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

We examined the relationship between myocardial flow reserve (MFR) measured simultaneously with a dynamic cadmium-zinc-telluride (CZT) camera and the increase rate (IR) in myocardial radionuclide uptake during stress to determine whether the IR could be a substitute in the absence of MFR measurements.

We analyzed the clinical images of 59 patients who underwent dynamic single-photon emission computed tomography (SPECT) to evaluate suspected coronary artery disease (CAD) after injection of ^99mTc-sestamibi for resting and stress imaging. MFR was calculated through the net retention method using a dynamic CZT-SPECT imaging data. Increased 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/resting image normalized to the dose.

Compared with the MFR, the IR tended to overlap more in the control and CAD groups, but there were also significant differences between the two groups for both the MFR and IR (MFR p < 0.0001, IR < 0.05). MFR and IR had sensitivities of 0.83 and 0.50 and specificity of 0.66 and 0.77, respectively. The area under the receiver operating characteristic curves were 0.80 for MFR and 0.62 for IR, with a confirmed significant difference (p < 0.05).

The global CAD diagnostic ability of the IR was lower than that of MFR. However, it was suggested that IR may provide additional information, such as the diagnosis of multivessel disease, as an adjunct to myocardial perfusion imaging because of its high specificity.