Human umbilical cord blood relaxation times and susceptibility at 3 <scp>T</scp>
Bibliographic record
Abstract
Purpose To characterize the magnetic susceptibility and relaxation times (T1 and T2) of fetal blood at 3 T as a function of the hematocrit (Hct) and oxygen saturation (sO2). Methods Susceptibility and relaxometry measurements were performed on cord blood specimens (N = 90, derived from six caesarean deliveries) with a range of hematocrits and oxygen saturations (0.09 < Hct < 0.82, 7 < sO2 < 100%). To obtain simple, analytic relationships between MRI properties and blood properties, data were fit to established two‐compartment (plasma and erythrocytes) models. Results Two‐compartment models effectively described the cord blood data. The root‐mean‐squared deviation between the model and the data was 6.3, 10.3, and 1.3% for fits to T1, T2, and susceptibility measurements. Relaxometry data and estimated T1 and T2 model parameters were generally consistent with those reported in cord blood at 1.5 T and comparable to published values for adult blood. Notably, the measured value of Δχdeo, the susceptibility difference between fully oxygenated (sO2 = 100%) and deoxygenated (sO2 = 0) cord blood was approximately 20% lower than the established adult blood value (Δχdeo,cord = 2.64 ppm, Δχdeo,adult = 3.4 ppm). Conclusions The described models and associated parameter values can be used to inform acquisition parameters, and interpret fetal/neonatal blood susceptibility measurements and relaxometry data acquired at 3 T with respect to hematocrit and sO2. Magn Reson Med 79:3194–3206, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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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 | 0.000 | 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".