Feasibility of dynamic stress 201 Tl/rest 99m Tc-tetrofosmin single photon emission computed tomography for quantification of myocardial perfusion reserve in patients with stable coronary artery disease.

PURPOSE: We evaluated the feasibility of dynamic stress 201 Tl/rest 99m Tc-tetrofosmin SPECT imaging using a cardiac camera equipped with cadmium-zinc-telluride detectors for the quantification of myocardial perfusion reserve (MPR).

METHODS: Subjects with stable known or suspected coronary artery disease (CAD) who had undergone or were scheduled to undergo fractional flow reserve (FFR) measurement were prospectively enrolled. Dynamic stress 201 Tl/rest 99m Tc-tetrofosmin SPECT imaging was performed using a dedicated multiple pinhole SPECT camera with cadmium-zinc-telluride detectors. MPR was derived using Corridor4DM software.

RESULTS: A total of 34 subjects were enrolled (25 men and 9 women; mean age 60.4 years). FFR was measured in 65 coronary arteries with intermediate lesions. The average global MPR was 2.58 ± 1.03. Global MPR was associated with the extent of CAD (P = 0.028) and global summed stress score (r = -0.60, P < 0.001). Regional MPR showed a significant correlation with diameter stenosis (r = -0.57, P < 0.001), minimum lumen diameter (r = 0.50, P < 0.001), summed stress score (r = -0.52, P < 0.001) and FFR (r = 0.52, P < 0.001). The area under the receiver operating characteristic curve of MPR for the diagnosis of functionally significant stenosis (FFR ≤0.8) was 0.79 (P < 0.001). The sensitivity and specificity of regional MPR were 67% and 83%, respectively, using a cut-off value of 2.0.

CONCLUSION: Dynamic stress 201 Tl/rest 99m Tc-tetrofosmin SPECT imaging and quantification of MPR is feasible in patients with stable CAD. The preliminary results of this study in a small number of patients require confirmation in a larger cohort to determine their implications for bolstering the role of SPECT imaging in the diagnosis and risk prediction of CAD.