (97% concordance, 0.93 kappa-coefficient). The SSS and LVEF correlated well (SSS: ICCr = 0.93, p <0.001; LVEF: ICCr = 0.85, p<0.001). Categorizing SSS as normal (0 –3), mild (4 – 8), moderate (9 –12) and severe (>12), McNemar’s test showed significant marginal inhomogeneities associated with larger SSS for CZT (p <0.01). Bland-Altman analysis showed an average increase in the CZT EDV and ESV of 11mL and 10mL respectively (p<0.001) and an average decrease of 5% for CZT LVEF (p<0.001).
Conclusion: Evaluation of perfusion using the new CZT camera using shorter imaging times versus standard SPECT imaging provides high concordance for clinical interpretation and very good correlation for SSS. The larger SSS and differences in LV volumes and EF are most likely due to the higher resolution of the CZT camera and will require further evaluation.