A 64-year-old male who received an implantable cardioverter defibrillator with epicardial patch electrodes in 1990 was admitted to the emergency room because of recurrent defibrillator shocks. During the following diagnostic work-up a remarkable discrepancy between coronary angiography (no significant stenosis), 201Thallium-SPECT imaging (antero-septal persistent defect) and PET imaging (no 18FDG defect) was noticed. In order to assess the impact of the epicardial defibrillator patch electrodes on the imaging, we performed SPECT and PET measurements using a thorax phantom. We found that in 201Tl-SPECT an epicardial patch caused a significant (up to 20%) photon attenuation, which may lead to the phenomenon of "pseudoinfarction". On PET images epicardial patch electrodes failed to produce any significant attenuation artifacts suggestive of infarction.
