Optimizing Acquisition Parameters and Interpretive Methods of FDG-PET/CT With Rb-82

In this this investigation, 15 subjects with a high probability of cardiac sarcoidosis based on clinical criteria and abnormal cardiac FDG uptake on initial, clinically indicted FDG PET study will be considered for this study. The study will test the following Aims: Aim 1. Effect of FDG incubation time on visual and quantitative interpretation of FDG uptake. Changes in incubation time can affect imaging target:background ratios and study sensitivity/specificity. For the study-directed exam, all patients will undergo sequential cardiacfocused FDG-PET imaging at 90 and 120 minutes after injection of FDG. Imaging variables will be evaluated as below. Aim 2. Reproducibility of FDG and Rb82 PET findings on sequential imaging. It is unknown whether FDG-positive imaging findings in cardiac sarcoidosis are reproducible. All patients will undergo study-directed FDG-PET/CT with MPI imaging within approximately 2 weeks from initial clinical scan.