Comparison of ventilation defects quantified by Technegas SPECT and hyperpolarized 129Xe MRI
Bibliographic record
Abstract
Introduction: The ideal contrast agents for ventilation SPECT and MRI are Technegas and 129 Xe gas, respectively. Despite increasing interest in the clinical utility of ventilation imaging, these modalities have not been directly compared. Therefore, our objective was to compare the ventilation defect percent (VDP) assessed by Technegas SPECT and hyperpolarized 129 Xe MRI in patients scheduled to undergo lung cancer resection with and without pre-existing obstructive lung disease. Methods: Forty-one adults scheduled to undergo lung cancer resection performed same-day Technegas SPECT, hyperpolarized 129 Xe MRI, spirometry, and diffusing capacity of the lung for carbon monoxide (DL CO ). Ventilation abnormalities were quantified as the VDP using two different methods: adaptive thresholding (VDP T ) and k-means clustering (VDP K ). Correlation and agreement between VDP quantified by Technegas SPECT and 129 Xe MRI were determined by Spearman correlation and Bland-Altman analysis, respectively. Results: VDP measured by Technegas SPECT and 129 Xe MRI were correlated (VDP T : r = 0.48, p = 0.001; VDP K : r = 0.63, p < 0.0001). A 2.0% and 1.6% bias towards higher Technegas SPECT VDP was measured using the adaptive threshold method (VDP T : 23.0% ± 14.0% vs. 21.0% ± 5.2%, p = 0.81) and k-means method (VDP K : 9.4% ± 9.4% vs. 7.8% ± 10.0%, p = 0.02), respectively. For both modalities, higher VDP was correlated with lower FEV 1 /FVC (SPECT VDP T : r = −0.38, p = 0.01; MRI VDP K : r = −0.46, p = 0.002) and DL CO (SPECT VDP T : r = −0.61, p < 0.0001; MRI VDP K : r = −0.68, p < 0.0001). Subgroup analysis revealed that VDP measured by both modalities was significantly higher for participants with COPD (n = 13) than those with asthma (n = 6; SPECT VDP T : p = 0.007, MRI VDP K : p = 0.006) and those with no history of obstructive lung disease (n = 21; SPECT VDP T : p = 0.0003, MRI VDP K : p = 0.0003). Discussion: The burden of ventilation defects quantified by Technegas SPECT and 129 Xe MRI VDP was correlated and greater in participants with COPD when compared to those without. Our observations indicate that, despite substantial differences between the imaging modalities, quantitative assessment of ventilation defects by Technegas SPECT and 129 Xe MRI is comparable.
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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 | 0.000 | 0.000 |
| 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) | 0.000 | 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".