Prospective Study of Intracranial Translucency and the Posterior Brain in Normal Fetuses at the 11‐ to 13‐Week Scan
Bibliographic record
Abstract
OBJECTIVES: To evaluate the ability of sonographers to prospectively identify intracranial translucency and posterior brain structures at 11 to 13 weeks and to evaluate measurement reproducibility of brain stem and brain stem-occipital bone diameters on stored images. METHODS: After specific training for intracranial translucency visualization, 10 nonphysician sonographers prospectively identified intracranial translucency at the 11- to 13-week scan, noting whether intracranial translucency was present, absent, or uncertain. If absent/uncertain, they documented the reason as spina bifida or an inadequate image (with reasons for the inadequate image). Measurements of brain stem and brain stem-occipital bone diameters were performed on stored images. Fifty randomly selected cases were reviewed for intraobserver and interobserver variability. RESULTS: In 313 singleton pregnancies, the posterior brain including intracranial translucency was evaluated; 293 (93.6%) had known pregnancy outcomes. None had open spina bifida, but 7 had chromosomal or congenital abnormalities. In the remaining 286 normal fetuses, intracranial translucency was seen in 275 (96%) and uncertain in 11 (4%), due to inadequate images (top 3 reasons were fetal position [n = 8], obesity [n = 5], and retroverted uterus [n = 4]). Fetal position and gestational age were significantly associated with intracranial translucency visualization (P < .05). Intraobserver and interobserver agreement rates were moderate for measurements of brain stem diameter (intraclass correlation coefficients, 0.59 and 0.57) and substantial for brain stem-occipital bone diameter (intraclass correlation coefficients, 0.76 and 0.61). Bland-Altman analysis revealed negligible intraobserver and interobserver differences in brain stem and brain stem-occipital bone diameter measurements. CONCLUSIONS: Intracranial translucency can be prospectively identified by trained sonographers in 96% of normal fetuses at 11 to 13 weeks. Measurements of brain stem and brain stem-occipital bone diameters are reproducible.
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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 | 0.003 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".