To study the feasibility of cardiac ⁹⁹Tc^m-methoxyisobutylisonitrile (MIBI)/ ¹²³I-metaiodobenzylguanidine (MIBG) dual-isotope imaging with cadmium-zinc-telluride (CZT) SPECT.

Using a heart phantom, ⁹⁹Tc^m-MIBI single-isotope imaging and ⁹⁹Tc^m-MIBI/¹²³I-MIBG dual-isotope imaging were acquired separately. Model A, B, C represented normal heart, ⁹⁹Tc^m/¹²³I matched myocardium, ⁹⁹Tc^m/¹²³I mismatched myocardium, respectively. Nineteen patients (9 males, 10 females; age (56±16) years) from September 2018 to June 2020 at Fuwai Hospital were enrolled to participate ⁹⁹Tc^m-MIBI myocardial perfusion imaging and myocardial perfusion/cardiac sympathetic imaging with ⁹⁹Tc^m-MIBI/¹²³I-MIBG dual-isotope. Perfusion percent (PP%) and summed rest score (SRS) for all myocardial segments were obtained using quantitative perfusion SPECT (QPS) software by analyzing myocardial perfusion images. Difference and relationship between PP% and SRS were analyzed (Pearson and Spearman correlation analyses). No physical correction was applied for both acquisitions. Analysis of variance for repeated measurement data and Mann-Whitney U test were used.

There was no significant difference in myocardial perfusion images between ⁹⁹Tc^m single-isotope and ⁹⁹Tc^m/¹²³I dual-isotope imaging with the heart phantom. ¹²³I did not significantly impact on ⁹⁹Tc^m images. For patients, PP% did not differ between ⁹⁹Tc^m single-isotope ((69.2±14.5)%) and ⁹⁹Tc^m/¹²³I dual-isotope imaging ((69.5±16.2)%; F=0.005, P=0.946) and correlated well (r=0.845, P<0.01). SRS for⁹⁹Tc^m single-isotope was 2(1, 13) and 2(2, 12) for ⁹⁹Tc^m/¹²³I dual-isotope imaging (z=-0.774, P=0.439) and the correlation between the two acquisitions was excellent (r_s=0.975, P<0.01).

Even without physical correction, cardiac images interpretation won′t be significantly influenced by the interference of ¹²³I with relatively higher energy on ⁹⁹Tc^m images. Cardiac ⁹⁹Tc^m-MIBI/¹²³I-MIBG dual-isotope imaging is feasible.

Coronary artery disease; Myocardial perfusion imaging; Tomography, emission-computed, single-photon; Technetium Tc 99m sestamibi; 3-iodobenzylguanidine