Relationship between myocardial flow reserve measured by a dynamic cadmium-zinc-telluride camera and increase rate in myocardial uptake of radionuclide during stress

Abstract

Abstract Objective A cadmium-zinc-telluride (CZT) camera can simultaneously evaluate the myocardial flow reserve (MFR) and perform myocardial perfusion imaging. Unlike conventional single-photon emission computed tomography (SPECT) cameras, it can detect multivessel coronary artery disease (CAD) without underestimation. However, obtaining MFR measurements using routine SPECT is difficult. To determine whether the increase rate (IR) could be an alternative in the absence of MFR measurements, we examined the relationship between the MFR measured simultaneously with a dynamic CZT camera and IR in myocardial radionuclide uptake during stress. Methods We retrospectively analyzed the clinical images of 52 patients who underwent dynamic SPECT for evaluation of suspected CAD (34 men and 18 women; mean age:66.1 ± 10.4 years) after injection of 99mTc-sestamibi for rest and stress imaging, respectively. Radionuclide was injected at 1 ml/s using an automatic injector and flushed with 30 ml of saline. Dynamic CZT SPECT imaging data for calculating MFR were analyzed using commercially available software. An increase in radionuclide uptake in the myocardium during stress was defined as IR, and CAD was detected using myocardial perfusion imaging. The IR was calculated as the stress image/rest image normalized by the dose. Results Comparing the global CAD diagnostic performance of MFR and the IR, the area under the receiver operating characteristic curve was 0.78 for MFR and 0.57 for the IR (p = 0.024, cutoff value of MFR was 2.46, and IR was 1.01). However, in the case of 3-vessel disease, 67% of the participants were below the cutoff value, even for IR, and the contribution to CAD diagnosis was higher than that for one- and 2-vessel disease. Conclusions The IR of myocardial uptake of radionuclides during stress may provide additional information for myocardial perfusion imaging, such as diagnosing 3-vessel disease, even when MFR measurements are impossible.