Abstract WP50: Defining the Hyper-acute Infarct Core in Porcine Model of Cerebral Ischemia: A Multi-modality Imaging Study
Bibliographic record
Abstract
Background: Defining the hyper-acute infarct core can inform thrombolysis treatment. Clinical outcome and hemorrhagic transformation are correlated with infarct volume at admission. CT perfusion (CTP)-derived parameters and MR-diffusion weighted imaging (DWI) are currently used to delineate infarct volume; however, reversibility of such defects has been shown for both modalities. Methods: Six domestic pigs (mean weight 34.7kg) had a CTP scan prior to intracranial injection of endothelin-1 (ET-1; 0.01mL/kg) into the left striatum. Subsequent CTP scans at 30min, 1hr, 1.5hrs were done to monitor stroke progression. A second dose of ET-1 (0.01mL/kg) was injected at 2hrs from the first injection. Twenty minutes after the second ET-1 injection, 18F-FDG was injected. The animal was moved to a 3T MRI scanner where MR-DWI was performed. The animal was then moved back to the CT scanner for a final CTP/PET acquisition. The brain was quickly removed, cut into 10mm slices and stained with tetrazolium-chloride (TTC), the gold standard for defining final infarct volume. Using custom software, the infarct volume defined by low intensity TTC stain, low CBF (< 9.3ml•min-1•100g-1), low CBV (< 1.07ml•100g-1), DWI hyper-intensity and low F-18 FDG uptake were determined. A linear regression model was used to correlate the infarct volume measured by each imaging modality to that by the histological gold standard and the coefficients of correlation (R2) compared. Results: R2 values for CBF, CBV, DWI and FDG versus TTC-histology were 0.83, 0.69, 0.95 and 0.61, respectively. For the CBF and DWI parameters the slope of the fitted line was greater than 1, while the slope of the fitted line for the CBV and CBFxCBV parameters was less than 1. Mean normalized (relative to the histologically defined infarct) values were 1.38, 0.82, 0.99, and 0.67 for CBF, CBV, DWI and FDG, respectively. Conclusion: In this small sample study, the CTP-CBF and the imaging gold standard DWI both overestimated the TTC-infarct in 100% and 50% of cases, while CTP-CBV and FDG-PET both underestimated the final infarct volume in 100% of animals.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".