OC56: Developmental anatomy and morphology of the cerebellar vermis—essential knowledge for the imaging assessment of posterior fossa anomalies
Bibliographic record
Abstract
To define easily identifiable and reproducible measurements and markers of normal anatomical development of the cerebellar vermis in vivo. Analysis of the midline sagittal views of the cerebellar vermis was performed in over 200 consecutive fetal MR examinations performed for sonographically suspected CNS and non-CNS indications. Analysis included identification of the fastigial point, vermian lobules and fissures, tegmento-vermian angle, and associated abnormalities of the posterior fossa, brainstem, and CNS. Craniocaudal diameter of the cerebellar vermis follows growth approximately predicted by the linear equation: diameter (mm) = 0.74 × gestational age (weeks) − 6.11, with an R value of 0.89. Average height above and below the fastigial point also followed a linear progression, with average percentages above and below of 47.9% and 52.1% respectively, and no significant change of this ratio with gestational age. The tegmento-vermian angle was always < 2°in normal fetuses, but was often increased, and when significantly increased was always associated with vermian hypoplasia. The declive and primary fissure always were visible in normals from 17.5 weeks. The other cerebellar vermian fissures were seen at approximately the following gestational ages: secondary at 20 weeks, prepyramidal at 21 weeks, and preculmenate at 22 weeks. The other lobules became visible from 24 weeks and all were potentially visible by 27 weeks. Alterations of the landmarks were identified in cases of rhombencephalosynapsis, Joubert syndrome, Dandy-Walker continuum, congenital muscular dystrophy, vermian dysgenesis and vermian hypoplasias. Knowledge of normal vermian developmental morphology is essential when assessing for vermian hypoplasia. Specifically, the lobules are not all visible before approximately 27 weeks at the earliest and therefore other morphological features have to be used in addition to simply counting the lobules.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".