Lung volumes by computed tomography and plethysmography: are we measuring the same? CanCOLD study data
Bibliographic record
Abstract
Background: Measurement of lung volumes forms an integral part of pulmonary function testing. Lung volumes determined by computed tomography (CT) scans are well established, but the comparability to other methods like plethysmography in large cohorts remains in question. Methods: CanCOLD is a prospective longitudinal cohort study from Canada, including three matched groups of individuals with COPD I-II, smokers at risk and healthy controls. All participants underwent lung volume measurement by plethysmography and CT, using inspiratory and expiratory imaging. We compared total lung capacity (TLC) and residual volume (RV) in the different cohorts between plethysmography and CT. Results: Data from 1235 (518 females) individuals were analysed. Baseline characteristics were comparable in all three groups. Significant differences between CT and plethysmography could be observed in all groups, with consistently higher TLC and lower RV by plethysmography, respectively. Correlation was strong for TLC between the methods of measurement with a very stable bias of about 1.68 L for all groups, but the correlation was only low/moderate for RV. Variability of differences seemed to be higher for RV. No correction for supine position or dead airspace was used for CT-based measurements. Conclusion: Measurement of TLC and RV by plethysmography yields higher and lower values than by CT, respectively, so results of the different methods should not be used interchangeably.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.003 | 0.006 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".