Abstract: Iterative reconstruction, such as ordered subsets expectation maximization (OSEM), incorporated with resolution recovery has been routinely used to improve image resolution in myocardial perfusion single photon emission computed tomography (SPECT). Compared with traditional filtered back-projection (FBP), this type of reconstruction may also adversely enhance image artifacts from soft-tissue attenuation or by scatter of extracardial activities. We demonstrate these findings from 2 patients who underwent Tc-99m sestamibi (MIBI) SPECT. In one patient, subdiaphragmatic attenuation artifact in FBP images was worsened with OSEM. In the other patient, a hot spot presented in FBP images was enhanced to decrease the image intensity in other myocardial segments due to adjacent hot bowel.