Abstract 16689: Simultaneous Assessment of Cardiac Metabolism and Function Using PET/MR With Continuous FDG Infusion
Bibliographic record
Abstract
Background: We recently demonstrated the feasibility of simultaneous assessment of cardiac contractile function and metabolism in an animal model via positron emission tomography/magnetic resonance imaging (PET/MRI) with continuous 18 F-fluorodeoxyglucose ( 18 F-FDG) infusion. The aim of this study is to determine feasibility of utilizing continuous FDG infusion in human subjects to assess real-time response to cardiac stressors. Methods: Subjects underwent standard cardiac MRI while receiving continuous FDG infusion for 60 minutes, with the first 15 minutes in normoxia (FiO2 = 0.209) followed by 45 minutes in hypoxia (FiO2=0.12). Contractile response was measured via MRI analysis. For PET analysis, 3D regions of interest (ROIs) were drawn over the left ventricle, paraspinal muscles, right hepatic lobe, and blood pool. Average ROI values were extracted to develop time-activity curves, which were used to quantify the uptake (Ki) in each tissue of interest using Patlak Analysis (Figure 1). A paired t-test was used to compare changes from normoxia to hypoxia. Results: Hypoxia resulted in expected nonsignificant hemodynamic changes (Table 1). While skeletal muscle and liver showed significant decreases in glucose uptake during hypoxia, the myocardium did not demonstrate a significant shift in activity in this small sample size. Conclusion: Simultaneous PET/MR with continuous FDG infusion captures real time cardiac contractile activity and metabolism. Further investigation to refine this novel, noninvasive modality will be useful to study early shifts in cardiac metabolism and reserve, which may precede development of overt heart failure.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".