Respiratory gating and phase-matched attenuation correction improves uniformity of regional myocardial blood flow estimates during hypercapnea-induced stress imaging with dynamic rubidium-82 PET
Bibliographic record
Abstract
1960 Objectives The use of exogenous CO2 inhalation (hypercapnea) has been proposed as an alternative method to induce hyperemia for stress myocardial perfusion imaging (MPI). Breathing rate and tidal volume are increased dramatically in response to CO2, inducing a mismatch between PET and CT attenuation correction scans. Our objective is to determine the effect of respiratory gating and phase-matched attenuation correction on the uniformity of regional myocardial blood flow quantification during hypercapnia-induced stress imaging with dynamic rubidium-82 PET. Methods List-mode data from rest/ hypercapnea-stress scans in healthy normal subjects (N=7) were gated into four phases. Dynamic images from each phase, as well as the full ungated series, were reconstructed and analyzed for blood flow quantification using FlowQuant. Polar-map uniformity was measured as SD/mean of the 460 sectors, and differences between the four phases were evaluated using one-way ANOVA and post-hoc t-testing. Two-factor ANOVA was used to evaluate the regional variation in blood flow values using a 5-segment model. Results No significant differences in blood flow uniformity were found between respiratory phases at rest (p=0.75). For stress scans, significant differences in uniformity were found between the phases (p = 0.017). Post-hoc testing revealed no difference between the two inspiration phases, nor between the two expiration phases, but there were differences between the inspiration and expiration phases (46% vs 21%; p=0.002). Segmental ANOVA showed no effect due to inspiration vs expiration (p=0.49), but highly significant effects between segments (p Conclusions Respiratory gating and phase-matched attenuation correction decreases the variability of regional blood flow estimates, improving uniformity in healthy normals during hypercapnea -induced stress imaging with dynamic rubidium-82 PET.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| 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".