Long fasting is effective and reproducible for inhibiting myocardial 18F-FDG physiological uptake in cardiac sarcoidosis.

1523 Objectives In order to detect cardiac sarcoidosis (CS), higher free fatty acids (FFA) levels and lower insulin levels are considered as the key factors for inhibiting myocardial 18F-FDG physiological uptake. Here, we assessed whether free fatty acids (FFA) level, insulin levels, triglyceride (TG) levels, and HOMA-R were important with long fasting (LF) method and whether LF was reproducible in the same patients. Methods From July 2012 to December 2014, 187 scans (115 patients with known or suspected CS) were performed with LF method. We divided them into two groups (group1, lower myocardial uptake than liver; group2, higher than liver) and compared the blood chemistry between them. We also evaluated 36 patients who had multiple PET scans (2 times, 19 patients; 3 times, 11 patients; 4 times, 5 patients; and 5 times, 1patient). Results 163 (87.2%) of 187 scans showed the lower myocardial uptake, and 19 higher. TG (p=0.009), FFA (p=0.005), and Long fasting hours (p=0.03) were significantly different between the two groups. Insulin and HOMA-R levels were not. Among the patients of multiple scans, 30 (85.7%) of the 35 patients showed only lower uptake in their multiple scans and 2 patients only higher uptake. Conclusions Long fasting is effective and reproducible. LF, FFA, and triglyceride levels are key factors for inhibiting the physiological myocardial uptake.