Intra<scp>‐</scp> and <scp>Inter‐visit</scp> Repeatability of <scp><sup>129</sup>Xenon Multiple‐Breath</scp> Washout <scp>MRI</scp> in Children With Stable Cystic Fibrosis Lung Disease
Bibliographic record
Abstract
Background Multiple‐breath washout (MBW) 129Xe MRI (MBW Xe‐MRI) is a promising technique for following pediatric cystic fibrosis (CF) lung disease progression. However, its repeatability in stable CF needs to be established to use it as an outcome measure for novel therapies. Purpose To assess intravisit and intervisit repeatability of MBW Xe‐MRI in healthy and CF children. Study Type Prospective, longitudinal cohort study. Subjects A total of 18 pediatric subjects (7 healthy, 11 CF). Field Strength/Sequence A 3 T/2D coronal hyperpolarized (HP) 129Xe images using GRE sequence. Assessment All subjects completed MBW Xe‐MRI, pulmonary function tests (PFTs) (spirometry, nitrogen [N2] MBW for lung clearance index [LCI]) and ventilation defect percent (VDP) at baseline (visit 1) and 1‐month after. Fractional ventilation (FV), coefficient of variation (CoVFV) maps were calculated from MBW Xe‐MRI data acquired between intervening air washout breaths performed after an initial xenon breath‐hold. Skewness of FV and CoVFV map distributions was also assessed. Statistical Tests Repeatability: intraclass correlation coefficients (ICC), within‐subject coefficient of variation (CV%), repeatability coefficient (CR). Agreement: Bland–Altman. For correlations between MBW Xe‐MRI, VDP and PFTs: Spearman's correlation. Significance threshold: P < 0.05. Results For FV, intravisit median [IQR] ICC was high in both healthy (0.94 [0.48, 0.99]) and CF (0.83 [0.04, 0.97]) subjects. CoVFV also had good intravisit ICC in healthy (0.92 [0.42, 0.99]) and CF (0.79 [0.02, 0.96]) subjects. Similarly, for FV, intervisit ICC was high in health (0.94 [0.68, 0.99]) and CF (0.89 [0.61, 0.97]). CoVFV also had good intervisit ICC in health (0.92 [0.42, 0.99]) and CF (0.78 [0.26, 0.94]). FV had better intervisit repeatability than VDP. CoVFV correlated significantly with LCI (R = 0.56). Skewness of FV distributions significantly distinguished between cohorts at baseline. Data Conclusion MBW Xe‐MRI had high intravisit and intervisit repeatability in healthy and stable CF subjects. CoVFV correlated with LCI, suggesting the importance of ventilation heterogeneity to early CF. Evidence Level 1. Technical Efficacy Stage 2.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".