2020 Volume 6 Issue 1 Pages 39-45
Background: Myocardial 18F-fluorodeoxyglucose (18F-FDG) uptake is a sign of active inflammation in patients with cardiac sarcoidosis (CS) under the correct circumstance. However, even under the proper preparation, diffuse myocardial 18F-FDG uptake is frequently observed in the failing heart and misleads the CS disease activity. The aim of this study was to establish the diagnostic value of resting myocardial perfusion single photon emission computed tomography (SPECT) for assessing CS disease activity in patients with diffuse myocardial 18F-FDG uptake.
Methods: We examined 39 patients with either histologically or clinically proven CS. All patients underwent 18F-FDG positron emission tomography (PET) and resting 99mTc-SPECT. The presence of perfusion–metabolic mismatch was evaluated with generating polar maps of 18F-FDG PET and 99mTc-SPECT images.
Results: Increased myocardial 18F-FDG uptake was observed in 33 (85%) of 39 patients. Focal 18F-FDG uptake was detected in 16 patients and diffuse 18F-FDG uptake was seen in 17 patients. Brain natriuretic peptide (BNP) levels were significantly higher in patients with diffuse 18F-FDG uptake than those with focal 18F-FDG uptake (p=0.002). With comparing polar maps of 18F-FDG PET and 99mTc-SPECT images, 8 of 16 patients with diffuse 18F-FDG uptake and myocardial perfusion defects demonstrated perfusion-metabolic mismatch which represented active inflammatory lesions in CS.
Conclusions: Simultaneous evaluation of myocardial 18F-FDG PET and 99mTc-SPECT by polar map analysis provides more relevant information for assessing disease activity in CS than 18F-FDG PET images alone. Perfusion–metabolic mismatch might indicate latent active inflammation in CS patients with diffuse myocardial 18F-FDG uptake, who had advanced heart failure.
