Comparison of interobserver variance between 99mTc-MIBI and 201Tl SPECT

Phase II and III clinical studies of Tc-99m hexakis 2-methyoxy-2-isobutyl isonitrile (Tc-99m MIBI) were performed in a total of 35 subjects, including 5 considered as normal, in myocardial perfusion SPECT imaging. The findings of Tc-99m MIBI SPECT were compared with those of convensional Tl-201 SPECT. According to the polar map display divided into 9 regions, normal distribution of Tc-99m MIBI was relatively homogeneous, although Tl-201 uptake was increased in the lateral segment and decreased in both the septal and inferior segments. Four nuclear medicine physicians visually reviewed both Tc-99m MIBI and Tl-201 SPECT images. In terms of complete and partial agreements, there was no significant interobserver variance between the two imaging agents. However, a significant interobserver discrepancy was observed for both the septal and inferior segments. (N.K.)