Sci—Thur PM: YIS — 05: Hyperpolarized Noble Gas Magnetic Resonance Imaging and Dynamic Spectroscopy of Rat Lungs
Bibliographic record
Abstract
Magnetic Resonance (MR) imaging using hyperpolarized noble gases (HNG's), 3He and 129Xe, provide non‐invasive approaches for probing lung function and structure. In particular, measurement of HNG ventilated lung volumes (e.g., ventilation defects) and apparent diffusion coefficients (ADC) are useful for characterizing chronic obstructive pulmonary disease (COPD) and emphysema. Of particular interest, hyperpolarized 129Xe also dissolves in the lung parenchyma and blood compartments, offering an interesting palette of potential biomarkers of pulmonary disease, including quantifying xenon diffusing capacity in inflammatory disease and may be useful for assessing pulmonary perfusion. 129Xe dissolved in tissue and blood experience large chemical shifts and can be selectively saturated and allowed to recover as a function of delay time as in the chemically selective saturation recovery (CSSR) technique. CSSR has previously been used to study surface‐to‐volume ratio (S/V) and diffusing capacity of xenon (DXe) in the lung which is analogous to diffusing capacity of carbon monoxide. In this work, the 129Xe CSSR technique is used to measure S/V ratios and Dxelp in whole healthy rat lungs as a function of ventilated lung volume assessed with 3He MR imaging. The data follow theoretically predicted trends for Ttr, S/V and DXeLP. In parallel to this study, 3D 129Xe imaging was also investigated and compared to 3He for lung volume assessment in an effort to remove the reliance on 3He which is costly and scarce. Absolute ventilated volumes (|VLV|) derived from preliminary results for 3He and 129Xe were 9.74 mL and 9.14 mL respectively for a pressure of 9.1cmH2O.
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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 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.027 | 0.007 |
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".