OC26.05: Amongst fetuses with conotruncal anomalies, how good is ultrasound measurement of the thymic‐thoracic ratio at identifying those with microdeletion 22q11?
Bibliographic record
Abstract
To determine if measurement of the thymic-thoracic ratio at midtrimester ultrasound in fetuses with conotruncal anomalies can discriminate between those with a normal karyotype and those with microdeletion 22q11. This was a historical case-control study. A regional, prenatal genetics clinical database was utilised to identify all fetuses diagnosed with conotruncal cardiac defects between January 2007 and December 2017. Amongst these fetuses, ‘cases’ were defined as those with microdeletion 22q11 and ‘controls’ were those with normal karyotypes. Post-processing measurements of the thymic-thoracic ratio from stored ultrasound images was performed by a blinded observer. Mean thymic-thoracic ratios and 95% confidence intervals were determined for each group. The student t-test was used to determine if any difference in thymic-thoracic ratios between groups was statistically significant, and sensitivities and specificities were calculated to determine the utility of this measurement as a diagnostic tool. In total, 81 fetuses with conotruncal anomalies were identified (26 cases with microdeletion 22q11 and 55 controls with normal karyotype). Amongst cases (conotruncal cardiac defect plus microdeletion 22q11), the mean thymic-thoracic ratio was 0.26 (95% CI 0.23 - 0.29). The mean thymic-thoracic ratio amongst controls (conotruncal defect and normal karyotype) was 0.37 (95% CI 0.35 - 0.39). This difference was statistically significant (P < 0.0001). When the 95 percentile is used as a cutoff, the thymic-thoracic ratio has 96% sensitivity and 96.4% specificity for detection of microdeletion 22q11. Measurement of the fetal thymic-thoracic ratio is a reliable marker of microdeletion 22q11 amongst fetuses with conotruncal defects. By using a cutoff of 0.29, the thymic-thoracic ratio is both sensitive and specific for the detection of microdeletion 22q11 and could easily be incorporated at the time of midtrimester scan.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.004 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".