Utility of hyperpolarised xenon-129 magnetic resonance imaging in primary ciliary dyskinesia
Bibliographic record
Abstract
Background Managing patients with primary ciliary dyskinesia (PCD) is challenging due to limited therapeutic options and lack of sensitive, disease-specific outcome measures. Hyperpolarised 129-xenon magnetic resonance imaging (Xe MRI) is an emerging imaging modality that quantifies ventilation heterogeneity using the ventilation defect per cent (VDP). In other obstructive lung diseases, VDP has demonstrated increased sensitivity compared to conventional lung function measures; however, its utility in PCD has not been established. In PCD, we aimed to: 1) determine the feasibility of Xe MRI; 2) evaluate the same-day repeatability of VDP; and 3) explore the relationship between VDP with lung clearance index 2.5% (LCI 2.5 ) and forced expiratory volume in 1 s z-score (FEV 1 z). Methods In this cross-sectional observational study, participants >6 years old with confirmed PCD were recruited from two Canadian PCD centres. Participants underwent lung function testing to measure FEV 1 z and LCI 2.5 . Xe MRI was performed twice within 30–60 min to measure VDP. Intraclass correlation coefficient (ICC) and Bland–Altman plots (B&A) were used to assess same-day repeatability of VDP. Linear correlation between VDP with FEV 1 z and LCI 2.5 evaluated their relationships. Results 16 participants completed the study. In all participants, the VDP was elevated (VDP>2.3) with a median VDP of 11.05% (IQR: 4.83–13.67%). Same-day repeat Xe MRI VDP had an ICC>0.95 and B&A showed good agreement. VDP positively correlated with LCI 2.5 (r=0.89, p < 0.05) and negatively correlated with FEV 1 z (r=0.6, p < 0.05). Conclusions Xe MRI is a feasible imaging modality to capture lung disease in PCD. VDP has excellent same-day repeatability and correlated strongly with LCI 2.5 . Moreover, VDP was more sensitive at detecting lung function impairments than LCI 2.5 and FEV 1 z, demonstrating its potential as a sensitive outcome measure in PCD.
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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 | 0.002 | 0.004 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".