Cardiac fluorine-18 fluorodeoxyglucose imaging using a dual-head gamma camera with coincidence detection: a clinical pilot study

Dual-headed gamma cameras with coincidence detection (MCD) are increasingly used for imaging of positron-emitting tracers, such as fluorine-18 fluorod eoxyglucose (FDG). In this study, we examined differences between FDG MCD a nd FDG positron emission tomography (PET) as the gold standard to determine whether FDG MCD could be used for assessment of myocardial viability in da ily practice. Nineteen patients with a previous myocardial infarction (17 m en: mean left ventricular ejection fraction 44%+/-13%) underwent FDG MCD, F DG PET, resting echocardiography and technetium-99m tetrofosmin gated singl e-photon emission tomography (SPET). At the 50% threshold value for FDG PET , the area under the receiver operating characteristic curve for FDG MCD wa s 0.77+/-0.03, In 107 dyssynergic segments on echocardiography and 151 segm ents with hypoperfusion on Tc-99m-tetrofosmin SPET. the specificity of FDG MCD for the detection of myocardial viability was 72% and 76% respectively, with a sensitivity of 69% and 72% respectively. Regional analysis showed a significantly lower agreement of FDG MCD and FDG PET in the inferior and s eptal regions (58% for dyssynergic segments and 65% for segments with hypop erfusion), as compared with the other regions (85% for dyssynergic regions, P<0.05, and 86% for segments with hypoperfusion, P<0.05). Five patients (2 6%). who all had a body mass index greater than or equal to 25% kg/m(2), sh owed more than 25% disagreement between FDG MCD and FDG PET. Because of the moderate overall agreement with FDG; PET, the low sensitivity in akinetic or dyskinetic regions and the low agreement in the inferior and septal regi ons, further studies and implementations of technical developments are need ed before FDG MCD can be introduced into clinical practice for the assessme nt of myocardial viability.