Structural and functional abnormalities in pulmonary gas exchange efficiency at rest and exercise in mild COPD: a Phase-Resolved Functional Lung (PREFUL)-MRI study
Bibliographic record
Abstract
Background: It remains unclear whether disturbances in lung ventilation (V)/perfusion (Q) distribution may occur in COPD patients showing only minor abnormalities in traditional pulmonary function tests (PFTs). Aim: To amalgamate advanced functional imaging (PREFUL-MRI) and respiratory physiology (breath-by-breath volumetric capnography) to uncover resting and exercise V/Q abnormalities in mild COPD. Methods: 16 patients (FEV1=88±13%pred, DLCO=79±17%) and 14 sex- and age-matched controls underwent PREFUL-MRI and volumetric capnography at rest and during two replicates of mild-moderate CPET in supine position. Results: Despite minimal emphysema on quantitative CT (<3%), patients showed larger areas of matched (low (⇓)V/⇓Q) and unmatched (⇓V/preserved (⇔)Q and, in particular, ⇔V/⇓Q) defects at rest and during exercise compared with controls (p<0.05; Fig 1A-C). These findings were associated with larger physiological and alveolar dead space (VDalv) and excess ventilation (Fig 1D-F). ⇔V/⇓Q, signalling wasted ventilation, correlated significantly with VDalv (r=0.51; p<0.05). erj;66/suppl_69/PA5180/F1 F1 F1 Conclusions: Substantial derangements in gas exchange efficiency coexist with absent/minor emphysema or functional deficits on PFTs in the earlier stages of COPD. Treating these abnormalities to improve breathlessness in carefully phenotyped patients remains an unmet clinical need.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".