Cranial findings detected by second‐trimester ultrasound in fetuses with myelomeningocele: a systematic review
Bibliographic record
Abstract
BACKGROUND: Abnormal intracranial findings are often detected at mid-trimester ultrasound (US) in fetuses with myelomeningocele (MMC). It is unclear whether these findings constitute a spectrum of the disease or are an independent finding, which should contraindicate fetal surgery. OBJECTIVE: To ascertain the spectrum and frequency of US-detected cranial findings in fetuses with MMC. SEARCH STRATEGY: MEDLINE, Embase, Web of Science and CENTRAL were searched from January 2000 to June 2020. SELECTION CRITERIA: Study reporting incidence of cranial US findings in consecutive cases of second-trimester fetuses with MMC. DATA COLLECTION AND ANALYSIS: Publication quality was assessed by Newcastle-Ottawa Scale (NOS) and modified NOS. Meta-analysis could not be performed as a result of high clinical diversity and study heterogeneity. MAIN RESULTS: Fourteen cranial US findings were reported in 15 studies. Findings in classic Chiari II malformation (CIIM) spectrum included posterior fossa funnelling (96%), small transcerebellar diameter (82-96%), 'banana' sign (50-100%), beaked tectum (65%) and 'lemon' sign (53-100%). Additional cranial findings were small biparietal diameter (BPD) and head circumference (HC) (<5th centile; 53 and 71%, respectively), ventriculomegaly (45-89%), abnormal pointed shape of the occipital horn (77-78%), thinning of the posterior cerebrum, perinodular heterotopia (11%), abnormal gyration (3%), corpus callosum disorders (60%) and midline interhemispheric cyst (42%). CONCLUSIONS: We identified 14 cranial findings by second-trimester US in fetuses with MMC. The relatively high incidence of these findings and their unclear prognostic significance might not contraindicate fetal surgery in the case of normal fetal genetic testing. Some cranial findings may independently affect postnatal outcome, however. Long-term detailed follow-up is required to investigate this. TWEETABLE ABSTRACT: A high rate of cranial abnormalities found on second-trimester ultrasound in fetuses with myelomeningocele.
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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 | 0.017 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.005 |
| Bibliometrics | 0.011 | 0.012 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".