AIM AND METHODS: In order to estimate the effect of an epicardial or subcutan defibrillator patch electrode on the imaging of myocardium with SPET and PET we performed measurements with a body phantom and two different patch electrodes. RESULTS: We found that in 201TI-SPET with epicardial placing one electrode causes significant pseudodefects, which might lead to the impression of an infarction ("pseudoinfarction"), particularly in the case of reduced myocardial wall thickness. Measurements with 99nTc show the same pseudodefects. In case of subcutaneous placing the electrodes are much less likely to cause relevant absorption effects. With PET even epicardially placed both patch electrodes do not produce pseudodefects. Therefore the risk of false-positive findings is very small with PET. CONCLUSION: In order to avoid false positive findings in cardiovascular nuclear medicine caused by defibrillator patch electrodes, patients with patch electrodes should be referred to PET, if available.
