Study on optimizing rapid acquisition time of CZT-SPECT myocardial perfusion imaging using different injection doses

Abstract

Objective To explore the optimal and rapid imaging acquisition time and clinical applicability when using high- and low-dose one day rest/stress myocardial perfusion imaging (MPI) with cadmium-zinc-telluride heart dedicated SPECT (CZT-SPECT). Methods The MPI data with high-dose rest/stress protocol in 51 patients (22 males, 29 females, age: (55.4±8.5) years) between November 2017 and December 2017 and those with low-dose protocol in 50 patients (27 males, 23 females, age: (59.1±12.8) years) between July 2018 and October 2018 were retrospectively analyzed. The MPI was performed with CZT-SPECT. Each patient received 296-370 MBq rest dose of 99Tcm-methoxyisobutylisonitrile (MIBI) for high-dose protocol, 111-222 MBq rest dose of 99Tcm-MIBI for low-dose protocol. Stress dose was 3 times of the corresponding rest dose. Rest and stress scans were acquired 6 min and 4 min for high-dose protocol, while 8 min and 6 min for low-dose protocol in total. All rest or stress imaging data were reconstructed from list-mode raw data to obtain scan durations of 1 min, 2 min, etc, up to the maximum of acquisition time. Image quality at different acquisition times were evaluated, and myocardial perfusion and function parameters were compared. Paired t test, Wilcoxon signed rank test, Pearson correlation and Bland-Altman analyses were used for data analysis. Results The image quality was rated as excellent/good in all patients (100%, 51/51) when acquisition time ≥3 min and ≥2 min respectively for rest and stress imaging with high-dose protocol, the similar results was obtained (100%, 50/50) when acquisition time ≥4 min and ≥3 min respectively for rest and stress imaging with low-dose protocol. The quantitative perfusion parameters(summed rest scores, summed stress scores, total perfusion deficit) and left ventricle ejection fraction (LVEF) at shorter acquisition times (3 min/2 min, 4 min/3 min) were not significantly different from the results at the longer acquisition times (6 min/4 min, 8 min/6 min; t values: from -1.196 to 1.597, z values: from -1.963 to 1.945, all P>0.05). Those parameters at shorter and longer acquisition times showed strong correlations (all r>0.700, all P<0.001), and Bland-Altman analysis revealed good agreement between them. Conclusion The optimal acquisition time is 3 min/2 min for high-dose one-day rest/stress CZT-SPECT MPI, and 4 min/3 min for low-dose protocol, which can significantly shorten the MPI acquisition time, then reliable perfusion parameters and LVEF can be obtained under the premise of ensuring image quality, making it the better clinical applicability. Key words: Coronary disease; Myocardial perfusion imaging; Cadmium; Zinc; Tellurium; Tomography, emission-computed, single-photon; Time management; Technetium Tc 99m sestamibi