Evaluation of clinical variables affecting myocardial glucose uptake in cardiac FDG PET

Abstract Objective Cardiac 2-deoxy-2-F-18fluoro-D-glucose positron emission tomography (FDG PET) is widely used to assess myocardial viability in patients with ischemic heart disease. While sufficient glucose uptake is a prerequisite for accurate interpretation of cardiac viability, there is a lack of data on which clinical variables have the most significant impact on myocardial glucose metabolism. Therefore, this study was designed to evaluate several clinical variables that could affect myocardial glucose metabolism. Methods Between May 2018 and November 2022, a total of 214 consecutive cases were retrospectively enrolled in this study. All subjects were fasted for at least 8 hours. They received 250 mg of acipimox and underwent glucose loading as preparation for cardiac FDG PET/CT. Three-dimensional regions of interest (ROI) were drawn on PET/CT fusion images. SUV ratio (SUVmax of LV myocardium/SUVmean of liver) was then calculated. Clinical variables of age, sex, height, weight, body mass index (BMI), fasting blood glucose level, administered insulin dosage, blood glucose level at FDG injection, total cholesterol, high-density lipoprotein, low-density lipoprotein, cardiac markers, creatinine, hemoglobin A1c, and ejection fraction were measured and analyzed for correlation with myocardial glucose uptake. Participants were divided into an obese group and a non-obese group based on a BMI of 25. Whether there was a difference in myocardial glucose uptake between the two groups was then determined. Pearson correlation coefficient and Student’s t-test were used for statistical analysis. Results Myocardial uptake showed significant correlations with BMI (r = -0.162, p = 0.018), HbA1c (r = -0.150, p = 0.030), and triglyceride levels (r = -0.137, p = 0.046). No other clinical variables showed a significant correlation with myocardial glucose uptake. In group analysis, after dividing patients based on BMI, the obese group showed significantly lower myocardial uptake than the non-obese group (3.8 ± 1.9 vs. 4.4 ± 2.1, p = 0.031). Conclusions Among several clinical variables, BMI, HbA1c, and triglyceride levels exhibited negative correlations with myocardial glucose uptake. Patients with higher BMI, HbA1c, and triglyceride levels might require more thorough preparation or consideration during cardiac FDG PET exams to ensure optimal glucose uptake.