volume-based glucose metabolic analysis of fdg pet/ct: the optimum threshold and conditions to suppress physiological myocardial uptake

Fdg pet/ct plays a significant role in the diagnosis of inflammatory heart diseases and cardiac tumors. we attempted to determine the optimal fdg uptake threshold for volume-based analyses and to evaluate the relationship between the myocardial physiological uptake volume in fdg pet and several clinical factors. a total of 190 patients were retrospectively analyzed. the cardiac metabolic volume (cmv) was defined as a volume within the boundary determined by a threshold (suvmean of blood pool × 1.5). the suvmean of the blood pool measured in the descending aorta (da) (r = 0.86, intraclass correlation coefficient [icc] = 0.93, p < 0.0001) and that in the left ventricle (lv) cavity (r = 0.87, icc = 0.90, p < 0.0001) showed high inter-operator reproducibility. however, the suvmean in the lv cavity showed a significant correlation with the cmv (p = 0.0002, r = 0.26). the cmv in the patients who fasted < 18 hours were significantly higher (49.7  ±  73.2 vs. 18.0  ±  53.8 ml, p = 0.0013) compared to the patients with > 18-hour fasting. the multivariate analysis demonstrated that only the fasting period > 18 hours was independently associated with cmv = 0. our findings revealed that the da is suitable to decide the threshold for the volume-based analysis. the fasting time was significantly associated with the cardiac fdg uptake.