DEW-SC on the CZT camera was feasible and produced images that are not significantly different from those acquired on the INF camera. Although use of SC on CZT images does increase noise, the resultant noise does not introduce bias relative to the INF camera.

There were no significant differences between using a high-speed CT and using a slow-rotation CT for attenuation correction of SPECT myocardial perfusion images.

Common practice is to use separate CT scans acquired during rest and stress for attenuation correction of SPECT myocardial perfusion imaging (MPI). We evaluated using a single CT scan to correct both rest and stress SPECT scans. Studies from 154 patients were reprocessed using one CT acquired at stress to correct both rest and stress scans (1CT) and compared to correction of each scan with its own CT (2CT). Two expert readers independently read the images and determined summed stress (SSS), rest (SRS), and difference (SDS) scores. The correlation in SRS between 2CT and 1CT was r ≥ 0.88. The concordance in SDS was ≥0.84 (kappa ≥ 0.62). The mean SDS difference between 2CT and 1CT for the averaged observer was not significantly different from zero (p > 0.31). 1CT images had a small but significant increase in SRS and an increase in SDS variability. However, the mean SDS difference was similar to the mean inter-observer SDS difference for the 2CT approach (-0.08 vs -0.23, p = 0.46) and had less uncertainty (1.02 vs 2.05, p < 0.001). Thus, the differences between 1CT and 2CT are unlikely to be clinically significant, and the 1CT approach is feasible for SPECT MPI.

No abstract

Myocardial perfusion imaging (MPI) with single‐photon emission computed tomography (SPECT) is an important tool in the clinical management of heart disease. Simultaneous dual‐istope imaging offers a means to greatly reduce the time required for this test, but is limited by interference between the signals of the two isotopes. Newly developed dedicated cardiac SPECT cameras based on CZT detectors may reduce the interference between isotopes due to improved energy resolution. Our objective is to measure in clinical patients the magnitude of cross‐talk expected for simultaneous perfusion imaging with Tl‐201 and Tc‐99m‐tetrofosmin on a new CZT‐based multi‐pinhole dedicated cardiac SPECT camera. We retrospectively examined 25 matched pairs of Tl‐201 and Tc‐99m‐tetrofosmin patients. Reprocessing the listmode data, we determined the cross‐talk fraction for typical energy windows as well as for a Tc‐99m energy window that was reduced from 20% to 12%. Two protocols were considered: Tl‐rest/Tc‐stress and Tc‐rest / Tl‐stress. Cross‐talk into the Tl window was 74% and 36% respectively for the two protocols. Cross‐talk into the 10% Tc‐99m window was 2.4% and 11% respectively. The cross‐talk into the Tc‐99m window was reduced by 25% using a +/−6% window. Cross‐talk between Tc‐99m‐tetrofosmin and Tl‐201 has been assessed for the new dedicated CZT‐based cardiac SPECT cameras and the improved energy resolution of the CZT detectors decreases cross‐talk interference.