OP01.07: Subjective appraisal of fetal nasal bridge (Nbr) and/or bone (NB) for the risk of Down syndrome (DS) after 18 weeks' gestation
Bibliographic record
Abstract
To evaluate our impression that the Nbr is often thickened in fetuses with DS and that this potential marker as well as the NB can be subjectively evaluated in women who were referred with an increased risk for this aneuploidy after 18 weeks' gestation. Facial profile images of true DS cases were compared to those of controls without DS. All cases from Oct/03 with facial profile images were matched to randomly selected controls having a similar initial risk. Significant NB findings were if the NB was severely hypoplastic or absent. The Nbr was thickened if subjectively the entire NB was buried within the overriding Nbr tissue. Images were coded and then presented to three MFM specialists for a consensus evaluation. Each image was evaluated for adequacy of the profile and then the NB and Nbr were assessed as positive or negative. Statistical evaluation involved independent calculations for the NB and Nbr and then an evaluation of the combination of the two markers (either/or both). 118 cases (images) were evaluated of which 31 were discarded due to uninterruptible facial profile images. Among the 87 cases studied there were 22 with true DS based on chromosome analysis, while the 65 controls were normal based on either chromosomal analysis or normal neonatal exam. Subjective appraisal of both the fetal NB and Nbr after 18 weeks' gestation, in women at increased risk for DS, is valuable. These markers are likely not independent and carry significant and similar + ve likelihood rarios (LR). Nbr and NB combinations did not increase the + ve LR but did decrease the − ve LR. Given that both markers can easily be assessed on the same image we recommend that the Nbr also be evaluated whenever the NB is assessed. At least for women at increased risk, these markers should be included in the genetic sonogram.
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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 | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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".