Cardiac studies in rats with /sup 11/C-acetate and PET: a comparison with /sup 13/N-ammonia
Bibliographic record
Abstract
Regional myocardial blood flow (MBF) can be assessed noninvasively with dynamic positron emission tomography (PET) and /sup 13/N-ammonia or /sup 11/C-acetate. The latter can also be used to estimate the myocardial oxygen consumption (MVO2) from the same time-activity curve. In this work, we explore the feasibility of such techniques for evaluating myocardial parameters in normal and ischemic rats (/spl sim/350 g) by dynamic imaging with the Sherbrooke small animal PET scanner. Scans were acquired in list mode for /sup 13/N-ammonia and /sup 11/C-acetate as two consecutive 15-min dynamic scans separated by a 5-min interval, without moving the rat from the scanner. Regions of interest (ROIs) were defined on four segments of the myocardium to extract the time-activity curves. Three-compartment models were applied to fit the /sup 13/N-ammonia and /sup 11/C-acetate data with three and four rate constants, respectively, plus blood volume. A reasonable agreement was observed between MBF estimates extracted from /sup 13/N-ammonia and /sup 11/C-acetate. MVO2 estimates, as given by the k/sub 2/ rate constant, were obtained with good reproducibility, indicating that myocardial metabolism can reliably be assessed concurrently with MBF using /sup 11/C-acetate. It is concluded that myocardial blood flow and oxygen consumption can be evaluated in rats with small animal PET scanners through high-rate, list-mode, dynamic imaging and kinetic modeling of /sup 13/N-ammonia and /sup 11/C-acetate.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".