Comparison of hyperpolarized <sup>3</sup>He and <sup>129</sup>Xe MRI for the measurement of absolute ventilated lung volume in rats
Bibliographic record
Abstract
PURPOSE: MRI using hyperpolarized noble gases, (3)He and (129)Xe, provides noninvasive assessments of lung structure and function. Previous work demonstrated that absolute ventilated lung volumes (aVLV) measured in rats using hyperpolarized (3)He agree well with micro-CT. METHODS: In this work, aVLV measurements were performed in rats using hyperpolarized (129)Xe MRI and compared with hyperpolarized (3)He measurements of aVLV under matched ventilation conditions. Whole-lung compliance was also determined. Partial volume, apparent diffusion coefficient, and effective transverse relaxation time corrections were applied during postprocessing to reduce bias between methods. RESULTS: Mean apparent diffusion coefficient of the trachea was 0.83 ± 0.09 cm(2)/s and 0.067 ± 0.011 cm(2)/s for (3)He and (129)Xe, respectively. Mean apparent diffusion coefficient of parenchyma was 0.21 ± 0.07 cm(2)/s and 0.027 ± 0.008 cm(2)/s for (3)He and (129)Xe, respectively. Mean transverse relaxation time values were 1.57 ± 0.25 ms and 2.80 ± 0.25 ms for (3)He and (129)Xe, respectively, in a model trachea and 3.18 ± 1.00 ms and 4.88 ± 0.60 ms for (3)He and (129)Xe, respectively, for lung parenchyma. Mean aVLV values were 7.07 ± 0.67 mL and 6.99 ± 1.00 mL at 14 cmH2O and 4.88 ± 0.71 mL and 5.36 ± 0.76 mL at 10 cmH2O obtained with (3)He and (129)Xe, respectively, demonstrating good agreement between (129)Xe and (3)He. CONCLUSIONS: (129)Xe offers an important alternative to (3)He for hyperpolarized gas MRI of aVLV in rats.
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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) | 0.000 | 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 | 0.000 | 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".